Welcome to APUG Pedro.
A few years back our local arts school featured a chap who used a home made under water pinhole camera to take some great shots off the coast of B.C
His work was done from a kayak and what made it really unique was that he developed his film On Board. You got it.Had a mini processing unit built into the deck of his kayak. Fascinating stuff!
I will call the gallery today and get his name.