I was poking around Internet as usual when i found this. When I fist came basically this design was what i wanted to build (A SWATH submersible with high surface speed), as a larger dry alternative to the SEAL submersible we use in Sweden. Back then it was shot down because ppl were not sure I would be able to reach 40 knots... guess what the stated speed of this design is precisely 40 knots so that one seems satisfied and that draft looks even better than I expected.

So basically I'm going for a larger militarized version of it for use as a CB90 in an archipelago environment.

Diving is something that would be very useful in and archipelago defense situation (almost guerrilla style as my old unit operates ) when the airspace is not in friendly control. Diving can then be used to hide boats when units are occupying islands, it can be used as an evasive action against helicopters (if the dive is fast enough). It can be used to avoid being detected by UAVs or satellite photos or for stealthy ex-filtration or infiltration.

During a clasical Stockholm Archipelago defense scenario the boats are our lifelines if we lose them we become stranden on a single island ready to be swept away. (Sure we also have canoes and combat swimming at our disposal) but that makes us unable to bring along hellfire (that we use against ships), SAM's so (so the enemy becomes unopposed in the sky) and mortars (so we cant support island assaults or use harassing fire on enemy occupied islands)


So the question is: How would you do something like the linked boat so that it can operate well in a military role between 30000 of these. (Witch just happens to be a perfect deathtrap for troops not trained to fight in that environment

http://stiddmil.com/public/MRCC/

I think I'd use this. 40 knots I simply do not need.

There would only be certain places that they can be used at certain depths, such is the topography of the ocean floor. Other forces with a good knowledge of the ocean floor would be able to guess routes. Because of this, they may not be as effective as what they seem.

I can't see any flaws with it but that's just me. Agree with Kyiv though, 40 knots is overkill.

Not too useful in island-chains.

Deepwater-ops, "Go-fasts", maybe. But it gets pretty hard to rationalize a boat that does 40 on water when it's small enough to be airlifited most of the way, especially if it requires you to compromise where it can land.

Nope, the solution is obviously in submarines that come with hovercraft-skirts so they don't even need dry-docks.

Alternately, strap an ICBM to the minisub, so it can fly over the defenseless landmasses on a ballistic arc.

If I come up in such a situation I'd just keep my ships far away from those landmasses and wait for the subs to come out.

Speed is of the essences in my units operations, it’s the other way we stay alive. Even the resupply ferries are fast planning designs (which means that we prioritize speed so much, that we actively sacrifice loading capacity for speed in a vessel that built for hauling load, though it might be added that they are a bit slower than the CB90) That being said 40 knots is not a magical number, it can easily be 35 knots, but lower than 30 and we are approaching a deal breaker.

Some other examples of the need for speed in archipelago warfare:

The in use submersible SEAL carrier also does close to 40 on the surface.

And when we upgraded the CB90 we made them even faster (which required some thinking because of the extra weight of the added ballistic protection)

There is one other country with an equivalent archipelago to ours, and that is Finland, they have their own fast transport the Jurmo (Norway have sort of similar terain with the fjords and they use the CB90)

Airlifting is not an option when we fight in the archipelago, because we don't rule the sky, we contest it with SAMs. We don’t “control” the archipelago in a strict sense we only make it a damn dangerous area to run ships or aircraft trough. Imagine it more as pre prepared, well equipped guerrilla warfare with the goal of dissuading sea access to our capital. It was a part of the invasion defense against the Soviet Union, and that entire defense plan was based on the fact that we could never stop the Soviet Union if they really wanted to stomp us, but we could be a target that is worth less than it costs, especially since we were “neutral”. (Imagine the defense plan as a modern version of the finish winter war) That why we don't use helicopters, they would be shot out of the sky (sure I trained with helicopters quite a bit, but that is based on how we operate abroad)

90% of the time when moving these vessels will be operating on the surface and then moving slow is not an option, it has to be fast to even keep up with the rest of the battalion but mainly to be able to out maneuver, or out run pursuers, and to be able to quickly leave an island which has been used to launch SAM’s, Hellfire’s or mortar shells. (Or if a forward OP is discovered)

The most useful features thanks to the submersible design would actually be the ability to hide the boat in a good way when we are hiding on an island (which, is almost all the time so it should be a really useful feature), and I can also see semi-submerged sneaking being used quite a bit (only the snorkel and the bridge over the waterline) fully submerged movement is a good added capability that certainly will be used those last 10% but it will not be how we regularly move around.

On to some engineering and capabil
ity questions:
Would it be realistically possible to “hinge” the two floating/ballast hulls so they can be raised to the sides? The goal of this would be to reduce “draft” when underwater, semi submerged and when making beach landings.

What would be the downsides to using larger electric engines and using them not only when submerged but also as propulsion when surfaced? The boat would of course have diesel engines to give juice to the engines when air is available (The electric engines would probably drain the batteries in 30 min’s if they were used full burn without help of the diesels). The goal with this sort of arrangement would be to easier facilitate “hinged” hulls.

I am also thinking about possible other versions (with the 10 man troop compartment removed).

Mine laying version (we use smart mines quite a bit).

Weapon carrying variants not sure which but some among these SAM, mortar, light anti ship missile and auto cannon.

Medical version, that’s one funky ambulance.

Possibly one with a small pressure chamber for use by combat divers and underwater saboteurs.

How good would a AWACS be at detecting a small surface vessel in an archipelago environment? Should the vessel be shaped to reduce detection risk?


I envision this boat being used by a island nation surrounded on all sides by a massive archipelago (or by Sweden that suddenly decides to burn allot of money on the amphibious forces)

Then we have accomplished our goal of denying access, we certainly won’t attack big ships in open waters, that would be suicide.