For the type of boat I'm building I feel a good swim platform to be essential for getting on and off the boat while at a harbor or at anchor. I want a swim platform that will be able to take serious amounts of abuse and be basically bullet proof while being an easy to navigate tool of function. I decided upon building the swim platform out of stainless steel given my opinion that it will receive its fair share of dings. A wood platform, while attractive, I felt would one more maintenance and repair item for me a little further down the road.
Once I decided upon an elevation above the water line for the platform I began by taking my ripped sections of 4" sch. 40 and adding back in a notched section that would make up the longitudinal frame of the platform. After these were welded to the hull perfectly level with the drawn water line I began the task of bending the athwart ship section of the platform. The only part of the stern that could handle the force of bending the pipe ( I was using the stern as my pattern) is the area where the cockpit deck meets the transom. I welded some jigs on the starboard side of the hull to hold the pipe fast and on the port side I welded some cleats to use as pull points. Using a one ton chain hoist I bent the 4" pipe unit she would bend no more... pretty much the shape of the transom less a little spring back on the pipe. Since I'm not building a watch and only the most of anal observers would realize the shape of my bend was not an exact duplicate, I called the job a success. To make the transition from the longitudinal pipe to the athwart ship section, I used two 90's cut to the fairest line I could make work. I know I'll need a little fairing compound on this area, but all in all it looks pretty damn good. I added 3/16 x 2" frames to support the platforms 12 gauge deck.
The platform extends 24" away from the transom and while I'd prefer 30" I'm satisfied with this depth. This is now my only way on and off of the boat while I build her. After a few trips on to the boat with the new swim platform I soon realized that a better set up steps other than conventional boat ladders were in order, so I designed what I consider to be a good alternative. I welded the treads for the steps out of 3/16 stainless and used some left over 4" stainless pipe with some 45 degree fittings for the stringer. The odd shape of the tread was my way of marrying the winding of the path of the steps with the 4" pipe that supports the steps. Given the fact that the platform is some 10 above my concrete floor I added some "U" shaped safety rails fabricated from 1.5" sch. 40 stainless along with a safety rail to help one navigate the steps. All the vertical pipes were fitted to the 4" section by clamping them in my mill and using a 4" hole saw to cut the profile for an exact fit to the 4". A boarding ladder will pin to the port side safety rail and on the outboard side of the rail. I added a bit under the middle safety rail and while I now think the proportion of the bit is a little off, I have yet to decide if I should make it shorter ( the bit is 2" sch. 40 with a solid bar of 1" welded through). Besides keeping me safe from falling and smacking the concrete I really feel the rails and the steps will make boarding the boat very safe and easy for even the drunkest of guests.