An added thought about steel

[Rick]

Mild steel is cheap and ubiquitous. Carry it for emergency repairs. It is stronger, in general, than either stainless or bronze and easier to cut, file and drill. If you fabricate a repair out of aluminum or steel you can often protect it with a good protectant spray which will last until you cross the Pacific or Indian oceans before rusting into a state of structural concern. Even steel pillow-block bearings can be mounted outboard of the vessel with protectant on it and survive sufficiently long to let you get "there".

I agree completely. I coat my stock with parafin wax so it will not rust up too bad until I need it. Steel is much better to work than aluminum (does not clog files and saws), is strong enough for most things, and bends well for fabrication work.