I made it using a spline cage and using the surface modifier. After having surfaced it and using 100 steps (maximum amount of polys), I get 663065 polygons when converting it to an editable poly. Since my computer kind of starts to lag now, I reckon this is way too much. Keep in mind that this is only half the ship, which I'm going to mirror later. When I reduce the amount of steps of the surface modifier to 30 (seemingly doesn't affect the appearance at all when compared to 100 steps), I only get 62465 polygons. In fact, the model doesn't look much worse than 30 steps until I'm below 20, though some edges are slightly more blurry at 20 compared to 30, however these 10 steps decrease the poly count by about 20000.
I've googled this and found nothing, so what's a reasonable value to aim for? This is a pretty large model, about 30 meters in length, 3 meters in height (without the sail) and 6 meters in width. There'll probably be a bunch of these next to each other in the mod.
Thanks!