Chris has been thinking and would like to prpose these ideas...
1) Abillity to upgrade certain spots
a: Cargo Holds - Each one can hold up to 30 KG each
b: Cannons - ... duh
c: Speed- add more sails with cloth to get a faster speed/manuverabilty
d: Armor- add iron to the ships to make em withstand more shots.
2) Burning/Boarding
a: Torches/Fire Magic will slowly destroy the ship unless they use watering ans on the flames
b: Make a lil bridge craftable it wieghs 15 kg and can be lowered to another ship so you can board it!