Thursday, July 11, 2013

Karo, rigg evolution

After returning from the footy goldcup i was super inspired, went straight to work, improving the Karo.
(I will write my report on the race as soon as i can catch my father for the photos)

In france i realized that the next step in my footy development will be a new type of rigg.
My unariggs had some drawbacks, which became visible on the race course, sailing against other boats and in "crowdy" conditions.

The first was that my higher aspect ratios did not carry as much sail as competitors with two sails, they produce the same speed, but don't accelerate the boat as quickly as a classic rigg does.
The centre of effort is higher, so the single high sail provides quite a lot of heel.

The second thing was they were to stiff, sort of hammering the boat when not under power, and loosing speed through tacks, so a softer material has to be found

The third thing was the damn backstay, i got caught numerous times while sailing at the front of the fleet or at start.

On the way back I went through the sketches i had made for the classic rigg.

Today the rigg was finished, it has funny geometry, sporting a Stollery mainsail, and a 450cm2 jib, with a combined area of 1400cm2.

The mainsail is made of icarex, kite material. For now the jib is kimoto foil(it is to stiff)
The main thing is no backstay, i am sure that the chance of getting tangeld with the shrouds is way smaller, on this rigg they provide forestay tension.

The main benefit is probably lowering the CE for 12cm.  
The jib was provisorically attached, so i could take the boat for a spin, a removable swivel will be introduced so jibs can be raplaced easily.
Todays impression was superb, i managed to put the overall CE about 2cm further behind than with the unarigg. The boat sails way more responsively than before, and nosediving seems to be reduced.
For the first try the performance is very satisfying.
Tomorrow i plan on taking both Karos to the pond, and hopefully finding someone to sail one of them for comparison.
Clips follow.


The plans for this rigg:
1. Make a 1800cm2 version
2. Make a 1000cm2 version
3. Compare on water performance to the unariggs
4. try:  moving mast aft & changing sailarea ratios(bigger % jib),  getting lift from the jib


I will put down my thoughts about the new hull design in another post.



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