1983 12mR Liberty, designed by Johan Valentjin, at 34 inches


For a change of pace, here we have the design of a scale model, instead of an R/C model. This means we can use different strategies to deal with some issues

Good information on the boat is found on the Wikipedia page, here.

Here are a few, brief, bits of information for context:
Year raced: 1983 June
Designer: Johan Valentijn
Builder: Newport Offshore Ltd.
Length Overall: 19.37 m. – 762.6”
Waterline: 13.70 m. – 539.37”
Beam: 3.70 m. – 145.67”
Draught: 2.67 m. – 105.12”
Displacement: 24.35 t.
Sail Area: 168 sq.m.
Original Owner: Freedom Camp. ?83 SUNY at Ft. Schuyler

The scale model was requested to be 34″. The scale of the model is 1:22.4.


Starting Point – The Original Plan Sheets

Here we have a look at the starting point of the design. These pictures are from the book of America’s Cup yacht design and are missing a lot of detail. I was quite surprised to find such a dearth of information on these wonderful boats.

Fig.1 – Page 1 of 2

Fig.2 – Page 2 of 2


Fiddling with the cockpit design

There are a lot of curves in the cockpit structures of these boats. It was quite a challenge figuring out how to design the internal structure of the cockpit. At first, I considered making many tiny parts that would lock together somehow, keeping the structure as light as possible. Then I realized this is not an R/C model and I can fill the internal structure as much as I want.
  Here we see the first idea for the cockpit, using multiple slots to fit many tiny parts. This just seemed way too complicated.
In this solution, the cockpit is made up of several thin layers, cut in the form of the cockpit. Considering there is no need to make the model light, this solution will ease assembly.
The top layer of plywood and the deck have a slightly different shape from that of the lower layers. This matches what I’ve seen the few pictures I’ve found of this boat.


Ready for Assembly

These frames were cut and I sent them out to the builder before I had a chance to take a picture. Now they are in the builder’s hands and pictures of the build will be added soon. This picture shows the T-rail support and the deck that will be laid after the T-rail is removed.

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