I have seen references and arguments between hard bottom paints and wearing paints such as copper based ones.
what is considered a hard paint?
"Ablative" paints are designed to 'slough off' due to the movement of the water, exposing new biocides over the life span of the paint. They generally result in a slightly rougher surface and are popular with the non racing crowd. Regularly scrubbing the hull of a boat with ablative paint will remove more paint sooner, perhaps requiring recoating more often too. OTOH ablative paints don't tend to build up layers like hard paints will.
Hard paints don't ablate, they can be sanded and burnished to a very smooth surface and will stand up better to frequent scrubbing.. favoured by the racing crowd for obvious reasons. Paint layers do build up, requiring the periodic (unpleasant) task of removing the old paint back to the barrier coat or gel coat.
what other factors come into play on a steel hull? Im assuming higher maintenance due to risk of rust etc.
Same question for ferrocement, I hadn't seen any decent condition ones for sale with a slip, but I was curious about them.
Metal boats do rust.. that makes upkeep more problematic, and proper maintenance more important (ref my anecdotal tale above - the growth was keeping that poorly maintained boat afloat
) Good metal boats like Amazon, Waterline, etc are priced at a premium like any other high quality build.
Aluminum has it's own corrosion issues and antifouling paints can themselves cause issues.
Ferrocement was the backyard builders material of choice and as a result there are some very questionable boats out there.. poorly finished and executed. I have seen FC boats you couldn't tell from F/g but they are rare indeed. Simply too many question marks for an uniformed buyer.. and an informed one generally knows better and looks beyond the 'great price'.
Your right about one thing.. the only practical route is to find an existing, assumable co-op slip. The problem is they're rare as hens' teeth, and the one that is there is a BIG proposition for a first boat scenario.