@physichull I'm actually surprised they don't have dry pipe water sprinkler that can be connected to fire pumps for just this kind of event. But having never having been on a warship maybe there is a good reason not to.
Well, as it happens I’m a marine engineer by trade, working for one of the major tanker operators as an Engineering Officer of The Watch on LNG carriers. A big part of my training, and something I have to requalify in and constantly practice is shipboard firefighting, while in my present role I lead one of the ship’s firefighting teams in the event of an engine room fire. I’m by no means an expert on the matter, but I do have some experience from merchant vessels I can offer.
One of the systems we have on civilian vessels similar to what you describe is known as hyper mist. Essentially hypermist uses fresh water from the ship’s freshwater tanks, and through multi-stage centrifugal pumps that can be powered from the vessel’s emergency switchboard, or their own separate Diesel engine, forces water at extremely high pressure through fine solenoid valve operated nozzles over protected spaces (usually main engines, generators, boilers, fuel rooms etc). The water, from the name, comes out as an extremely fine mist, which exponentially increases the surface area of a volume of water, and it’s capacity to absorb heat.
I used this system once on the only ever live fire I’ve ever dealt with in my career, which was when debris left in an exhaust manifold of a generator by contractors destroyed the engine’s turbocharger, leading to lube oil spraying under pressure onto the hot cylinder head and igniting. I happened to be passing the generator room when it happened (luckily I wasn’t actually in there as when the turbo, which was spinning at around 12k RPM disintegrated, it flung shrapnel in a 360° arc around it with enough velocity to embed it in solid steel bulkheads and deck plating) I managed to hit the emergency stop and the hypermist release for that generator, and within seconds of the system activating, a fire that felt intense from 20 metres or so away went out, almost instantly.
....I may have also needed to change my boiler suit as well after that was all over.
That was in the first 2 weeks of my 1st contract as a newly qualified engineer on a container ship.
