I do understand what you want, but i bet POTC Build 13 will give you all that and more, just go to youtube
There are so few real SH5 modders out there and many of them are trying to get SH5 into a shape that the game deserves.
To get a new ship into the game you first need a 3d model that fits into the engine (takes a long time to make)
Because of the structure(i only know the SH 4 part of it) you have to create a ship based on a clone of a submarine. You cant get the damedge model to work 100% because some of the files needed are hardcoded so you have to work around these files and that creates the messed up damedge zones etc.
SH 5 is stil in the werry early stages of modding where most modders stil are trying to work out how to mod the game. Since no official information is around they have to learn this the hard way Trial and error.
Your idea is pretty cool, but i cant se anything like this being worked on before the modders have figured out the game structure. (its a mess of leftover files from atleast SH 4 i personaly gave up on SH 5 when i noticed this junkyard of files)
If you want big sailing ships with big iron cannons and gun smoke, even boarding and raing towns, Just get a copy of POTC, mod it up with Build 13. That will take you 2 hours in total, your idea is atleast 2 years out for the SH 5 platform
Regards
L.T