^^ Done right - you won't need any frame... The glass can be your frame
Then, the only thing you'd have to worry about is how to attach
Here's some tutorials I put together for building an HPV fairing:
large Scale Mold Making
Large Scale Tool Making
Large Scale Part Making
This thing is probably around the same size as what your boat tail would be.... We spent about $2300 for tooling and supplies to make that. We used glass that wouldn't shard when broken (a concern for us - not so much for you) which was pretty expensive compared to the alternatives. The most expensive bit - $500 to $600 of blue foam!!!
But, in theory - you can test out the fairing using the blue foam mold before setting anything in glass
