On 02/03/2022 12:06, Roland Perry wrote:
> Looking at FlightRadar24 just now there's an Osprey cruising across
> central Cambs at 3,700ft. Can't see any tankers; they'd be at whatever
> height that kind of aircraft is, 10 miles from landing.

I don't use FR24, I prefer ADS-B. Quite often see Osprey around that
general area, presume some based there.

On 2 Mar 2022 13:51:38 GMT, Marland <gemehabal@btinternet.co.uk> wrote:

>Recliner <recliner.usenet@gmail.com> wrote:
>>
>>
>> I don't think any floating wind farms are yet in operation, but they're
>> certainly on the way. Not only could they be moored in much deeper water,
>> but they may well be much further offshore, where the winds are stronger
>> and more reliable. So they'll be a greater hazard for shipping.
>>
>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>
>>
>>
>
> I suppose the hope of those on the green side trying to establish a new
>world order is that
>with electric generated by such turbines replacing oil for powering many
>things is that if their dream succeeds there will be far less tankers
>cruising the oceans anyway.

Yes, I'm sure that would be exactly what the Greens hope. And they're probably right to some extent.

On 02/03/2022 12:34, Recliner wrote:
> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>
>> On 01/03/2022 17:03, Graeme Wall wrote:
>>> On 01/03/2022 16:54, Recliner wrote:
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>> apart from being charted.
>>>>
>>>> I don't think any floating wind farms are yet in operation, but they're
>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>> but they may well be much further offshore, where the winds are stronger
>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>
>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>
>>> As that article points out, floating gas and oil platforms have been
>>> around a long time and are, by definition, going to be in seas traversed
>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>> the appropriate service tenders.
>>
>> How far can a floating generator wander? Obviously they'll be tethered,
>> rather than allowed to drift randomly off into the ocean, but there must
>> be some scope for moving around from their nominal location.
>
> Very little, I'd have thought. The tethers will partly have the role of keeping them upright in strong winds, so will
> have to be taut.

Just enough slack to allow the platform to ride the maximum sized waves
expected in the area.

--
Graeme Wall
This account not read.

Recliner <recliner.usenet@gmail.com> wrote:
> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>
>> On 01/03/2022 17:03, Graeme Wall wrote:
>>> On 01/03/2022 16:54, Recliner wrote:
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>> apart from being charted.
>>>>
>>>> I don't think any floating wind farms are yet in operation, but they're
>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>> but they may well be much further offshore, where the winds are stronger
>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>
>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>
>>>
>>> As that article points out, floating gas and oil platforms have been
>>> around a long time and are, by definition, going to be in seas traversed
>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>> the appropriate service tenders.
>>
>> How far can a floating generator wander? Obviously they'll be tethered,
>> rather than allowed to drift randomly off into the ocean, but there must
>> be some scope for moving around from their nominal location.
>
> Very little, I'd have thought. The tethers will partly have the role of
> keeping them upright in strong winds, so will
> have to be taut.

But also have to allow for rough seas, tidal changes and storm surges.
Presumably these are all solved problems for floating drilling rigs, but a
wind turbine will necessarily have different forces acting on it, and given
the number of them the solution may need to be cheaper.

Sam

--
The entity formerly known as Sam.Wilson@ed.ac.uk
Spit the dummy to reply

In message <svnt0h$f34$1@dont-email.me>, at 13:55:30 on Wed, 2 Mar 2022,
MB <MB@nospam.net> remarked:
>On 02/03/2022 12:06, Roland Perry wrote:

>> Looking at FlightRadar24 just now there's an Osprey cruising across
>> central Cambs at 3,700ft. Can't see any tankers; they'd be at whatever
>> height that kind of aircraft is, 10 miles from landing.
>
>I don't use FR24, I prefer ADS-B. Quite often see Osprey around that
>general area, presume some based there.

Mildenhall mainly, but the one I saw earlier had set off from nearby
Lakenheath.
--
Roland Perry

On 02/03/2022 14:15, Sam Wilson wrote:
> Recliner <recliner.usenet@gmail.com> wrote:
>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>
>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>> apart from being charted.
>>>>>
>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>> but they may well be much further offshore, where the winds are stronger
>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>
>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>
>>>>
>>>> As that article points out, floating gas and oil platforms have been
>>>> around a long time and are, by definition, going to be in seas traversed
>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>> the appropriate service tenders.
>>>
>>> How far can a floating generator wander? Obviously they'll be tethered,
>>> rather than allowed to drift randomly off into the ocean, but there must
>>> be some scope for moving around from their nominal location.
>>
>> Very little, I'd have thought. The tethers will partly have the role of
>> keeping them upright in strong winds, so will
>> have to be taut.
>
> But also have to allow for rough seas, tidal changes and storm surges.
> Presumably these are all solved problems for floating drilling rigs, but a
> wind turbine will necessarily have different forces acting on it, and given
> the number of them the solution may need to be cheaper.
>
> Sam
>

When a ship anchors, the anchor itself has little effect, the main
"anchoring" force is generated by the weight of the anchor chain. I
suspect this would be similar with floating platforms (oil or wind)
where the movement would be "controlled" by the chains. Inevitably this
will result in the anchored object being able to move in a limited area
(up and down and laterally).

