Favoring cannons I know the different shots that they have and for what specific purpose you need them. its also importance since they also affect how you PVP or defend yourself in the game.
1. Normal shot/duel shot
Durability damage dealers. Duel Shot type cannons are normally high-penetration, short-ranged, slow reload.
Dual Shot Ship Skill "armor piercing" can cause "great leaking" to the target. (leaking causes lower armor + great leaking can't be healed with buckets)
It can cause fires on targets. The more slots you have flame shots with, the more frequent cause fire.
Not effective when it is raining. Flame shot can occasionally cause explosion which reduces ammunition.
Flame shot skill "armor deterioration shot" is a passive skill to decrease armor of the target during the battle. (only goes down to half. no way to heal)
Aide skill "Enhance Flame Shot" can increase possibility of fire and reduces more water on fire.
3. Smoke shot
can cause smoking on targets. can only recovered by an item which certain NPCs drop or by time. Critical hit cause smoking at 100%.
Ship Skill "Special smoke shot" can cancel effective active skills of the target on critical hit.
Aide Skill "Enhance smoke shot" can increase the possibility of smoking and reduces food of the target.
4. Chain shot
Damages ship parts. High bursts can cause damages to sails and the steer of a target.
Critical hit cause damages on sails or the steer at 100%.
It also halve the sailing speed when critical shot hit on the peak. (good for PKers)
5. Grape shot
Damage to sailors WHEN the durability of the target is less than half.
Critical hit can reduce vigor of the target.
Ship Skill "Burst shot" can cause chaos on the target (stronger version of confusion) at low possibility (critical hit causes at 100%)
Aide skill "Enhance Grape shot" can reduce vigor of the target even without a critical hit.