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My information comes from a wide collection of sources. In the 1970's I thought I wanted to build a boat and live on it. Ferrocement sounded very appealing. I read everything I could get on the material and talked to maybe a dozen ferrocement owners. My plan was to design and build a ferro boat.
I eventually participated in 'plastering' one. I, along with probably over a dozen other people spent a very long weekend applying the portland cement to the hull of a roughly 40 foot 'Ingrid' variant. In theory you need to work non-stop until done. In a very long weekend we were only able to finish roughly 2/3 to 3/4 of the boat so that there was a 'cold joint' in the hull. What we ended up with, despite a high level of care was a terribly unfair and uneven hull, thick in places and thin in others. The guy nearly a year fairing the hull and putting a finish on it. 7 or 8 years later I saw the nearly completed boat and there were sections where we must have been thin because there was a telltale pattern of rust.
Also in the 1970's, I also worked in a boat yard in Florida where we hauled a Ferro cement boat for an insurance survey and when we did, the layer of cement that was over the reinforcing peeled away in the area of the boat where the travel lift straps were bearing. The surveyor who was supposed to be an expert in Ferrocement tapped the boat out and said it was other fine but when I was working with the owner to make the repairs, we were able to peel away large areas of the skin to reveal a lack of bonding at the reinforcing and rusting reinforcing material.
Some of my comments come from discussions with yacht designers. When I worked as a yacht designer this was a popular topic in the office. Some of my comments come from discussing ferro boats with marine surveyors. Some of my comments on the properties of ferrocement are based on my knowledge of concrete that I obtained during my masters degree in architectural structures and during my career as an architect. Some of my comments are based on conversations with past and present ferrocement boat owners over the past 30 years. Some of my opinion comes are simply based on basic yacht design theory. Some comments are based on conversations with brokers, some of whom will not even take a Ferro listing. And, yes, some of my opinion comes from books and from 'generally held opinion', which, right or wrong, none the less affects the resale price of a ferrocement boat.
I know that there are ferrocement boat owners who love thier boats but to paraphrase Lincoln,"I have never met a man who had an ugly wife, a dumb kid, a bad boat." In my life, talking to thousands of boat owners over the years, I have consistently been amazed at the glowing reports that I have heard from owners and crew who own boats that by any fair and objective standard are really poorly designed and built.
In the end I stand by my conclusion. I know that there are well designed and constructed ferrocement boats out there. I know that there are owners for whom the compromises in sailing ability, greater maintenance, reduced stability, limited resale value, low strength to weight, and carrying capacity for a given size, etc, really are not significant, but for most of us, at least here in North America, the risks and realities of ferrocement, especially when there are so many better choices out there, really are not worth it.
Respectfully,
Jeff
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