Sea based are hard to take care of. You make one you expand it, you have to gather lots of materials, and and so on. If your going to make one you should make a small one. I know they are essential but if you think about it, you use more materials in them than anything else in the game (unless you want a fleet of Cyclopses for some reason)
Also when they form hull breaches and start flooding. You can fix it with the repair tool, but it gets annoying when you have to make things like bulkheads to stop it. They are cheap, but it adds up overtime. Also, you have to go into dangerous places to make blueprints like jelly shroom caves and bulb zone. (I do not like bonesharks and crabsnakes) maybe you should make a sea base, but consider these problems. Am I the only one who thinks caring for a sea base is a hardscrabble job?
What you do is start small and go bigger as resources become less of an issue and you get blueprints. This will mean that you start with an I-compartment or 2 and a hatch. When you unlock MPRs, you build one or two, being mindful of integrity and building foundations as needed. If you get the water filter, you then build it.
It's not all one big investment. It's many small investments twoard a better base. By the way if you dislike hull integrity you can just use vertical connectors to reach the surface, where hull integrity isn't an issue as pieces not in water don't count to hull integrity and also can not flood (even if the underwater sections are flooded)