The sail mod should work just fine now, just unsub- and resubscribe the sails mod and reinstall the new sail mod version version in FTD.

First install odezs sail mod, but you probably have already done that,
So here are all the steps in detail:

-next you go into the main menu.
-select in the main menu the "content" tab.
-scroll down to mods and select create mod.
-then you should end up in the mod menu (white mod list to the top left).
-scroll down in the white modlist until "sail models" shows up at the bottom.
-just click on it, then below another blue transparent selection should show up below.
-scroll down in that new list and click on "materials".
-now another window shows up in the top middle, click on the "sail material" at the very top.
-the material tab should pop up at the right.
-most of that is irellevant but the 4th lowest bar should say "simple block" instead of "full block"
-just click on the black bar it and a dropdown should open.

If it already is "simple block" then you dont need to change anything.

i dont know how to do this

(To make the sail textures load:
Edit the Sails mod,
go to the materials tab and change it from "full block" to "simple block")

These ships totally remind me of this old pirate game i used to play. Great job!!!!

bro that aint no FTD build thats literally a mesh aint no way that looks that good