Currently there are several decks on most ships, each with spaces we are Going to fill in with a number of ceilings, leaving just a space or two with a ramp down to lower decks.
All of those parts are static instanced meshes, which take up a lot less in the way of resources than other methods but still take up more, the more individual meshes are used.
So why not allow us to build using a Single mesh for all of the decks on a ship?
You could create them from existing meshes in a few minutes - and the end result would be say.. all 6 deck objects and the dozens of ceilings that would usually be put into a galleon, now being a single mesh.
And since the hit on sweep you're using to detect collision for damage already returns Location of the hit, you cant still have multiple regions for damage on the single deck piece to allow multiple remaining Health sections, and by adding material regions you can use some transparencies and similar to show a destroyed part of it without any change to meshes.
..
The same thing applies to player-building of all types.
Walls on top of an existing row should allow 2x wide, 2x high, 2x2 placement as a single mesh, using 2 or 4 pieces from inventory. (faster building and fewer resources)
Basically, anything you already use for LODs could be applied to simplify building by players, improving the building experience For players and reducing the sluggish/choppy play that tends to come with being near large structures or multiple ships.