--
Colin

ColinR <rail@greystane.shetland.co.uk> wrote:
> On 02/03/2022 14:15, Sam Wilson wrote:
>> Recliner <recliner.usenet@gmail.com> wrote:
>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>
>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>> apart from being charted.
>>>>>>
>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>
>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>
>>>>>
>>>>> As that article points out, floating gas and oil platforms have been
>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>> the appropriate service tenders.
>>>>
>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>> be some scope for moving around from their nominal location.
>>>
>>> Very little, I'd have thought. The tethers will partly have the role of
>>> keeping them upright in strong winds, so will
>>> have to be taut.
>>
>> But also have to allow for rough seas, tidal changes and storm surges.
>> Presumably these are all solved problems for floating drilling rigs, but a
>> wind turbine will necessarily have different forces acting on it, and given
>> the number of them the solution may need to be cheaper.
>>
>> Sam
>>
>
> When a ship anchors, the anchor itself has little effect, the main
> "anchoring" force is generated by the weight of the anchor chain. I
> suspect this would be similar with floating platforms (oil or wind)
> where the movement would be "controlled" by the chains. Inevitably this
> will result in the anchored object being able to move in a limited area
> (up and down and laterally).
>

I don't think that's how the turbines will be anchored. They'll have
multiple high tension cables to seabed anchors, so they'll have very little
horizontal, and no vertical movement. The cables have to be taut enough to
stop the turbine tipping over in gale force winds.

On 02/03/2022 16:11, Recliner wrote:
> ColinR <rail@greystane.shetland.co.uk> wrote:
>> On 02/03/2022 14:15, Sam Wilson wrote:
>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>
>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>> apart from being charted.
>>>>>>>
>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>
>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>
>>>>>>
>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>> the appropriate service tenders.
>>>>>
>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>> be some scope for moving around from their nominal location.
>>>>
>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>> keeping them upright in strong winds, so will
>>>> have to be taut.
>>>
>>> But also have to allow for rough seas, tidal changes and storm surges.
>>> Presumably these are all solved problems for floating drilling rigs, but a
>>> wind turbine will necessarily have different forces acting on it, and given
>>> the number of them the solution may need to be cheaper.
>>>
>>> Sam
>>>
>>
>> When a ship anchors, the anchor itself has little effect, the main
>> "anchoring" force is generated by the weight of the anchor chain. I
>> suspect this would be similar with floating platforms (oil or wind)
>> where the movement would be "controlled" by the chains. Inevitably this
>> will result in the anchored object being able to move in a limited area
>> (up and down and laterally).
>>
>
> I don't think that's how the turbines will be anchored. They'll have
> multiple high tension cables to seabed anchors, so they'll have very little
> horizontal, and no vertical movement. The cables have to be taut enough to
> stop the turbine tipping over in gale force winds.
>

And how would they cope with a 2-5 metre tidal rise and fall and up to
10m waves on top of that? There has to be some flexibility.

--
Colin

ColinR <rail@greystane.shetland.co.uk> wrote:
> On 02/03/2022 16:11, Recliner wrote:
>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>
>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>> apart from being charted.
>>>>>>>>
>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>
>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>
>>>>>>>
>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>> the appropriate service tenders.
>>>>>>
>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>> be some scope for moving around from their nominal location.
>>>>>
>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>> keeping them upright in strong winds, so will
>>>>> have to be taut.
>>>>
>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>> wind turbine will necessarily have different forces acting on it, and given
>>>> the number of them the solution may need to be cheaper.
>>>>
>>>> Sam
>>>>
>>>
>>> When a ship anchors, the anchor itself has little effect, the main
>>> "anchoring" force is generated by the weight of the anchor chain. I
>>> suspect this would be similar with floating platforms (oil or wind)
>>> where the movement would be "controlled" by the chains. Inevitably this
>>> will result in the anchored object being able to move in a limited area
>>> (up and down and laterally).
>>>
>>
>> I don't think that's how the turbines will be anchored. They'll have
>> multiple high tension cables to seabed anchors, so they'll have very little
>> horizontal, and no vertical movement. The cables have to be taut enough to
>> stop the turbine tipping over in gale force winds.
>>
>
> And how would they cope with a 2-5 metre tidal rise and fall and up to
> 10m waves on top of that? There has to be some flexibility.
>

Why? The sea would be penetrated by narrow cylindrical pillars, as with
semi-submersibles. The buoyancy tanks would be well underwater.

On 02/03/2022 14:42, Roland Perry wrote:
> Mildenhall mainly, but the one I saw earlier had set off from nearby
> Lakenheath.

There is a Osprey in the air around Mildenhall at the moment.

A BUFF went around the UK earlier, flew up the West coast then down the
East coast after spending a bit of time around the Moray Firth I think.

On 02/03/2022 16:27, Recliner wrote:
> ColinR <rail@greystane.shetland.co.uk> wrote:
>> On 02/03/2022 16:11, Recliner wrote:
>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>
>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>> apart from being charted.
>>>>>>>>>
>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>
>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>
>>>>>>>>
>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>> the appropriate service tenders.
>>>>>>>
>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>> be some scope for moving around from their nominal location.
>>>>>>
>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>> keeping them upright in strong winds, so will
>>>>>> have to be taut.
>>>>>
>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>> the number of them the solution may need to be cheaper.
>>>>>
>>>>> Sam
>>>>>
>>>>
>>>> When a ship anchors, the anchor itself has little effect, the main
>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>> suspect this would be similar with floating platforms (oil or wind)
>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>> will result in the anchored object being able to move in a limited area
>>>> (up and down and laterally).
>>>>
>>>
>>> I don't think that's how the turbines will be anchored. They'll have
>>> multiple high tension cables to seabed anchors, so they'll have very little
>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>> stop the turbine tipping over in gale force winds.
>>>
>>
>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>> 10m waves on top of that? There has to be some flexibility.
>>
>
> Why? The sea would be penetrated by narrow cylindrical pillars, as with
> semi-submersibles. The buoyancy tanks would be well underwater.
>

