BACKGROUND
After Booth successfull rebuilt of the M18 I'm thinking about adding a second trapeze, a bigger mainsail and spi to my Marstrom A-cat. I know that Booth didn't win but my interest was focused on the fact that the boat could handle the extra loads without any failures!

Booth used the M18 with 150kg+ of on the wire and used a main beam that had a weight of 50 kg instead of 5kg. The reason for the heavy mainbeam was to reach the minimum weight of 130 kg. Booth used a cut down M20 mast, I will try to use the A-cat mast as it is.

Should I do it?

THE PROJECT

Crew
It will not be designed for "Team beef" but for teams around 130-140 kg, same as Hobie 16.

Sail
The area can be increased from 13.9 to maybe 16.5 m2 by adding more roach area to the main sail. The spi should be around 17 m2.

PROBLEMS
Mast
The top of the mast may be to bendy for the bigger roach and increased loads. The performance to windward in medium winds could suffer from this.
Increased compression of the mast by 30%, reason higher sheet load and another crew on the trapeze.

Main beam
Increased load on the mainbeam by 40%, reason higher sheet load and double trapeze. Booth had 50-60% more load on a WIDER main beam.

Hull
The hull needs to support 220 kg instead of 165 kg which means that the hull will be 4 cm lower in the water. The hull on Booth F18ht supported at least 280 kg and that hull was probably 10 cm lower in the water.

Performance
The boat is narrower than the F16 and 25 kg lighter but the sail area will be lower, 16.5 m2 instead of the F16 18 m2. The lower sail area will be compensated a bit by a 1 meter higher mast and uni rigg instead of main+jib.

/hakan