Haven't built anything for a while due to lack of space (too many models) but the urge to build something was too great. After looking at many options, I decided to go with something 'easy' to build. I found some full size plans for an Australian MkI Moth which I'm building to a MKII (double chine) style.

I'm building in foam and glass again to make things easier. It's 850mm long and 310 wide which is roughly 1/4 scale (original is 11 ft)

Started by converting all the lofting measurements on the redrawn 1953 plan to metric and dividing them by 4 to get the scale.
Next was creating the ply deck, then contact gluing onto it a piece of dense 50mm building polystyrene. This was then shaped with a surform file and the chines shaped afterwards using eyeometry. Then the 10mm deck foam was glued on so the deck sheer could be shaped.

Next the cockpit foam was routered out, and basswood sides and inner transom piece epoxied in. After that, the ply outer transom piece and hardwood nose block was epoxied on.

The centerboard case upper and lower ply braces were routered out (using the mill and a 1/2" slotting bit) large enough to accept the case sides, leaving enough room for the 6mm aluminium keel (can't use a centerboard for obvious reasons) which will have to have a bulb fitted.

A rebate in the bottom of the hull was routered out for the lower c/board brace. These braces are needed to form part of a box structure with the floor and cockpit sides which the c/board can lever on. Once everything is eventually glassed in, it will make it very strong unit, so the foam will just be the shape surrounding the box, and not having any strain put on it. The ply deck will take the strain of the stays/mast.

The cockpit floor was cut, and will be slotted the same as the braces, then the c/board case will be built.

The mast on this is 1.486m tall, - sail is -luff -11.295, foot 609mm, so quite large for a small boat. The full sized boat is a lot of fun to sail, so this model will be interesting to sail. Unfortunately, without the human input required, and being a performance boat, it may assume the attributes of a submarine in a stiff breeze, - time and testing will tell.

The basic mast was made from 12mm ally tube, boom from 10mm. Sail pattern was cut from art card to the plan. All laid out on the floor to get an idea of what it will look like.

PDF is the history of the Moth. There were a number of versions round the world as it went along,- scow, international moth (dinghy type) and todays high speed foiling moth.

Lots more to do yet

JB

2025 world champs, off the Whangaparaoa peninsula, just up from where I live.

https://australianclassicdinghynetwork.org/moth

https://www.moth.asn.au/