Now that would be interesting. Imagine if large boats were limited by the underwater geography and couldn't go up 1-tile canals and rivers.
Although the question is how would you see underneath the surface with current water graphics? Translucent water tiles?
I'm not sure if limiting ships using sea depth is a good idea, there is already possibility to limit speed and therefore make rosters for open sea, for rivers/canals or universal ones.
But having some tiles deep would give opportunity to:
[*]build underwater tunnels if sea bed is not below 1
[*]limiting building bridges if sea is deeper than given setting (there is already such setting for terrain).
My experimental openTTD server: 18.104.22.168:3979 non-standard client, now testing: JGRPP http://tiny.pl/ggnch
Projects: Reproducible Map Generation patch
, NewGRFs: Manpower industries, PolTrams, Polroad, 600mm narrow gauge, preindustrial houses, wired, ECS industry extension, V4 CEE train set
Addicted to freeciv longturn.