As we added more ballast to my Moomba LSV, the stock swim platform was digging into the wave. Following the path of others, I sourced a sheet of HDPE that was roughly 40"x60"x1" to make a new swim/surf platform. I wanted to replicate the look/design of the newer Moomba swim/surf platforms, but I couldn't find a template or sketch online. So, I went to my local Moomba dealer when they were closed. Somewhere in their archives of surveillance video is a video my daughter sitting on a large piece of cardboard, as I trace the outline from underneath a Craz platform.
I actually needed to reduce the width of the cardboard template by 2" so I took 1" off the edge of each end to keep it proportionate and then cut the cardboard to size. I drove myself nuts trying to get each edge to be a mirror of the other side and finally called it "close-enuf". After sketching out the template on the HDPE, I used a circular-saw to make the longer/straight cuts and then used a jig-saw to round out the edges and make the cut along the edge that meets the stern.
After everything was cut to proportion, i used a quarter-round router bit to smooth the edges over. When I was done cutting/routing, that white HDPE made it snow in August.
To mount it to the existing platform brackets, I countersunk a hole and pushed stainless steel carriage bolts from the top down. I also wanted to raise the level of the platform so I used scrap pieces roughly in the size of the bracket as a spacer. I then bolted the platform to the brackets using nylock nuts before i put the padding on.
For the padding, i sourced a sheet of HydroTurf with the 3M adhesive on the back (their 40"x60" sheet was the constraining factor on the size, my HDPE sheet was bigger.) Rather than cutting a template for this, I just stuck it on the HDPE and then used a sheetrock knife to trim the edges. Yes, you will cut into the HDPE a little bit but you will never notice it since its at the edge of the HydroTurf. If anything, I wish I had taken more care in hand-cutting the edges since there are slight variations (tho I may be the only one that notices). Here's the finished product.
Some people have used 3/4" HDPE and reported a barely noticeable flex. If you're ordering HDPE online, this will save a bit, however the best prices can be found if you source it locally. The shipping is expensive so its worth making several phone calls to "plastics" companies. I found a place that had a piece of 1" in stock and it was a leftover from a job so it was a lot less expensive.
This project was done three years ago and everything has held up well. The edge of the platform takes a lot of abuse (far better than fiberglass) and the HydroTurf with the 3M adhesive has stuck to the HDPE without any edges pulling up. I believe the total cost of materials (HDPE, HydroTurf, and stainless nuts/bolts) was ~$500.