Ahh, you are not talking about floating platforms but effectively
tethered platforms. These are limited in water depths. Proper floating
platforms do not have pillars as you suggest. Have a look at the first
picture, two out of the three options are as I said, movable within a
limited area.
https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf

--
Colin

ColinR <rail@greystane.shetland.co.uk> wrote:
> On 02/03/2022 16:27, Recliner wrote:
>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>> On 02/03/2022 16:11, Recliner wrote:
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>>
>>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>>> apart from being charted.
>>>>>>>>>>
>>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>>
>>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>>> the appropriate service tenders.
>>>>>>>>
>>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>>> be some scope for moving around from their nominal location.
>>>>>>>
>>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>>> keeping them upright in strong winds, so will
>>>>>>> have to be taut.
>>>>>>
>>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>>> the number of them the solution may need to be cheaper.
>>>>>>
>>>>>> Sam
>>>>>>
>>>>>
>>>>> When a ship anchors, the anchor itself has little effect, the main
>>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>>> suspect this would be similar with floating platforms (oil or wind)
>>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>>> will result in the anchored object being able to move in a limited area
>>>>> (up and down and laterally).
>>>>>
>>>>
>>>> I don't think that's how the turbines will be anchored. They'll have
>>>> multiple high tension cables to seabed anchors, so they'll have very little
>>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>>> stop the turbine tipping over in gale force winds.
>>>>
>>>
>>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>>> 10m waves on top of that? There has to be some flexibility.
>>>
>>
>> Why? The sea would be penetrated by narrow cylindrical pillars, as with
>> semi-submersibles. The buoyancy tanks would be well underwater.
>>
>
> Ahh, you are not talking about floating platforms but effectively
> tethered platforms. These are limited in water depths. Proper floating
> platforms do not have pillars as you suggest. Have a look at the first
> picture, two out of the three options are as I said, movable within a
> limited area.
> https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf
>

Wouldn't my description apply to all three types? They all have multiple
taut anchoring cables.

On 02/03/2022 21:26, Recliner wrote:
> ColinR <rail@greystane.shetland.co.uk> wrote:
>> On 02/03/2022 16:27, Recliner wrote:
>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>> On 02/03/2022 16:11, Recliner wrote:
>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>>>
>>>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>>>> apart from being charted.
>>>>>>>>>>>
>>>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>>>
>>>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>>>> the appropriate service tenders.
>>>>>>>>>
>>>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>>>> be some scope for moving around from their nominal location.
>>>>>>>>
>>>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>>>> keeping them upright in strong winds, so will
>>>>>>>> have to be taut.
>>>>>>>
>>>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>>>> the number of them the solution may need to be cheaper.
>>>>>>>
>>>>>>> Sam
>>>>>>>
>>>>>>
>>>>>> When a ship anchors, the anchor itself has little effect, the main
>>>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>>>> suspect this would be similar with floating platforms (oil or wind)
>>>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>>>> will result in the anchored object being able to move in a limited area
>>>>>> (up and down and laterally).
>>>>>>
>>>>>
>>>>> I don't think that's how the turbines will be anchored. They'll have
>>>>> multiple high tension cables to seabed anchors, so they'll have very little
>>>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>>>> stop the turbine tipping over in gale force winds.
>>>>>
>>>>
>>>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>>>> 10m waves on top of that? There has to be some flexibility.
>>>>
>>>
>>> Why? The sea would be penetrated by narrow cylindrical pillars, as with
>>> semi-submersibles. The buoyancy tanks would be well underwater.
>>>
>>
>> Ahh, you are not talking about floating platforms but effectively
>> tethered platforms. These are limited in water depths. Proper floating
>> platforms do not have pillars as you suggest. Have a look at the first
>> picture, two out of the three options are as I said, movable within a
>> limited area.
>> https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf
>>
>
> Wouldn't my description apply to all three types? They all have multiple
> taut anchoring cables.
>

Nope, "taut" in the third option - the other two have distinctively
curved moorings meaning "not taut".

