1) Abounding in rocks 2) Abounding with coral 3) Abundant with shoals 4) Like an atoll 5) Like atolls 6) Like the torres strait 7) Shallow 8) Shelfy 9) Shelvy 10) Shoaly 11) Tricky to navigate 1) Shallow 2) Shelfy 3) Shelvy 4) Shoaly 
• (a.) Full of reefs or rocks.
Reef'y adjective Full of reefs or rocks. 
[adj] - full of submerged reefs or sandbanks or shoals
shelfy adjective full of submerged reefs or sandbanks or shoals; `reefy shallows`; `shoaly waters`