i dove out of mine for about 10 years, no real mods were necessary. i cut a piece of plywood to fit the cavity between the "bunks" and then cut holes to set tanks upright in the cabin. i also installed 4 tank racks in the cockpit that would hold a tank w/bc. that gave you out of the way storage for 8 tanks and the floor box was for weight belts fins etc. agree with rkc a good swim platform is also needed. i also added a stainless "handicap" hand rail to the transom to pull yourself up and a ladder you can use with fins on. this is the only photo i have hand, but you can see the grab rail on the stern