--
Colin

ColinR <rail@greystane.shetland.co.uk> wrote:
> On 02/03/2022 21:26, Recliner wrote:
>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>> On 02/03/2022 16:27, Recliner wrote:
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> On 02/03/2022 16:11, Recliner wrote:
>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>>>>
>>>>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>>>>> apart from being charted.
>>>>>>>>>>>>
>>>>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>>>>
>>>>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>>>>> the appropriate service tenders.
>>>>>>>>>>
>>>>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>>>>> be some scope for moving around from their nominal location.
>>>>>>>>>
>>>>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>>>>> keeping them upright in strong winds, so will
>>>>>>>>> have to be taut.
>>>>>>>>
>>>>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>>>>> the number of them the solution may need to be cheaper.
>>>>>>>>
>>>>>>>> Sam
>>>>>>>>
>>>>>>>
>>>>>>> When a ship anchors, the anchor itself has little effect, the main
>>>>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>>>>> suspect this would be similar with floating platforms (oil or wind)
>>>>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>>>>> will result in the anchored object being able to move in a limited area
>>>>>>> (up and down and laterally).
>>>>>>>
>>>>>>
>>>>>> I don't think that's how the turbines will be anchored. They'll have
>>>>>> multiple high tension cables to seabed anchors, so they'll have very little
>>>>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>>>>> stop the turbine tipping over in gale force winds.
>>>>>>
>>>>>
>>>>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>>>>> 10m waves on top of that? There has to be some flexibility.
>>>>>
>>>>
>>>> Why? The sea would be penetrated by narrow cylindrical pillars, as with
>>>> semi-submersibles. The buoyancy tanks would be well underwater.
>>>>
>>>
>>> Ahh, you are not talking about floating platforms but effectively
>>> tethered platforms. These are limited in water depths. Proper floating
>>> platforms do not have pillars as you suggest. Have a look at the first
>>> picture, two out of the three options are as I said, movable within a
>>> limited area.
>>> https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf
>>>
>>
>> Wouldn't my description apply to all three types? They all have multiple
>> taut anchoring cables.
>>
>
> Nope, "taut" in the third option - the other two have distinctively
> curved moorings meaning "not taut".
>

Spar Buoy: The foundation is kept in position by catenary or taut spread
mooring lines with drag or suction anchors.

Spar Submersible: The foundation is kept in position by catenary or taut
spread mooring lines and drag anchors.

In all three cases, the electric power connection will severely constrain
movement. Why would you want movement anyway?

On 02/03/2022 23:18, Recliner wrote:
> ColinR <rail@greystane.shetland.co.uk> wrote:
>> On 02/03/2022 21:26, Recliner wrote:
>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>> On 02/03/2022 16:27, Recliner wrote:
>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>> On 02/03/2022 16:11, Recliner wrote:
>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>>>>>
>>>>>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>>>>>> apart from being charted.
>>>>>>>>>>>>>
>>>>>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>>>>>
>>>>>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>>>>>> the appropriate service tenders.
>>>>>>>>>>>
>>>>>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>>>>>> be some scope for moving around from their nominal location.
>>>>>>>>>>
>>>>>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>>>>>> keeping them upright in strong winds, so will
>>>>>>>>>> have to be taut.
>>>>>>>>>
>>>>>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>>>>>> the number of them the solution may need to be cheaper.
>>>>>>>>>
>>>>>>>>> Sam
>>>>>>>>>
>>>>>>>>
>>>>>>>> When a ship anchors, the anchor itself has little effect, the main
>>>>>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>>>>>> suspect this would be similar with floating platforms (oil or wind)
>>>>>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>>>>>> will result in the anchored object being able to move in a limited area
>>>>>>>> (up and down and laterally).
>>>>>>>>
>>>>>>>
>>>>>>> I don't think that's how the turbines will be anchored. They'll have
>>>>>>> multiple high tension cables to seabed anchors, so they'll have very little
>>>>>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>>>>>> stop the turbine tipping over in gale force winds.
>>>>>>>
>>>>>>
>>>>>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>>>>>> 10m waves on top of that? There has to be some flexibility.
>>>>>>
>>>>>
>>>>> Why? The sea would be penetrated by narrow cylindrical pillars, as with
>>>>> semi-submersibles. The buoyancy tanks would be well underwater.
>>>>>
>>>>
>>>> Ahh, you are not talking about floating platforms but effectively
>>>> tethered platforms. These are limited in water depths. Proper floating
>>>> platforms do not have pillars as you suggest. Have a look at the first
>>>> picture, two out of the three options are as I said, movable within a
>>>> limited area.
>>>> https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf
>>>>
>>>
>>> Wouldn't my description apply to all three types? They all have multiple
>>> taut anchoring cables.
>>>
>>
>> Nope, "taut" in the third option - the other two have distinctively
>> curved moorings meaning "not taut".
>>
>
> Spar Buoy: The foundation is kept in position by catenary or taut spread
> mooring lines with drag or suction anchors.
>
> Spar Submersible: The foundation is kept in position by catenary or taut
> spread mooring lines and drag anchors.
>
> In all three cases, the electric power connection will severely constrain
> movement. Why would you want movement anyway?

To allow for waves.

--
Graeme Wall
This account not read.

