Ship Graveyard Dungeon Ideas

[megamania]

Pirates
Traps with weak boards, rigged rigging
secret doors / trap doors
flooded corridors with rooms that have air pockets within them (course these rooms may have something within them )
swarm of crabs
school (swarm) of dangerous fish
hired muscle.... a wereshark

diving bell
under ground tunnels that lead from ship to ship

glowing coral that has confusion spell-like ability (lights of multi-colors)

and for gigggles.... a Dire Peligan with swallow whole ability (they will eat anything they can)



air pockets that create a "zero or reversed gravity type of environment.

 

[Troll Slayer]

You need some overarching reason for these wrecks to accumulate in one place, or to keep happening in the same place.

Like Orcs gathering up the wreckage to add to their hulk of a floating island/fortress/ship.