I'm going to start a new thread and not hijack the existing swim platform thread.
When I was looking for a inexpensive option to replace my swim step I didn't find much info. I found some people have used mahogany so I went for it.
Used maybe $70 worth of mahogany from the hardware store, waterproof wood glue, stainless screws, and teak covered Cetol. Might have $120 into the entire project. I have had it on the boat 2 seasons and looks great. Mounted platform to factory brackets.
If I was to do it again I would used a darker stain, match curve of step to the curve of the transom, and mix some silca sand in with the first coat for Cetol. Right now the step is very slippery.