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 02/03/2022 23:18, Recliner wrote:
>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>> On 02/03/2022 21:26, Recliner wrote:
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> On 02/03/2022 16:27, Recliner wrote:
>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>> On 02/03/2022 16:11, Recliner wrote:
>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>>>>>>> apart from being charted.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>>>>>>> the appropriate service tenders.
>>>>>>>>>>>>
>>>>>>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>>>>>>> be some scope for moving around from their nominal location.
>>>>>>>>>>>
>>>>>>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>>>>>>> keeping them upright in strong winds, so will
>>>>>>>>>>> have to be taut.
>>>>>>>>>>
>>>>>>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>>>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>>>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>>>>>>> the number of them the solution may need to be cheaper.
>>>>>>>>>>
>>>>>>>>>> Sam
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> When a ship anchors, the anchor itself has little effect, the main
>>>>>>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>>>>>>> suspect this would be similar with floating platforms (oil or wind)
>>>>>>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>>>>>>> will result in the anchored object being able to move in a limited area
>>>>>>>>> (up and down and laterally).
>>>>>>>>>
>>>>>>>>
>>>>>>>> I don't think that's how the turbines will be anchored. They'll have
>>>>>>>> multiple high tension cables to seabed anchors, so they'll have very little
>>>>>>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>>>>>>> stop the turbine tipping over in gale force winds.
>>>>>>>>
>>>>>>>
>>>>>>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>>>>>>> 10m waves on top of that? There has to be some flexibility.
>>>>>>>
>>>>>>
>>>>>> Why? The sea would be penetrated by narrow cylindrical pillars, as with
>>>>>> semi-submersibles. The buoyancy tanks would be well underwater.
>>>>>>
>>>>>
>>>>> Ahh, you are not talking about floating platforms but effectively
>>>>> tethered platforms. These are limited in water depths. Proper floating
>>>>> platforms do not have pillars as you suggest. Have a look at the first
>>>>> picture, two out of the three options are as I said, movable within a
>>>>> limited area.
>>>>> https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf
>>>>>
>>>>
>>>> Wouldn't my description apply to all three types? They all have multiple
>>>> taut anchoring cables.
>>>>
>>>
>>> Nope, "taut" in the third option - the other two have distinctively
>>> curved moorings meaning "not taut".
>>>
>>
>> Spar Buoy: The foundation is kept in position by catenary or taut spread
>> mooring lines with drag or suction anchors.
>>
>> Spar Submersible: The foundation is kept in position by catenary or taut
>> spread mooring lines and drag anchors.
>>
>> In all three cases, the electric power connection will severely constrain
>> movement. Why would you want movement anyway?
>
> To allow for waves.

But if the mooring is taut there wouldn’t be much movement anyway, and
you’d probably design it so that the floatation was below the surface so
that wave and tide height didn’t affect the buoyancy. There’s still the
question of windage but there’s another image on p6 of the document showing
turbines sharing a foundation, and rafting like that could be used to
reduce the tipping moment of the wind on the turbine mast(s).

Sam

--
The entity formerly known as Sam.Wilson@ed.ac.uk
Spit the dummy to reply

On 03/03/2022 08:22, Sam Wilson wrote:
> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>> On 02/03/2022 23:18, Recliner wrote:
>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>> On 02/03/2022 21:26, Recliner wrote:
>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>> On 02/03/2022 16:27, Recliner wrote:
>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>> On 02/03/2022 16:11, Recliner wrote:
>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>>>>>>>> apart from being charted.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>>>>>>>> the appropriate service tenders.
>>>>>>>>>>>>>
>>>>>>>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>>>>>>>> be some scope for moving around from their nominal location.
>>>>>>>>>>>>
>>>>>>>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>>>>>>>> keeping them upright in strong winds, so will
>>>>>>>>>>>> have to be taut.
>>>>>>>>>>>
>>>>>>>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>>>>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>>>>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>>>>>>>> the number of them the solution may need to be cheaper.
>>>>>>>>>>>
>>>>>>>>>>> Sam
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> When a ship anchors, the anchor itself has little effect, the main
>>>>>>>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>>>>>>>> suspect this would be similar with floating platforms (oil or wind)
>>>>>>>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>>>>>>>> will result in the anchored object being able to move in a limited area
>>>>>>>>>> (up and down and laterally).
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> I don't think that's how the turbines will be anchored. They'll have
>>>>>>>>> multiple high tension cables to seabed anchors, so they'll have very little
>>>>>>>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>>>>>>>> stop the turbine tipping over in gale force winds.
>>>>>>>>>
>>>>>>>>
>>>>>>>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>>>>>>>> 10m waves on top of that? There has to be some flexibility.
>>>>>>>>
>>>>>>>
>>>>>>> Why? The sea would be penetrated by narrow cylindrical pillars, as with
>>>>>>> semi-submersibles. The buoyancy tanks would be well underwater.
>>>>>>>
>>>>>>
>>>>>> Ahh, you are not talking about floating platforms but effectively
>>>>>> tethered platforms. These are limited in water depths. Proper floating
>>>>>> platforms do not have pillars as you suggest. Have a look at the first
>>>>>> picture, two out of the three options are as I said, movable within a
>>>>>> limited area.
>>>>>> https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf
>>>>>>
>>>>>
>>>>> Wouldn't my description apply to all three types? They all have multiple
>>>>> taut anchoring cables.
>>>>>
>>>>
>>>> Nope, "taut" in the third option - the other two have distinctively
>>>> curved moorings meaning "not taut".
>>>>
>>>
>>> Spar Buoy: The foundation is kept in position by catenary or taut spread
>>> mooring lines with drag or suction anchors.
>>>
>>> Spar Submersible: The foundation is kept in position by catenary or taut
>>> spread mooring lines and drag anchors.
>>>
>>> In all three cases, the electric power connection will severely constrain
>>> movement. Why would you want movement anyway?
>>
>> To allow for waves.
>
> But if the mooring is taut there wouldn’t be much movement anyway, and
> you’d probably design it so that the floatation was below the surface so
> that wave and tide height didn’t affect the buoyancy. There’s still the
> question of windage but there’s another image on p6 of the document showing
> turbines sharing a foundation, and rafting like that could be used to
> reduce the tipping moment of the wind on the turbine mast(s).
>

One diagram I saw a while ago[1] showed 4 turbines, one on each corner
of a square platform. I suspect that might be pushing things a bit.

[1] Son of an old friend works in the industry. He's mainly involved in
on-shore fields up till now.

