I have a few thoughts regarding those.
Cannons
Dragonfire Carronades
- Hits immobile ships harder than Iron Carronades would
- Good against docked ships
- When on a dreadnaught-class ship, counters rams extremely well
- Useless against moving ships as it would involve damage-trading
Overall worse than the Iron Carronades as it only inflicts slightly more damage in niche situations for a decrease in reload time, range, and increase in weight.
Iron Carronades
- Most short-time damage output of all cannons
- Has low range
- This downside can be nullified by learning how to aim
- Usage of hit-and-run tactics can also nullify this downside (unlike with Dragonfire Carronades)
The best cannons in the entire game by far as it pairs extremely well with the corvette-class ship meta.
Heavy Iron Cannons
- Balanced cannons
Best for players lacking in aiming skills as it inflicts a good amount of damage all while having a good range.
Iron Culverins
- Extremely high range
- High range that is realistically only viable for surprise attacks
- Requires an extreme level of aiming skills to make the most out of it
- Great when used on and against dreadnaught-class ships.
- Shorter reload time
- Reduced penalty when missed, great to learn how to aim
- Moderate damage
- Underwhelming when compared to titans (Iron Carronades, Heavy Iron Cannons), but still an upgrade from Heavy Cannons
Overall the potentially strongest cannons of the game thanks to their amazing range and average damage, unfortunately requires an unbelievable amount of skill to use.
tl;dr the “Potential Cannons”
Siege Weaponry
I made a wole topic regarding those, reading through the replies will give you a good idea of which is best for what situation.