Originally posted by ropebag
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EPV for naval service
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In terms of landing craft they usually start with LCVP, then go up to LCM and finally LCU. After that it is a landing ship.
LCVP
most common design used by Dutch and RN
https://products.damen.com/en/ranges...personnel-1604
LCM
(similar to that mounted on HMNZS Canterbury, no well deck!
https://military.wikia.org/wiki/LCM-1E
Italian LCM
https://www.vittoria.biz/en/c-828-landing-craft-mtm/
LCU
Damen version for the Dutch but RN Mk10 is very similar.
https://products.damen.com/en/ranges...t-utility-3607
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Originally posted by DeV View PostAnd then you need a well deck and probably another few thousand tonnes displacement
Hadr equipment wouldn't be a part of her everyday pay load, although she should have mobile equipment to move on board weights. Cranes would have the SWL capacity to 20 tonnes at least. The LCVP type should if possible dry load and be lowered to launch. The equipped Hadr role should include portable equipments useful in disaster areas and include JCB or CAT equipment to about 9/10 Tonnes to be discharged by Crane/Quay wall ramp from ship. Any other increase in capability in a particular role removes flexibility and is a different ship. All capabilities must be clearly seen and designed in.
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Originally posted by ancientmariner View PostMy view of the MRV is that multi role is predominant-can be command platform-can move troops and equipment-can accept interaction with helicopters-can supply to own ships/others-can tow to her tonnage standards-can be a HADR assist vessel including evac/medical when equipped-can deliver/manufacture FW- can take/deliver shore power-can support/defend in its location.
Hadr equipment wouldn't be a part of her everyday pay load, although she should have mobile equipment to move on board weights. Cranes would have the SWL capacity to 20 tonnes at least. The LCVP type should if possible dry load and be lowered to launch. The equipped Hadr role should include portable equipments useful in disaster areas and include JCB or CAT equipment to about 9/10 Tonnes to be discharged by Crane/Quay wall ramp from ship. Any other increase in capability in a particular role removes flexibility and is a different ship. All capabilities must be clearly seen and designed in.
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Originally posted by EUFighter View PostWhy did the USN have such ships in the first place? Well they had plenty of destroyer escorts and not a lot for them to do in the Pacific. While we all focus on the big actions like Tarawa, Makin, Iwo Jima there were many much smaller islands that had to be attached and did not need a full on assault. But this was a time of learning in amphibious warfare and many of the ships types from that time are no longer to be found in service.
Some comments brought up the Absolon class, it is close to what the APD's had with the exception it primary assault means would be via helicopter as it does not carry landing craft like a LCVP or LCM. But it weapons fit make it much better suited to the proposed mission than that in the article (SPY radar, SM missiles etc). It is likely that we could get 2x MRV's and 2x Absolon class vessels for the price of one of the proposed LRPV's.
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Originally posted by ancientmariner View PostMy view of the MRV is that multi role is predominant-can be command platform-can move troops and equipment-can accept interaction with helicopters-can supply to own ships/others-can tow to her tonnage standards-can be a HADR assist vessel including evac/medical when equipped-can deliver/manufacture FW- can take/deliver shore power-can support/defend in its location.
Hadr equipment wouldn't be a part of her everyday pay load, although she should have mobile equipment to move on board weights. Cranes would have the SWL capacity to 20 tonnes at least. The LCVP type should if possible dry load and be lowered to launch. The equipped Hadr role should include portable equipments useful in disaster areas and include JCB or CAT equipment to about 9/10 Tonnes to be discharged by Crane/Quay wall ramp from ship. Any other increase in capability in a particular role removes flexibility and is a different ship. All capabilities must be clearly seen and designed in.
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Originally posted by na grohmiti View PostThis is already the case, Naval vessels have enough generating capacity onboard to power a small town.
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I'm no marine engineer, but it's a figure that is frequently quoted.
I dont understand what you mean by turbine electric propulsion.
Do you mean that a steam turbine is driving a generator, which propels the ship using motors instead of a standard shaft from the engine gearbox?
Another option is an industrial standard generator, usually the same size as a 40 foot container. It provides all the power heavy industry needs when they go off grid during peak loads.
But the standard genny set up on most OPV does the same thing.For now, everything hangs on implementation of the CoDF report.
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Originally posted by na grohmiti View PostI'm no marine engineer, but it's a figure that is frequently quoted.
I dont understand what you mean by turbine electric propulsion.
Do you mean that a steam turbine is driving a generator, which propels the ship using motors instead of a standard shaft from the engine gearbox?
Another option is an industrial standard generator, usually the same size as a 40 foot container. It provides all the power heavy industry needs when they go off grid during peak loads.
But the standard genny set up on most OPV does the same thing.
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Originally posted by na grohmiti View PostI'm no marine engineer, but it's a figure that is frequently quoted.
I dont understand what you mean by turbine electric propulsion.
Do you mean that a steam turbine is driving a generator, which propels the ship using motors instead of a standard shaft from the engine gearbox?
Another option is an industrial standard generator, usually the same size as a 40 foot container. It provides all the power heavy industry needs when they go off grid during peak loads.
But the standard genny set up on most OPV does the same thing.
I am not talking about your basic genny. I am talking about the prime mover, the thing moving the ship through the water being electric,. This is _not_ your bulk standard genny.
Look at HMS Queen Elizabeth (the curent one) several diesels and 2 GTs providing electricity to drive the electric motors that drive the 2 shafts. Queen Mary has a similar propulsion, as does Juan Carlos. Your gennies do not nearly have the same amount of power as the engines actually propelling the ship. So I am suggesting that the ship be diesel electric driven so that she has something like 10 MW generating capacity instead of maybe 2MW.
So while every waship has a certain amount of generating power it is only a small amount compared to the power of the propulsion diesels. In a diesel electric drive all the power of the prime movers is available for providing electricity. In my example USS Lexington (CV-2) provided the City of Tacoma not with power from her gennies, but from her main propulsion.Last edited by Graylion; 6 June 2020, 01:44.
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The TE system did not go out of use due to naval treaty restrictions, many vessels had this type of propulsion installed that were built during WW2. Most famous would be the Buckley class destroyer escorts (the one from the film The Enemy Below). The main reason the USN switched to steam turbine power for their first new build battleship since they stopped build at the end of WW1 (Carolina class) was the advances in turbine technology. They started to fit high pressure turbine systems (high but not crazy German high). This allowed for a reduction on size for the same power. On the Destroyer Escort side, the challenges of war production eventually saw the replacement of the TE system with the now widely used diesel electric system, even if the former was vastly superior for hunting subs.
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