--
Graeme Wall
This account not read.

Graeme Wall <rail@greywall.demon.co.uk> wrote:
> On 03/03/2022 08:22, Sam Wilson wrote:
>> Graeme Wall <rail@greywall.demon.co.uk> wrote:
>>> On 02/03/2022 23:18, Recliner wrote:
>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>> On 02/03/2022 21:26, Recliner wrote:
>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>> On 02/03/2022 16:27, Recliner wrote:
>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>> On 02/03/2022 16:11, Recliner wrote:
>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>> On 02/03/2022 14:15, Sam Wilson wrote:
>>>>>>>>>>>> Recliner <recliner.usenet@gmail.com> wrote:
>>>>>>>>>>>>> On Wed, 2 Mar 2022 11:17:39 +0000, Certes <none@nowhere.net> wrote:
>>>>>>>>>>>>>
>>>>>>>>>>>>>> On 01/03/2022 17:03, Graeme Wall wrote:
>>>>>>>>>>>>>>> On 01/03/2022 16:54, Recliner wrote:
>>>>>>>>>>>>>>>> ColinR <rail@greystane.shetland.co.uk> wrote:
>>>>>>>>>>>>>>>>> Whilst true, there are well advanced plans (maybe even actual) for
>>>>>>>>>>>>>>>>> floating wind turbines - these would, I assume, be able to be moored in
>>>>>>>>>>>>>>>>> deeper water. But they would present a fairly robust radar echo quite
>>>>>>>>>>>>>>>>> apart from being charted.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I don't think any floating wind farms are yet in operation, but they're
>>>>>>>>>>>>>>>> certainly on the way. Not only could they be moored in much deeper water,
>>>>>>>>>>>>>>>> but they may well be much further offshore, where the winds are stronger
>>>>>>>>>>>>>>>> and more reliable.  So they'll be a greater hazard for shipping.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> <https://www.ge.com/news/reports/deep-water-wind-these-huge-floating-wind-turbines-could-help-america-meet-its-renewable>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> As that article points out, floating gas and oil platforms have been
>>>>>>>>>>>>>>> around a long time and are, by definition, going to be in seas traversed
>>>>>>>>>>>>>>> by oil/gas tankers. The only vessels that need to go near wind farms are
>>>>>>>>>>>>>>> the appropriate service tenders.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> How far can a floating generator wander? Obviously they'll be tethered,
>>>>>>>>>>>>>> rather than allowed to drift randomly off into the ocean, but there must
>>>>>>>>>>>>>> be some scope for moving around from their nominal location.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Very little, I'd have thought. The tethers will partly have the role of
>>>>>>>>>>>>> keeping them upright in strong winds, so will
>>>>>>>>>>>>> have to be taut.
>>>>>>>>>>>>
>>>>>>>>>>>> But also have to allow for rough seas, tidal changes and storm surges.
>>>>>>>>>>>> Presumably these are all solved problems for floating drilling rigs, but a
>>>>>>>>>>>> wind turbine will necessarily have different forces acting on it, and given
>>>>>>>>>>>> the number of them the solution may need to be cheaper.
>>>>>>>>>>>>
>>>>>>>>>>>> Sam
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> When a ship anchors, the anchor itself has little effect, the main
>>>>>>>>>>> "anchoring" force is generated by the weight of the anchor chain. I
>>>>>>>>>>> suspect this would be similar with floating platforms (oil or wind)
>>>>>>>>>>> where the movement would be "controlled" by the chains. Inevitably this
>>>>>>>>>>> will result in the anchored object being able to move in a limited area
>>>>>>>>>>> (up and down and laterally).
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> I don't think that's how the turbines will be anchored. They'll have
>>>>>>>>>> multiple high tension cables to seabed anchors, so they'll have very little
>>>>>>>>>> horizontal, and no vertical movement. The cables have to be taut enough to
>>>>>>>>>> stop the turbine tipping over in gale force winds.
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>> And how would they cope with a 2-5 metre tidal rise and fall and up to
>>>>>>>>> 10m waves on top of that? There has to be some flexibility.
>>>>>>>>>
>>>>>>>>
>>>>>>>> Why? The sea would be penetrated by narrow cylindrical pillars, as with
>>>>>>>> semi-submersibles. The buoyancy tanks would be well underwater.
>>>>>>>>
>>>>>>>
>>>>>>> Ahh, you are not talking about floating platforms but effectively
>>>>>>> tethered platforms. These are limited in water depths. Proper floating
>>>>>>> platforms do not have pillars as you suggest. Have a look at the first
>>>>>>> picture, two out of the three options are as I said, movable within a
>>>>>>> limited area.
>>>>>>> https://www.irena.org/-/media/Files/IRENA/Agency/Publication/2016/IRENA_Offshore_Wind_Floating_Foundations_2016.pdf
>>>>>>>
>>>>>>
>>>>>> Wouldn't my description apply to all three types? They all have multiple
>>>>>> taut anchoring cables.
>>>>>>
>>>>>
>>>>> Nope, "taut" in the third option - the other two have distinctively
>>>>> curved moorings meaning "not taut".
>>>>>
>>>>
>>>> Spar Buoy: The foundation is kept in position by catenary or taut spread
>>>> mooring lines with drag or suction anchors.
>>>>
>>>> Spar Submersible: The foundation is kept in position by catenary or taut
>>>> spread mooring lines and drag anchors.
>>>>
>>>> In all three cases, the electric power connection will severely constrain
>>>> movement. Why would you want movement anyway?
>>>
>>> To allow for waves.
>>
>> But if the mooring is taut there wouldn’t be much movement anyway, and
>> you’d probably design it so that the floatation was below the surface so
>> that wave and tide height didn’t affect the buoyancy. There’s still the
>> question of windage but there’s another image on p6 of the document showing
>> turbines sharing a foundation, and rafting like that could be used to
>> reduce the tipping moment of the wind on the turbine mast(s).
>>
>
> One diagram I saw a while ago[1] showed 4 turbines, one on each corner
> of a square platform. I suspect that might be pushing things a bit.

