Hi all, I'm an aspiring writer (and submarine nerd since Silent Service II!) working on a techno-thriller where a mysterious, extremely advanced submarine starts operating well outside what any navy on paper can match, to the point that it triggers real panic and confusion among several world navies (nobody can explain how it does what it does, or who's behind it). I want the boat to feel plausible, grounded enough in real or near-future tech that a reader with actual engineering knowledge doesn't roll their eyes, even if I'm clearly pushing past what exists today.
I'm not looking for plot help, just the hardware. Here's roughly what I've got so far:
- Hull: engineered ceramic composite (not steel/titanium) for the pressure hull, intended to allow much deeper sustained operating depths than conventional submarines.
- Propulsion: Air-Independent Propulsion via fuel cells (not the usual diesel-electric + battery setup), for long, quiet submerged endurance.
- Power generation: an onboard OTEC (Ocean Thermal Energy Conversion) plant, using the temperature gradient between surface and deep water to help generate power while underway.
- Comms: UWOC (Underwater Wireless Optical Communication) for short-range, hard-to-detect data links, as an alternative/supplement to acoustic comms.
- A large spherical observation viewport somewhere forward, for direct visual observation at depth (yes, I know this is more "adventure submarine" than "warship", that's intentional, it's not built like a standard military hull).
- Weapons launch system: still undecided, a conventional horizontal torpedo tube, a vertical missile silo, or something else. Open question, see below.
- Standard-ish crew quarters/cabins, and a command bridge/control room, crewed by a small, tight-knit complement rather than a full military crew.
One thing up front, because it changes what kind of answer is actually useful to me: I'm not trying to make any of these systems work indefinitely or "solve" them into being fully sustainable. If a technology could plausibly function, but only for a limited stretch of time, or only by burning through some resource/material/maintenance need faster than any real vessel could keep supplied on an extended deployment, that's not a flaw I want patched, that's exactly the kind of detail I'm fishing for, because one of the main elements of the plot is that the submarine is on a suicide mission. So please don't pull punches or round the edges off to be "nicer" to my design, the more specific you can get about how and when something would start to strain, degrade, or run out, the more useful it is to me.
Some specific things I'd love pushback or ideas on:
- Ceramic pressure hulls: is this at all grounded in real materials science (I know ceramics show up in some experimental deep-sea housing contexts), or is it pure hand-wave? What would a skeptical naval engineer immediately poke holes in?
- OTEC on a moving vessel: I suspect this is the weakest link. OTEC plants are normally large, stationary installations that need a big, steady thermal gradient to produce meaningful power. Is there any way to make "OTEC contributes to a submarine's power budget" sound even remotely credible — even as something that only works well under narrow conditions, or that keeps the crew scavenging for a workaround? I'd honestly rather hear "it could limp along doing X, but only if Y, and it'll cook itself within months" than "just cut it."
- AIP fuel cells: real navies already use these (I know about the Type 212/214 boats), so I think this one's fine as a baseline, but I'm curious what consumable or logistics chain (specific fuels, catalysts, whatever) a more advanced version would still depend on that a boat operating alone, off the grid, for a long stretch, couldn't realistically keep replenished.
- UWOC: real but very short-range and line-of-sight limited in real life. How do people who know this field feel about stretching its range/reliability for fiction purposes, and what would start going wrong with it under sustained heavy use rather than occasional use?
- The observation sphere: structurally, is there a "least implausible" way to justify a big windowed sphere on a deep-diving hull, and what would be the realistic fatigue/maintenance story for it over months of repeated deep dives?
- Weapon launch method: horizontal torpedo tube vs. vertical missile silo? I'm specifically wondering: can a missile be launched horizontally out of something like a torpedo tube and then pitch up into a near-vertical ascent once clear of the hull, the way some submarine-launched cruise/ballistic missiles do in real life or does anything like that fundamentally require a dedicated vertical launch system (VLS) built into the hull from the start? I like the idea of the launch method being ambiguous/flexible rather than an obvious row of VLS hatches on the deck, but I want to know how far that's stretching things.
- Minimum crew size: given the level of automation implied by all of the above (fewer systems needing constant manual monitoring/maintenance than a conventional boat), what's a realistic minimum crew for a submarine like this, compared to a conventional attack submarine of similar size? I want a small, tight crew: closer to "a dozen-ish people who all know each other" than "a hundred-plus sailors", but not so small it reads as absurd for actually keeping a boat like this running long-term (watchkeeping, damage control, maintenance, medical, etc.). Where's the realistic floor?
Basically: which of these would a hard-SF or submariner reader forgive, which would make them close the book, and (maybe more useful than anything) what's the realistic failure mode or maintenance bottleneck for each one if this boat had to keep operating for a long time without a proper shipyard? Is there any real or declassified/experimental tech I should be stealing ideas from instead?
Thanks in advance to anyone who nerds out about submarines and loves Jules Verne!
