Aquanaut - Episode 3: Exploring the wreck of The Heleopes, cannons on The Low Lee Reef, a close brush with nitrogen narcosis and a prank with a dead fish.

We have a diverse collection of underwater adventure stories in this episode:
To begin, we take our first dive on the wreck of the enormous steamship, Heleopes which sank in 1911.
Why would we find cannonballs and musket shot whilst searching the shipwreck of a coal boat, The Primrose, which sank in 1906? 
The intoxicating effects of nitrogen narcosis endanger the life of one of the team and lastly, to lighten the mood, a prank involving a dead fish.