I believe that you need to think carefully about embarking on a ferro boat of any description.
We were involved in the marine trade in Austraia during the "Ferro boom" of the 70''s, and during this time - it tended to be the material of choice for "low budget" DIY boatbuilders, because the material was very cost effective in terms of producing hulls.
HOWEVER - we always felt that it was a false ecconony due to the fact that while the hull may have been cheap to build for a DIY builder (where labour is not costed in) the fitout and installation of equipment cost the same regardless of the shell material.
Typically, there was absolutely no quality control, relying on the expertise of the owner builder & perhaps the contract tradesmen used to cement the mesh. The building process was very sensitive to mesh layups, concrete quality and curing time and procedure.
The single greatest problem with ferro is that that it has very little impact resistance. And there are many ferro boats in Australia that are now "artifical reefs" due to this factor. We have a bar crossing in our local area where the bottom is home to a number of ferro yachts & fishing trawlers that went aground & broke up.
There was also a notable ferro yacht that won a Sydney to Hobart yacht race (Helsal) - she was a 60'' Joe Adams design. She now lies on the bottom of Singapore harbour - having gone aground on a delivery trip.
We also have a friend who bought a ferro yacht - 70'' that had a stainless steel mesh layup - the boat is currently on the slip & has numerous "holes" where the ferro has "delaminated" in chunks & seawater has migrated throughout a considerable area around these holes. I guess they are grinding it all out & re-filling with an expoxy mixture. But what a pain !!
The reason for the cheap price is due to the fact that the material is ferro & basically has no resale value - despite the equipment level.
There are some excellent examples of ferro boats out there, however, as a cruising vessel of choice I personally would probably be looking to another hull material, given that sometimes s.... just happens beyond your control, and I would rather be in a hull that had a little resilliance.
For your info - Hartley (a New Zealand Naval Architect) and a number of other designers in the Southern Hemisphere designed yachts specifically for ferro. In our area - he has an extremely good reputation for the design of good cruising yachts of all materials, and there are many examples of his designs around the waterways. He markets his designs in a similar manner as Bruce Roberts - ie targeted at the DIY builder.
To my knowledge - I don''t know that ferro as a material has been used in Australia now for a number of years. It is also fair to say that in the 70''s there were some commercial builders who specialised in ferro - but they have all now gone by the wayside.
Maybe if you have a specific budget - look to something smaller in another material - because like many of us - this probably won''t be your last boat & I am sure that you will have to "give" the boat away to dispose of it when you want to change it out.
If you want to continue on with the boat, in answer to your original questions :
1. Check to see whether the boat was DIY or built by a commercial establishment & in Sth Africa - like Aus there were a number of reputable ferro boat builders.
2. Continuing hull maintenance will be a product of the external finish - our friends have just sandblasted down to the finishing grout & have re-epoxied the hull & finished with a 2 pack paint. So, it is much like an older fibreglass hull or steel hull. Gouges & nicks are treated with an expoxy fill - sanded back & painted.
3. The hulls were intrisically strong - but as pointed out above - have very little impact resistance.
The selection of hull material is finally up to you & obviously your budget. All materials can be safe given good manufacturing procedure and good seamanship - but perhaps ferro is not as forgiving as other materials in terms of being able to withstand accidental grounding or impact.
Anyway - good luck - hope this helps your decision, and my sincere apolgies to those of you who have and sail ferro boats.