So it uses captured German die Glocke technology does it?Richard Anderson wrote: ↑19 Feb 2021 16:49Oh, that's right I forgot USS Behemoth is also capable of 40 knots and is inertialess. Never mind.

Well, at least there'd be room for it...
So it uses captured German die Glocke technology does it?Richard Anderson wrote: ↑19 Feb 2021 16:49Oh, that's right I forgot USS Behemoth is also capable of 40 knots and is inertialess. Never mind.
Awwe, I understand guys. Yesterday's formula-based discussion tired you out and you need to rest and fall back to "man on the street" intuition. That's okay, yesterday was fun and you've earned a mental respite.T. A. Gardner wrote: ↑19 Feb 2021 18:52So it uses captured German die Glocke technology does it?Richard Anderson wrote: ↑19 Feb 2021 16:49Oh, that's right I forgot USS Behemoth is also capable of 40 knots and is inertialess. Never mind.
No, I just enjoy tossing in a bit of snark and sarcasm from time to time. It lightens the mood when the conversation starts getting ugly.TheMarcksPlan wrote: ↑19 Feb 2021 23:01
Awwe, I understand guys. Yesterday's formula-based discussion tired you out and you need to rest and fall back to "man on the street" intuition. That's okay, yesterday was fun and you've earned a mental respite.
Well snark on. Perhaps you can see why it's easy to read that as "there's no way this ship could do 40kn on 3mil HP" but as that wasn't your intent...T.A. Gardner wrote:No, I just enjoy tossing in a bit of snark and sarcasm from time to time.
No:Terry Duncan wrote:18" gun with a RoF of in excess of 10rpm
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No:Terry Duncan wrote:A draught of 95ft when suited
No:Terry Duncan wrote:a high length to beam ratio
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No:Terry Duncan wrote:plus presumably variable sized propellors?
TheMarcksPlan wrote: ↑19 Feb 2021 23:01
Reverse
The ship probably also has a few relatively small forward propellers that would only be used for reverse and maneuver. These would be, say, 15ft diameter and therefore a small contribution to the ship's friction drag. In normal times they'd windmill and most of their additional friction would be captured by using their electric motors as dynamos to feed the ship.
By putting these smaller propellers at maximum depth (tips 95ft below waterline) they'd operate in ambient water pressure ~4.8x higher than at 20ft.
The cavitation limit for these 15ft propellers would be ~570 RPM (taking ~625k HP). Thus 4 small propellers could use nearly all the ship's horsepower rapidly to stop it or - in conjunction with the normal propellers - to drive it reverse. Of course these propellers could also help with maneuver via asymmetric thrust. Again the small propellers have low propulsive efficiency but we're not using them for long-range cruise.
As the above posts make clear, use of propellers at different critical points based on distribution of electrical generating capacity. Not the remotest suggestion that propellers change size/pitch. Where'd you get that?TheMarcksPlan wrote: ↑19 Feb 2021 23:01Electric propulsion enables rapid distribution of the ship's HP to its various propellers. While steaming in battle and at optimal range, we wouldn't need to maintain speed faster than the enemy battle line - else we're shortly out of optimal range.
Instead of slowing down all the propellers to match, say, 27kn enemy speed, we'd run only ~half propellers on the centerline and shut down those in the the wings. It's less fuel-efficient but negligible given a battle's duration. Why do this? Because with the wing propellers inert they can be rapidly spooled up for maneuver: For a quick turn to port, go full throttle forward on the starboard engines and full reverse port. This should provide an excellent turning radius for a large ship. Here the ship's high B:L ratio helps - the outer props have a large moment arm for creating rotational torque.
So, pre-proximity fused AA functionally useless, rather like the supposedly AA capable 18.1" on Yamato.
Deeper than many seas where a ship will possibly be needed.
With that length to beam ratio a high speed is very difficult to obtain, which is why the Iowa's had such a long thin bow and such a high power plant output, and even then didnt make 33kts yet alone 40kts.
I has just curious as such a massively variable draught hull and massive speed ambitions presumably isnt relying on 15ft propellors for actual general movement?TheMarcksPlan wrote: ↑18 Feb 2021 12:08No:Terry Duncan wrote:plus presumably variable sized propellors?
