On Collasium! Ari equipped the underwater helm and swam down. Eh? The helm did not seem to work. Okay, perhaps in the dungeon. Heh?? The water on his icon was rising in the dungeon at the same speed as if he hadn't had equipped anything! How come? Does anybody know what happened?
Note: Solo pixie, Athletics 12. Hard - often - hard - deathmatch. Collasium was absolved by using Breath of Air, Restore Health, and the few air pockets in the dungeon. The helm was the one bought in the shipyard - not the one made from shells later even if Ari brought several shells there (no need to buy more helms).

The helm itself is not enough when you visit Collasium, even though there are many air pockets within it, you need to take the shells of the crabs you defeat to the man selling the ship, give him them and he will turn the shells into underwater air tanks so you then use the helm AND the shell which will go where your shield etc would go normally, you may also find artifacts as you go through the game with which you can acquire IRON LUNG which will also help enormously...hope this helps

DOHHH-H-H-H!
When I brought my shells, the shipyard guy started to create helms so that I lost any interest in his doings. Too early. Thanks.
Anyway, I see that Collasium can be done without the helm and the apparatus fairly well. I think I forget about the helm (heavy, lowers parry value by 2) and the apparatus (I bet it brings another disadvantages).