Help I'm drowning - Battleship in Lagoon

[Smithers]

I am stuck in the battleship in the Lagoon.

I have used the torpedo to gain access to the inside of the ship.

I can get through the rooms and to the key, but can't get back up to the air pocket in time.

Is there any other way to get the key, or am I meant to be doing something else first?

[Smithers]

I figured it out - after another hour of drowning and Sharks in my groin.

I just had to find the part of the ship with the lock, smash it open [with the rusty hammer] and I got some glorious air.

I have progressed well into the Palawan Volcano and am now climbing up and down the walls of the lava-filled room, trying not to collapse the bamboo rafters.