TheMarcksPlan wrote: ↑19 Feb 2021 23:01
Reverse
The ship probably also has a few relatively small forward propellers that would only be used for reverse and maneuver. These would be, say, 15ft diameter and therefore a small contribution to the ship's friction drag. In normal times they'd windmill and most of their additional friction would be captured by using their electric motors as dynamos to feed the ship.
By putting these smaller propellers at maximum depth (tips 95ft below waterline) they'd operate in ambient water pressure ~4.8x higher than at 20ft.
The cavitation limit for these 15ft propellers would be ~570 RPM (taking ~625k HP). Thus 4 small propellers could use nearly all the ship's horsepower rapidly to stop it or - in conjunction with the normal propellers - to drive it reverse. Of course these propellers could also help with maneuver via asymmetric thrust. Again the small propellers have low propulsive efficiency but we're not using them for long-range cruise.
As the above posts make clear, use of propellers at different critical points based on distribution of electrical generating capacity. Not the remotest suggestion that propellers change size/pitch. Where'd you get that?TheMarcksPlan wrote: ↑19 Feb 2021 23:01Electric propulsion enables rapid distribution of the ship's HP to its various propellers. While steaming in battle and at optimal range, we wouldn't need to maintain speed faster than the enemy battle line - else we're shortly out of optimal range.
Instead of slowing down all the propellers to match, say, 27kn enemy speed, we'd run only ~half propellers on the centerline and shut down those in the the wings. It's less fuel-efficient but negligible given a battle's duration. Why do this? Because with the wing propellers inert they can be rapidly spooled up for maneuver: For a quick turn to port, go full throttle forward on the starboard engines and full reverse port. This should provide an excellent turning radius for a large ship. Here the ship's high B:L ratio helps - the outer props have a large moment arm for creating rotational torque.
Here the ship's high B:L ratio helps
Terry Duncan wrote: ↑20 Feb 2021 12:57So, pre-proximity fused AA functionally useless, rather like the supposedly AA capable 18.1" on Yamato.
Deeper than many seas where a ship will possibly be needed.
With that length to beam ratio a high speed is very difficult to obtain, which is why the Iowa's had such a long thin bow and such a high power plant output, and even then didnt make 33kts yet alone 40kts.
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I am just curious as such a massively variable draught hull and massive speed ambitions presumably isnt relying on 15ft propellors for actual general movement?TheMarcksPlan wrote: ↑18 Feb 2021 12:08No:Terry Duncan wrote:plus presumably variable sized propellors?
TheMarcksPlan wrote: ↑19 Feb 2021 23:01
Reverse
The ship probably also has a few relatively small forward propellers that would only be used for reverse and maneuver. These would be, say, 15ft diameter and therefore a small contribution to the ship's friction drag. In normal times they'd windmill and most of their additional friction would be captured by using their electric motors as dynamos to feed the ship.
By putting these smaller propellers at maximum depth (tips 95ft below waterline) they'd operate in ambient water pressure ~4.8x higher than at 20ft.
The cavitation limit for these 15ft propellers would be ~570 RPM (taking ~625k HP). Thus 4 small propellers could use nearly all the ship's horsepower rapidly to stop it or - in conjunction with the normal propellers - to drive it reverse. Of course these propellers could also help with maneuver via asymmetric thrust. Again the small propellers have low propulsive efficiency but we're not using them for long-range cruise.
As the above posts make clear, use of propellers at different critical points based on distribution of electrical generating capacity. Not the remotest suggestion that propellers change size/pitch. Where'd you get that?TheMarcksPlan wrote: ↑19 Feb 2021 23:01Electric propulsion enables rapid distribution of the ship's HP to its various propellers. While steaming in battle and at optimal range, we wouldn't need to maintain speed faster than the enemy battle line - else we're shortly out of optimal range.
Instead of slowing down all the propellers to match, say, 27kn enemy speed, we'd run only ~half propellers on the centerline and shut down those in the the wings. It's less fuel-efficient but negligible given a battle's duration. Why do this? Because with the wing propellers inert they can be rapidly spooled up for maneuver: For a quick turn to port, go full throttle forward on the starboard engines and full reverse port. This should provide an excellent turning radius for a large ship. Here the ship's high B:L ratio helps - the outer props have a large moment arm for creating rotational torque.
