The Ritchie Unit System dates from WW1, altough it was extensively used in WW2. This is his book, maybe you can also find it in a library (ask for an interlibrary loan if necessary). A New Way of Building Concrete Ships. The Ritchie Unit System. A Short Account Illustrating the Old Method and the New of Building Concrete Ships. by Ritchie & Black.: Very Good | ROBIN SUMMERS BOOKS LTD https://www.abebooks.com/first-edition/New-Way-Building-Concrete-Ships-Ritchie/31956055903/bd
A little bit more complicated then that. The individual panels are joined via a pin and wedge connection to form the hull shell. The panels are about 50mm thick and span one or two frame bays, depending on the size of the ship. Then a complete system of longitudinal and diagonal stringers is cast in place on the inside, forming something resembling a modern isogrid. The plates have protruding anchors to tie the rebar for the stringers to the plates. Ritchie also invented a steel spring clip to be used instead of tie wire for rebar in order to reduce assembly time.
It's not neceserally about the size but about the equipment. Amateurs don't usually own vibrating tables and cranes to be able to make even flat panels. This was a method geared primarily towards mass production. It is however possible to adapt it to amateur construction using a minimum of special panels, with bolting and epoxy for assembly, even for relatively small boats, cementing the panels by hand. In fact that's what a team of students (TU Dresden 2011) did once for the open class of a concrete canoe race, making an open boat, 11.8mx1.8mx0.65m, 2.8t, from 0.525m long identical segments (full transverse pieces) plus stem and stern sections. The segments were done in a closed mold using self compacting concrete and came out at 135kg. There were two segments with bulkheads at the end, each 230kg, serving as anchor points for the post stressing rods that hold everything together, plus the stem and stern pieces, done with textile reinforcement instead of steel. The whole boat was done using two molds, one for the standard sections and one for the stem section, wich was then modified to build the stern (they inserted a bulkhead to form the transom).
Not at all. The material properties are completely different, including density. Easy to think does not mean it has any connection to reality.
We don't know until we try.
We know because we have put the time and effort into learning. On the other hand, you have the square wheel syndrome. Every expert is a fool because your square wheel is different, therefore better. Instead of being arrogant and making wild claims, show an example that proves me wrong. That would be interesting and I would welcome the lesson.
Collin Archer boats are very heavy, so not typical at all for modern boats. Maybe compared them to a Frers or Ron Holland to be more in line with current expectations.