Those sort of concepts would be based on using quite small turbines from
long ago that won't interfere with each other. But such turbines are much
less efficient than the huge turbines now being installed:

… the dimensions of these turbines are big: the Vestas turbine will have a
blade length of 115.5 meters and a rotor diameter of 236 meters. SGRE’s
design incorporates 108 meter blades and a rotor diameter of 222 meters.

In message <Y7pTIcpq21HiFArM@perry.uk>, at 12:06:02 on Wed, 2 Mar 2022,
Roland Perry <roland@perry.co.uk> remarked:
>In message <svm669$naj$1@dont-email.me>, at 22:19:53 on Tue, 1 Mar
>2022, Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>Roland Perry <roland@perry.co.uk> wrote:
>>> In message <svl0ir$fl9$1@dont-email.me>, at 11:38:03 on Tue, 1 Mar 2022,
>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>>
>>>> When the Mildenhall KC-135s do racetracks over the North Sea there are
>>>> rarely any other aircraft visible in attendance.
>>>
>>> Do you mean "in attendance and being refuelled"?
>>
>>I mean visible on FlightRadar24. There are often F-15s, Typhoons and Hawks
>>shown on FR24 but miraculously they never seem to go near either the
>>KC-135s or the other tankers while they’re running the racetrack patterns.
>>
>>> FWIW those tankers frequently fly literally over my house (+/- 50m) and
>>> the base commander keeps his hand in flying one from time to time. Why
>>> do I know that - I had lunch with him a few years ago. Hopefully I won't
>>> now get a visit from any black helicopters (they prefer to use Ospreys)
>>>
>>> https://www.youtube.com/watch?v=F9snZJadgkQ
>>
>>The KC-135s fly over a family member’s house too, but at a considerably
>>higher altitude. I’ve not seen an Osprey yet.
>
>Looking at FlightRadar24 just now there's an Osprey cruising across
>central Cambs at 3,700ft. Can't see any tankers; they'd be at whatever
>height that kind of aircraft is, 10 miles from landing.

An RC135W 10 miles out at 2pm today, 2,100 ft.
--
Roland Perry

Roland Perry <roland@perry.co.uk> wrote:
> In message <Y7pTIcpq21HiFArM@perry.uk>, at 12:06:02 on Wed, 2 Mar 2022,
> Roland Perry <roland@perry.co.uk> remarked:
>> In message <svm669$naj$1@dont-email.me>, at 22:19:53 on Tue, 1 Mar
>> 2022, Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>> Roland Perry <roland@perry.co.uk> wrote:
>>>> In message <svl0ir$fl9$1@dont-email.me>, at 11:38:03 on Tue, 1 Mar 2022,
>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>>>
>>>>> When the Mildenhall KC-135s do racetracks over the North Sea there are
>>>>> rarely any other aircraft visible in attendance.
>>>>
>>>> Do you mean "in attendance and being refuelled"?
>>>
>>> I mean visible on FlightRadar24. There are often F-15s, Typhoons and Hawks
>>> shown on FR24 but miraculously they never seem to go near either the
>>> KC-135s or the other tankers while they’re running the racetrack patterns.
>>>
>>>> FWIW those tankers frequently fly literally over my house (+/- 50m) and
>>>> the base commander keeps his hand in flying one from time to time. Why
>>>> do I know that - I had lunch with him a few years ago. Hopefully I won't
>>>> now get a visit from any black helicopters (they prefer to use Ospreys)
>>>>
>>>> https://www.youtube.com/watch?v=F9snZJadgkQ
>>>
>>> The KC-135s fly over a family member’s house too, but at a considerably
>>> higher altitude. I’ve not seen an Osprey yet.
>>
>> Looking at FlightRadar24 just now there's an Osprey cruising across
>> central Cambs at 3,700ft. Can't see any tankers; they'd be at whatever
>> height that kind of aircraft is, 10 miles from landing.
>
> An RC135W 10 miles out at 2pm today, 2,100 ft.

Presumably landing? I think that may be the one that was surveiling
Kaliningrad this morning. A German-based NATO E-3A has taken over, flying
figure-of-8 circuits over Lublin.

On 03/03/2022 16:21, Roland Perry wrote:
> An RC135W 10 miles out at 2pm today, 2,100 ft.

I have noticed what looked like some of the smaller ELINT aircraft as well.

MB <MB@nospam.net> wrote:
> On 03/03/2022 16:21, Roland Perry wrote:
>> An RC135W 10 miles out at 2pm today, 2,100 ft.
>
> I have noticed what looked like some of the smaller ELINT aircraft as well.

There’s something which is identified as a Bombardier Challenger 650,
callsign CL60, but with no registration and no other details, which
regularly flies up and down there. Could be anything, really.

