We made ours in the heads from 15mm marine ply, glassed over. Excavation is via a domestic bath outlet, through a Jabsco in line filter to a Par electric pump. It has worked well for 12 years.
A standard shower curtain protects the heads from water and dries very quickly over the boom..
The shower is a garden pressure appliance. Surprisingly, with a hand held 'rose' you get a very good shower from a gallon of water, kettle heated.
In Summer, you can carry the shower out on deck for a clean-up al fresco.
Building your own is relatively simple DIY project, however, as you need some tools and consumables that you may never use again; I would recommend you get a price from at least 3 fibreglassers, not all in the marine industry. Then cost the materials and tools required to the project yourself.
I suspect you will find it cheaper to get it made as this is a small item and you will end up with some material left over; you may never use it, resin has a limited shelf life, off cuts and sheets of fibreglass without resins are worthless laying around.
You could make a saving by building the base or mold though.
But is the right size to learn a bit more about fibreglassing without having to go to a second mortgage.
Avagoodeaster......
<hr width=100% size=1> Old Salt Oz /forums/images/icons/cool.gif Growing old is unavoidable. However, growing up is still optional.