What is the most effective ship for soloing Divine and Judgement difficulties in Jamestown or does it come down to personal preference and skill?
From the basic ones, I preferred the Charge ship for a long time. However, if you have the Gunpowder, Treason, and Plot DLC (it only cost 75 eurocents when I bought it), there are 4 new, much better ships.
Personally, I prefer the one called
Ghost. It has a decent primary fire with a good coverage.
Secondary fire creates a ghost ship that passes through obstacles and keeps shooting forward and backward. In this mode your primary weapon changes to a short-ranged sword, Excalibur. I found this to be great against bosses, too - the sword does decent damage and the indestructible ghost can shoot at the boss' weak spot, while you focus on dodging.
My favourite combination in co-op was me playing Ghost and my friend playing the
Gunpowder ship. Its launched barrels have a great damage output, but I found its restricted range too limited for my taste.
I don't claim to be an exceptionally good Jamestown player, but I personally find that using the Gunner ship is easiest on higher difficulties. The ability to change your firing direction is invaluable when dealing with the multitude of enemies coming at you from various angles on the higher difficulty levels. Other ships simply do not offer that sort of versatility.
That being said, I personally cannot get through Croatoa in one piece without using the Bomber, as its ability to deal a lot of damage fast to multiple targets in a straight line fits that level like a glove (You may say that the Charge ship can deal even more damage in a straight line, but it simply can't do it fast enough).