Thanks, hope things continue to go aight here. To get back on track...
Are naval warships in any of the versions of Cataclysm?
There's a military amphibious lander in both versions if I recall, the DUKW or something like that? Other than that, not much. I've been tempted to add something in that vein to Tankmod: Revived but I've yet to find a type of boat to base it off of that is:
1. Reasonably common in US Navy use in terms of number made. At least 50 made, ideally 100+
2. Has at least one 25mm autocannon in its listed armament since that's what I'd want it to help showcase, maybe 30mm if I'm willing to split the autocannon into 25mm and 30mm like I have for 105mm vs. 120mm, but it's hard to justify doing that since 105mm is already only really excused because there's just barely enough different sorts of armored vehicles in the mod to excuse the split.
3. Is small enough that the player would be reasonably justified in being able to crew, and so that a realistic-looking mockup of it in the vehicle system won't look way too huge to be able to travel by river.
Even patrol boats seem likely to fall afoul of problems 1 and 3, Mark IVs for example have 25mm autocannons so no need to worry about ammo split, but quick wiki-fu says there's only 12 of them and they're big enough to have a crew of 10. So even patrol boat size is pushing the limits of what might be reasonable to drop in the player's lap and expect to treat as a floating deathmobile.