My Swim Platform repair project.

[jrbrein]

Much has been written about swim platform repairs but in my repair project, I found a bit of over engineering in the transom

While hauled out to repair my trim tabs, I found the old bronze swim platform brackets had cracks right at the 90 degree welded joints. See the black circles.


I decided to remove all 5 of them and replace with 316 stainless brackets. I had the fabricating shop make them using 1/4’ thick by 2’ wide flat bar and 1 3/8” tubes welded on.


I found that there is 1/2” bronze plating glassed in to the transom in the areas where the bracket bolts were located. Most of the original bronze bolts were frozen in place as well as an odd assortment of stainless fasteners holding the brackets. It was a real mess. I cut the heads off and removed the brackets. I grinded the stumps of the old fasteners down flush with the bronze plating.





Jon

 

[jrbrein]

Some dissecting and hole drilling to establish the boundaries of the bronze plates. I then repaired all the fiberglass with biaxial glass and West epoxy and faired everything before covering the repaired areas with Interprotect 2000 then bottom paint.



I used 3/8” silicon bronze fasteners which I drilled and then tapped all new holes in the bronze plating installing 5 bolts per bracket on the transom side of the brackets and 5200 caulk to seal them in. I did not thru bolt anything since the bolts were screwed into 1/2” bronze.

Jon

 

[jrbrein]

As for the swim platform, I made some minor repairs, checked for moisture (there was some but not much) and then painted both sides with Oyster White Awlgrip.


I fastened the swim platform onto the brackets using 5/16” 316 stainless carriage bolts, 4 for each bracket.

View attachment 44032View attachment 44033


Jon

 

[racclarkson@gmail.com]

That looks like a nice job. I have a special interest; my platform was torn off in a storm a couple of years back. I salvaged the platform, and the popular consensus is that I should put it back on. My brackets failed at the welds. They were also thru bolted using three 5/16” bolts per. So the embedded backing plates are news to me. I saved a bracket for a pattern, but wouldn’t be upset if you posted the full dimensions of your brackets. Very helpful post. Thanks.

 

[jrbrein]

Thanks Robert.

I had the fabricating shop duplicate the original brackets since the brackets were 3 different sizes. By that I mean due to the V shaped transom, the center bracket had the longest transom leg and the 2 outer brackets had shorter transom legs. Of the 5 brackets, there are 3 different sizes. The photo below should demonstrate this.

View attachment 44048

The picture shows the different sizes of the new brackets installed. Also, The transom is not flat on my boat but curved. The original bronze brackets were bent at the 90 degree angle to make the swim platform legs straight fore and aft and parallel with each other. I believe that this created a further weakness at the 90 degree welded joint. That is where the cracks developed.

Feel free to contact me at 757-635-2119 if you wish to discuss this. I am afraid I do not have measurements of the brackets for you.

Jon

 

[racclarkson@gmail.com]

Thanks. My brackets were all the same size based on bolt spacing. I need to take a new look at my platform. Thanks for the info.