Okay, picture this; Scuba mask, fins, snorkel and a tank.

Scuba mask: Blank = 0 Stick = 1 Glass = 2 (allows you too see under water as well as on land)

000
121
000

Fins: Blank = 0 Stick = 1 (replaces shoes allows swimming under water, slightly slower than boat)

010
011
011

Tank: Blank = 0 Iron Brick = 1 (allows longer breathing under water)

010
111
111

Snorkel: Blank = 0 Reed = 1 (allows longer breathing, less than tank)

010
010
011

Just ideas.