Mine has been built by a professional steel boatbuilder
who came out of retirement
to do this one last boat. Is all Corten steel (used to be Austen before Oz shipped steel production offshore) which has been no problem for him to weld. Austenitic steel merits are arguable but only a few dollars extra so why not. I believe there are some merits to the material.
This chap uses stick only, even for light plate. Hull is amazingly fair with very little need for epoxy
clag. Welding impeccable of course. I have seen amateur welding literally fall apart under stress. I seem to remember one famous case of a yacht which had to be completely re-welded in South Africa
- would be unusual case though.
Given that the welding is good, the real issues preventing deterioration are the detailed construction designs which allow shot blasting, good painting and drainage. Has not been a problem for me but could stop you being too intricate.
Some details which would reduce weight simply cannot be done or become self-defeating from a cost viewpoint. No big problem in this boat but might be in a light displacement
A good craftsman can do anything with steel of course but can be labour intensive which is why a professionally built steel yacht is likely to be MORE EXPENSIVE than GRP and its derivatives. Frankly, is difficult to find a true craftsman to do yacht finish in steel. Lots of workboat finish builders around but very few fine tradesmen. IMO.