i was testing the mod and noticed a few things.
The Cargo ship have a stupid large inventory and in comparison the Tank Ship have a small inventory.
Ships are very cheap

Suggestions and tips:
- Make some Tiers of Ships and Platforms, 3 at least, (just change the HUE/color for the sprites)
Cargo Ship inventory size = 250 / 375 / 500
Tank Ship inventory size = 150k / 225k / 300k
-Some pipes and Storage Tanks that can be placed on water would be nice.
-A small but fast boat also would be nice
-Compatibility with bobs (changing the recipes to use his resources)
-A new Tab with all things of the mod.

You can take a look at my mod HeavyTank to see how i made it the Tab thing.
About the Crane... i was thinking a while ago to make a big inserter mod, a slow but with a high stack giant inserter (2x2 size), maybe its time to try make it real...

Also, Great mod.
If you need some help, just ask.
Im probably going to make a few changes for personal use and maybe, with your permission, a "expansion" for your mod.

thanks for your feedback. I am personally not a fan of having different tiers of everything. but you're very welcome to create an expansion yourself and publish it. The small and fast boat is something i have been planning on adding to the mod.