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StrengthFerrocement boats 75’ long and ¾ inch thick can weather conditions that would destroy fiberglass boats. Impact strength: an example, (averaging 3/4" thickness and 30lb steel content per cu ft), will be approximately 8,000 lb per sq in in 14 days moving to 11,000 in 28 and establishing around 19,000 after 90 days. Only an acceptable thickness of solid steel plate can match it. Fire resistance can stand temperatures of 750 deg C for 48 hrs or more. Mixture and cure timeA perfect concrete cure is between 28 damp days and 28 steam cure hours. The less water, i.e.. dryer the mix, the stronger the concrete. More cement and less sand makes the mix stronger. Cement that is kept damp, so initially sets slower, has no cracking and shrinkage is either at the same rate, or the concrete is already set strong enough to resist cracking by the time shrinkage occurs. Smaller bore wire, i.e. chicken wire, combines better and is less likely to present problems than larger material. Within a boat or larger structure the floors, walls, and deck all become one, having a very strong overall strength. If the compartments are individually sealed the craft is just about unsinkable. Just about any damage is repairable in a Ferrocement boat or tank. Growing largerBox sections, or shapes created out of Ferrocement have the same strength as huge metal beams, they can be pre-stressed so that very tall structures, can withstand wind forces etc. Old wooden boats have for many years been recovered, even when out out shape, bent back, been Ferrocement encased and had many more years of life, most still afloat. Often extra ballast is required after encasing to take the boat back to the same water line as before. A boat made of concrete, steel or wood will sink at the same speed if it has a single form, (i.e. single non airtight compartments) and is holed. Ferrocement craft with many compartments are far stronger than any other craft as the sealed deck forms a part of the box structure and hold tops cannot blow off, as on many other types of ships, if a hold is holed. |
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Copyright New Atlantis.
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