They were removed due MP sync issues and also because of a chance of rocks spawning right in the docks.

I think if reimplement them as 12-18 underwater tiles (plus their rotated versions) then we can make underwater exploration be more interesting and unique from seed to seed. Besides the exploration from gameplay perspective it can be a great addition for submarines warfare and missions (since these will be a tiles we can put vehicles more nicely, not just in a middle of nowhere in the plain seabed).

Additionally, for world generation we could use different set of tiles for each biome:

• Arctic is very deep with no underwaters tiles spawned close to surface, and tiles are just hills with no caves and archs
• Main is medium deep ocean but with shallow areas, rocks and caves
• Arid is low depth area with many underwaters tiles spawned close to the surface that forms shallow waters with sand islands. Could be also coral rocks and reefs

Tasks are:

• create meshes
• create tiles
• add tiles to world generation
• add tiles to addon editor
• use new tiles in AI path addon (add pathnodes)
• use new tiles for underwater missions as well