Sam

--
The entity formerly known as Sam.Wilson@ed.ac.uk
Spit the dummy to reply

Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> wrote:
> MB <MB@nospam.net> wrote:
>> On 03/03/2022 16:21, Roland Perry wrote:
>>> An RC135W 10 miles out at 2pm today, 2,100 ft.
>>
>> I have noticed what looked like some of the smaller ELINT aircraft as well.
>
> There’s something which is identified as a Bombardier Challenger 650,
> callsign CL60, but with no registration and no other details, which
> regularly flies up and down there. Could be anything, really.
>

Perhaps Artemis?
<https://www.defensenews.com/land/2021/05/27/looking-at-high-speed-isr-jet-capability-us-army-deploys-demonstrator-to-europe/>

In message <svqqov$ins$1@dont-email.me>, at 16:35:43 on Thu, 3 Mar 2022,
Recliner <recliner.usenet@gmail.com> remarked:
>Roland Perry <roland@perry.co.uk> wrote:
>> In message <Y7pTIcpq21HiFArM@perry.uk>, at 12:06:02 on Wed, 2 Mar 2022,
>> Roland Perry <roland@perry.co.uk> remarked:
>>> In message <svm669$naj$1@dont-email.me>, at 22:19:53 on Tue, 1 Mar
>>> 2022, Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>>> Roland Perry <roland@perry.co.uk> wrote:
>>>>> In message <svl0ir$fl9$1@dont-email.me>, at 11:38:03 on Tue, 1 Mar 2022,
>>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>>>>
>>>>>> When the Mildenhall KC-135s do racetracks over the North Sea there are
>>>>>> rarely any other aircraft visible in attendance.
>>>>>
>>>>> Do you mean "in attendance and being refuelled"?
>>>>
>>>> I mean visible on FlightRadar24. There are often F-15s, Typhoons and Hawks
>>>> shown on FR24 but miraculously they never seem to go near either the
>>>> KC-135s or the other tankers while they’re running the racetrack
>>>>patterns.
>>>>
>>>>> FWIW those tankers frequently fly literally over my house (+/- 50m) and
>>>>> the base commander keeps his hand in flying one from time to time. Why
>>>>> do I know that - I had lunch with him a few years ago. Hopefully I won't
>>>>> now get a visit from any black helicopters (they prefer to use Ospreys)
>>>>>
>>>>> https://www.youtube.com/watch?v=F9snZJadgkQ
>>>>
>>>> The KC-135s fly over a family member’s house too, but at a considerably
>>>> higher altitude. I’ve not seen an Osprey yet.
>>>
>>> Looking at FlightRadar24 just now there's an Osprey cruising across
>>> central Cambs at 3,700ft. Can't see any tankers; they'd be at whatever
>>> height that kind of aircraft is, 10 miles from landing.
>>
>> An RC135W 10 miles out at 2pm today, 2,100 ft.
>
>Presumably landing?

Yes, I was just trying to find a data point for the height of an
aircraft approximately that size at 10miles out.

> I think that may be the one that was surveiling Kaliningrad this
>morning. A German-based NATO E-3A has taken over, flying figure-of-8
>circuits over Lublin.

--
Roland Perry

On Thu, 3 Mar 2022 16:21:49 +0000, Roland Perry <roland@perry.co.uk>
wrote:

>In message <Y7pTIcpq21HiFArM@perry.uk>, at 12:06:02 on Wed, 2 Mar 2022,
>Roland Perry <roland@perry.co.uk> remarked:
>>In message <svm669$naj$1@dont-email.me>, at 22:19:53 on Tue, 1 Mar
>>2022, Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>>Roland Perry <roland@perry.co.uk> wrote:
>>>> In message <svl0ir$fl9$1@dont-email.me>, at 11:38:03 on Tue, 1 Mar 2022,
>>>> Sam Wilson <ukr@dummy.wislons.fastmail.co.uk> remarked:
>>>>
>>>>> When the Mildenhall KC-135s do racetracks over the North Sea there are
>>>>> rarely any other aircraft visible in attendance.
>>>>
>>>> Do you mean "in attendance and being refuelled"?
>>>
>>>I mean visible on FlightRadar24. There are often F-15s, Typhoons and Hawks
>>>shown on FR24 but miraculously they never seem to go near either the
>>>KC-135s or the other tankers while they’re running the racetrack patterns.
>>>
>>>> FWIW those tankers frequently fly literally over my house (+/- 50m) and
>>>> the base commander keeps his hand in flying one from time to time. Why
>>>> do I know that - I had lunch with him a few years ago. Hopefully I won't
>>>> now get a visit from any black helicopters (they prefer to use Ospreys)
>>>>
>>>> https://www.youtube.com/watch?v=F9snZJadgkQ
>>>
>>>The KC-135s fly over a family member’s house too, but at a considerably
>>>higher altitude. I’ve not seen an Osprey yet.
>>
>>Looking at FlightRadar24 just now there's an Osprey cruising across
>>central Cambs at 3,700ft. Can't see any tankers; they'd be at whatever
>>height that kind of aircraft is, 10 miles from landing.
>
>An RC135W 10 miles out at 2pm today, 2,100 ft.
>
It is unusual not to see one or two over/around the UK at some time of
the day. The nearest ATM has just landed at Geilenkirchen after two
two or three circuits West of Hamburg; currently 7 military aircraft
are showing up over the UK, two RAF helicopters, 3 USA and 2 RAF
aeroplanes.