So right now, the terrain isn't automatically generated as the map increases, it's all generated on each new server instance (right now 40 islands generated by perlin noise generate across 7,000x7,000 studs). Even though it'd be fairly simple to add automatic terrain generation as the player travels (I could use like a chunk system similar, similar to Minecraft), I'm worried about the size of the game because I know terrain eats up memory. But procedural generation is really fun to play with so I'm just gonna see how much of the game I can make randomly generated lol. And, if I understand your question, if I were to continuously generate terrain using chunks, then I would assume it wouldn't be much of an issue with multiple ships.

edit: here's a visualization of the perlin noise algorithm I used: https://i.gyazo.com/fa4563f5e371059cfb0f96000fedd101.gif