Material for mast base

Jun 19, 2018
5
MAcGregor 26d Trailer
Hi all - 88 26d here. I have a leaky / slightly damaged / definitely ugly top of my daggerboard tube at the front (right under the mast). I found this pic (below) and wanted to make something similar. Does anyone know what material this might be, something plastic or fiberglass it looks like, would need to be very dense and non-compressable. I think it will help with the gooseneck always scraping the pop top when I'm putting up the mast, as well as give me a nice seal around the top of the DB tube. And it looks very neat. Thanks in advance if you can point me in the right direction.

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