Shipbucket

Ah. Strait tubes then. I had been envisioning some sort of rotary magazine internally.
This design doesn't have to haul huge amounts of H₂ and O₂ with it constantly. It can use the reactor to feed the production plant. Smaller volume on the pressure vessels starts adding up into size savings very quickly as I am sure you are well aware. You also don't have to man-rate the compartment as it is in a different pressure hull than the humans. It makes a lot of sense to me.

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This design doesn't have to haul huge amounts of H₂ and O₂ with it constantly. It can use the reactor to feed the production plant. Smaller volume on the pressure vessels starts adding up into size savings very quickly as I am sure you are well aware. You also don't have to man-rate the compartment as it is in a different pressure hull than the humans. It makes a lot of sense to me.[/quote]

I am well aware of submarine design... I cannot tell you why but I have "direct" knowledges.
BTW I am curious to have RP1's feedbacks.

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Hi, As Timothy notes, this sub doesn't need to carry a large amount of H2 or O2. It is only powering the UUVs, and it ended up with a couple of UUVs worth of storage, in case the production plant needed to be shut down.

Internally the pressure hull containing the H2/O2 plant was subdivided into separation and compression, O2 stowage and H2 stowage, with the first being accessible from the submarine proper for maintenance.

In theory one could put all this in the main hull - after all, the requirements of the enclosure for this space (acoustic isolation, high resistance to elevated temperatures and pressures) also apply to the reactor compartment! It was just very *convenient* to put it in a separate hull out of the way. There was also some consideration of modularisation - this unit could be updated as the UUVs changed through life (which they probably would).

RP1

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BTW such a design shows a quite large unit. Which is the diameter of the main hull (I mean the internal pressurized one)? And how meany persons?

One more question: fuel-cells for drones and nuke power for the mother unit??? Why not fuel-cell for both?

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A nuclear plant confers strategic mobility, and in any case is certainly necessary to power the hydrogen/oxygen cracking equipment to fuel the UUVs.

OK, so I wrote a long answer but Youtube crashed my display drivers so I lost it.

Short form: H2/O2 module is 3m by 17.6m. Equipment inside is in acoustic enclosures so takes up more space. We actually thought it was a tight fit. Not necessarily the most efficient arrangement, but this was just a starting point. Remember the aim of concept studies is not to provide the answer, it is to help determine the question that must be asked. PH diameter is 9.4m aft and 6.8m fwd where it is surrounded by the UUVs. Complement is 72. 7 arrangement options were investigated.

Speed was limited to 25knots to keep the size of the NSRP down. Nuclear was chosen for the reasons erik_t noted, as well as evasion and cost (AIP is probably more expensive, I say "probably" because (a) AIP submarines are used for different roles so they are not directly comparable, (b) published submarine costs are suspect as they are "expressions of national will" (especially for export as they can be sold at a loss or subsidised), (c) there aren't any German SSNs or British AIP SSKs so we don't know how much of the cost differential is due to other aspects of the boat). Hybrid propulsion systems with downsized nuclear plants and large batteries/fuel cells continue to crop up in studies at UCL and elsewhere as a method of stopping UK SSNs ending up spherical.

[Edit] The other reason for using an SSN as a basis is endurance. Below some endurance level it will be better to carry big tanks of H2 and O2 rather than renew it. Using current storage technologies, this design was way past that endurance level.

RP1

NB// Drawing changed to correct my borked mast copy-paste.

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I agree with your considerations but please think to real operations: currently submarines missions are shifting from attack & intedictions (likw ww1 and ww2) to strategic platforms (cold war) and nowaday to "special operations" (meaning intelligence and covered actions of Seals and equivalent forces): thus I think that compact size and reduced noise represents a plus for AIP (paying this benefits with shorter endurance and lower speed...)

Another intersting "underwater" topic is connected to sensors and communications: long time ago it was supposed to use laser and other optical devices but, I guess, nothing is really working yet

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On the other hand most SpecOps targets and operations are time critical so being able to deploy at high speed while remaining submerged is a great asset. Their ability to stay on station for months at a time is kinda handy as well.

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I don't think so: the "operators" boarding on (into) the submarine with their equipments when necessary.
Moreover it is very usual to operate very very close to the coast: last studies are taking into account to launch UUV from subs to explore the the river mouths...

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Hi,

This thing is that this:
Tends to negate the need for expensive solutions such as AIP. Operating a submarine in enemy coastal waters is not something one would do by choice. AIP in this respect is similar to specialist mine countermeasures vessels - the latter are very complicated and expensive, and are severely constrained in any other kind of operations (some minehunters have an maximum speed of advance in the open ocean of a whopping 7 knots). But in the end they may both be rendered unnecessary by doing things in a different way - by using autonomous vehicles. I would note that that is the focus of the US Navy's UUV Master Plan.

Of course, there are plenty of other things AIP submarines are good for. For regional and coastal navies who need anti-access capabilities, for example. The one area of littoral operations UUVs don't help with is special forces delivery - but stand-off methods can potentially be used to do that from SSNs.

The communications issue is the one developmental technology assumed for this study. Lasers will have a role in communications, but the assumption was that some successful experiments with long range acoustic modems would ultimately converted into a usable system (using some UUVs as relay nodes to extend range) by improvements in processing. Of course, the latter is also true for the opposition... This was seen to be the real yes/no issue regarding armed UUVs. Even the energy problem does not seem to be completely crippling, as long as lower speeds are accepted.

RP1

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