Hosts: Alan Sprague and Mike Joyce
Topic: “Raw Faith”, cement boats
What about cement boats? Ever heard of a cattail boat? Is it fun to sail in the fog with a lot of barges around?
Guest: Captain Giffy Full
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One thought on “Boat Talk 06/13/06”
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Thanks for the opinions expressed on ferro cement. Boats without rebar have proven better:
One ferro-cement innovator Martin Irons improved ferrocement durability, (http://www.ferrocement-consultant.com/ of California). Martin developed laminated-wire-mesh as primary reinforcement. (To replace unnecessary steel bars in ferrocement). It was apparently proven in a “40 knot patrol boat hull”, tested for the US Navy. Marine Technology (SNAME), July 1984, pp. 277-296.
I’m interested in simplifying reinforcement further. Use of overlapping rings to build upon fundamental principles of predominantly fine gauge wires as primary reinforcement. Perhaps even rather than coated steel wire I’ll bet the newly distributed high strength plastic might replace metal use all together. However, at present it is only sold chopped up into fibers. (PVA plastic is poly vinyl alcohol). As far as differential expansion of normal materials is concerned, the rings reduce the differential length over-which steel and cement would need to differ. Whereas rebar needs to be much longer. With a decent shop set up, my bet is that ring reinforcement would be competitive.
One cement manufacturer is promising an ultimate pre mixed cement which claims to need no-other reinforcement wires or bars at all. It is said to have ductile properties similar but less than mild steel. Ductal: http://www.ductal-lafarge.com/ . However, it seems unavailable and would require complicating curing methods. In any case, one of the ingredients might be PVA.
Great show, just wanted to contribute a few thoughts and can’t always tune in live. I enjoyed your talk of ferrocement on line. ~Bo