This interesting comment;
Here the ship's high B:L ratio helps
6 - 1 is not a high B:L ratio, it is roughly that of a WWI dreadnought and nothing like the roughly 10:1 the Japanese needed for their cruisers to reach 35kts pre-WWII. Most navies found 7:1 or 8:1 the minimum needed for obtaining high speeds. Once you drop below this, and certain hull forms, you need vastly more power to just move the ship. It is almost impossible to achieve both high speed and high maneuverability as the two require different hull forms and ratios.
Have you ever tried to use any of the ship design programs out there to create what you are proposing?
So, pre-proximity fused AA functionally useless, rather like the supposedly AA capable 18.1" on Yamato.
Deeper than many seas where a ship will possibly be needed.
With that length to beam ratio a high speed is very difficult to obtain, which is why the Iowa's had such a long thin bow and such a high power plant output, and even then didnt make 33kts yet alone 40kts.
I am just curious as such a massively variable draught hull and massive speed ambitions presumably isnt relying on 15ft propellors for actual general movement?TheMarcksPlan wrote: ↑18 Feb 2021 12:08No:Terry Duncan wrote:plus presumably variable sized propellors?
TheMarcksPlan wrote: ↑19 Feb 2021 23:01
Reverse
The ship probably also has a few relatively small forward propellers that would only be used for reverse and maneuver. These would be, say, 15ft diameter and therefore a small contribution to the ship's friction drag. In normal times they'd windmill and most of their additional friction would be captured by using their electric motors as dynamos to feed the ship.
By putting these smaller propellers at maximum depth (tips 95ft below waterline) they'd operate in ambient water pressure ~4.8x higher than at 20ft.
The cavitation limit for these 15ft propellers would be ~570 RPM (taking ~625k HP). Thus 4 small propellers could use nearly all the ship's horsepower rapidly to stop it or - in conjunction with the normal propellers - to drive it reverse. Of course these propellers could also help with maneuver via asymmetric thrust. Again the small propellers have low propulsive efficiency but we're not using them for long-range cruise.
As the above posts make clear, use of propellers at different critical points based on distribution of electrical generating capacity. Not the remotest suggestion that propellers change size/pitch. Where'd you get that?TheMarcksPlan wrote: ↑19 Feb 2021 23:01Electric propulsion enables rapid distribution of the ship's HP to its various propellers. While steaming in battle and at optimal range, we wouldn't need to maintain speed faster than the enemy battle line - else we're shortly out of optimal range.
Instead of slowing down all the propellers to match, say, 27kn enemy speed, we'd run only ~half propellers on the centerline and shut down those in the the wings. It's less fuel-efficient but negligible given a battle's duration. Why do this? Because with the wing propellers inert they can be rapidly spooled up for maneuver: For a quick turn to port, go full throttle forward on the starboard engines and full reverse port. This should provide an excellent turning radius for a large ship. Here the ship's high B:L ratio helps - the outer props have a large moment arm for creating rotational torque.
Here the ship's high B:L ratio helps
A firing cycle of 20 seconds at "high-elevation" for an "18in gun"?Terry Duncan wrote: ↑20 Feb 2021 13:01So, pre-proximity fused AA functionally useless, rather like the supposedly AA capable 18.1" on Yamato.
Would need a very large magazine! And some very large gunners.Richard Anderson wrote: ↑20 Feb 2021 16:54A firing cycle of 20 seconds at "high-elevation" for an "18in gun"?
Then there's the moment of inertia to overcome when maneuvering. You'd need a lot of rudder(s) to change course simply because of the moving mass of the ship. Same goes for acceleration and deceleration.Terry Duncan wrote: ↑20 Feb 2021 13:01
6 - 1 is not a high B:L ratio, it is roughly that of a WWI dreadnought and nothing like the roughly 10:1 the Japanese needed for their cruisers to reach 35kts pre-WWII. Most navies found 7:1 or 8:1 the minimum needed for obtaining high speeds. Once you drop below this, and certain hull forms, you need vastly more power to just move the ship. It is almost impossible to achieve both high speed and high maneuverability as the two require different hull forms and ratios.
Have you ever tried to use any of the ship design programs out there to create what you are proposing?
A firing cycle of 12 seconds....Richard Anderson wrote: ↑20 Feb 2021 16:54A firing cycle of 20 seconds at "high-elevation" for an "18in gun"?Terry Duncan wrote: ↑20 Feb 2021 13:01So, pre-proximity fused AA functionally useless, rather like the supposedly AA capable 18.1" on Yamato.