If the Dwarf Cannon never existed, creating Cannonballs for Sailing would've given 15 per bar and ship combat would be in a better state.

As the title states, because the Dwarf Cannon is so strong, a Steel Bar only makes 4 cannonballs and Jagex thought they had to keep this the same.

Imo Steel Cannonballs should be kept as a separate item for only the Dwarf Cannon and all other Cannonballs for Ship Combat should be separate. You should definitely get way more per bar, probably closer to 15 or so like you get with Nails.

Ship Combat definitely needs a lot more improvements than just this but I think it's a good place to start. Don't let the Dwarf Cannon influence how it would've been if it wasn't already just 4 per bar. They would probably also be smelted way faster too.

Side point about Ship Combat: I didn't play the beta or read too much into Sailing prior to release because I wanted to experience it for the first time upon release, but I was under the impression that Monsters in the sea would take next to no damage from Magic/Ranged attacks and that Ship Combat (Ship Cannons, Mounted Ballistas, Spears, etc) was going to be the ONLY way to really kill things and I thought that was kind of cool.