Painting the underside of a swim platform?

[dtfeld]

That's strange. Though mine is a bit deeper than yours I would have still assumed they'd provide support struts at 36".

Also interesting, and I haven't yet done a full write up on this, but I'm in the process of replacing/adding struts. It turns out swimplatforms.com sent me too few, and too small, of support struts for my platform. I'm parked in storage behind a very similar boat to mine with exactly the same platform. He has six 1" struts. I was provided with four 7/8" struts. And guess what...I bent the two center struts last year with the weight of my dinghy, which is well below the rated capacity of the platform. I was only in moderately rough water one time last year with the dink on the back. Far from heavy seas.

Soo....yeah...that's kind of why I posted here. I've learned that even if your platform feels wicked, rock solid - she can and will move and flex under load. More than I would have imagined. The good news - swimplatforms.com has been great to work with through this issue. I still recommend them.

If I were going to put a dink or PWC back there, I think I would be re-engineering those support braces and associated hardware. Even 1" tube probably wont cut it. I would have some custom brackets welded up and installed to spread the load across the transom.

This example was from a ski boat. Doubt he was mounting a dink back there, but you get the idea.

 

[GnrlPatton]

My support tubes are 1" diameter 1/8" wall thickness, and I'm planning on mounting 4 of them. My buddy is making the brackets to attach to the transom and then to the underside ribs, and they are pretty beefy.

I'm looking at about 500 pounds of dinghy and davits, and I think between the ribs built into the platform and the additional stanchion support, it should be able to handle that fine. Although those pics that David attached are attractive. I may be able to fab up a vertical support to attach later, like in the top stainless one in the pic.

 

[dtfeld]

Here's an example of the bolts holding the swim platform on my boat. The they failed at the root of the thread, and the nut (with threads attached slid right off the remaining bolt. They didn't fail all the way through.

For an improvement, I flipped the bolts around using a shoulder bolt instead of the full thread and the threaded side is now inside.

 

[GnrlPatton]

Got the install done this weekend, it was pretty straight forward. I allocated Friday - Monday to do the job with my wife and myself and we wrapped it up by end of Sunday. I did have a hand from the yard crew on Friday to lift the old one off and then place the new one on stands in position, everything else we did ourselves. New platform was installed to the transom by end of day Saturday and then I cut/drilled and mounted the new stanchions by end of day Sunday. Monday I replaced the anodes and did a final check before dropping it back in the water by 1pm Monday.

The new platform is awesome, so much more space. I'm glad I took the time to build the stanchions, it had quite a bit of flex prior to getting them installed, and after, no movement at all. I used 1" stainless with 1/8" wall thickness, and the brackets my buddy fabbed up worked perfectly.

Here's a few pics of the install. I highly recommend swimplatforms.com, they had a template for my boat and it fit perfectly with no trimming required.