Thursday, May 15, 2014

new F5g b-rigg

Above is the new b-rigg to be used with wide F5g class boats, it has 3900cm2 of sail, the man/jib ratio is 60/40.
This is the second generation of b rigg, the jib is borrowed from mk1 b rigg. On later riggs the boom will be replaced with a telescopic one.
The main has a shorter foot(5cm), and is 5 cm higher. The area is the same as mk1.
The shorter foot brings the force resultant closer to the centerline. Meaning that the main doesn't put so much strain on the rudder when running.(better directional stability) The shorter sail also makes the boat more agile(force resultants of main and jib are closer together), making it easier to bareaway, and sail the boat downwind with the waves.
The mainsail is higher, to keep the heel angle and speed up throught the luls.
The 3d printed kicker and the stainless spreader make setting the rigg up easier.
Mast bend, when Fila si supported at hull and held horizontally by the tip of the mast(biggest possible moment) is about 4mm   ~ 0   :)
I am very happy with that.
the basic mast curve, depending on the conditions it can be trimmed
Yesterday was the first day of testing.
The winds here in north-east Slovenia are fourious, yesterday the average was 17 knot on the airport(500mm away from the industrial lake sailed), gusting to 25knots
the conditions were abit to fierce for b rigg, sadly the c-rigg is still a work in progress
i bent the mast real good, trimming the sails for speed with a really lose luff
upwind is ok,tacking good, speed is ok, angle not so much
Downwind is a blast
Gusts above 20knts were unresistable, submarining was unavoidable
overall i am happy with the rigg, however i know i have to get more days sailing it
the only really disturbing thing was the main boom dragging through water..
2.nd day of testing.
For this day the forecast was 30+knots with gusts up to 40 knots..     ..this is not very likely, because if a 40 knot gust was to hit the city park, half of the old trees would go down..     ..none of the trees in the park went down and the day is past..
..anyway the wind was to strong to go to the industrial lake, the pond in the city park seemed a good alternative.
The foot of the mainsail was cut and the boom was raised for about 4cm = problem solved
conditions were gusty, there was almost no wave, i could trimm the rigg to deafult settings 
speed dropped compared to the day before, but lots of angle was gained, tacking is spotless
downwind is good, catching the boat going into irons is much easier now
Today the mast prooved to be abit to stiff, it doesn't want to bend in a gust, this is desired to loosen the luff and gain the all important speed.
I have to try with less pre-bend in the mast when the rigg is set.
I recon 10 more hours of sailing with the b rigg in b rigg conditions to sort out the little things are needed.
After that the boat is competition ready.

The little things:
-Mast pre-bend
-Match the luff curves perfectlly
-find ideal main foot depth
-fix spreader and wang rings with super glue

Some clips of todays sailing:

Fila is beating upwind, the speed is good(note the flowers and branches) although it is hard to judge as i am walking with the boat.
In the strong gusts leeway increases and speed is lost..    ..this is predicted, and can not be tammed, yet.
Downwind, the main luff is too loose. I have walk quickly or lightly run in order to keep up with the boat.
The bow is pressed into the water. That is horrible for speed as we know. In the future inverse foiled rudders and forward foils should take care of that.
But for now i am confident that if such conditions appear on the race course Fila will be in the foreground if not even dominant.

Here you can see that the strong gusts are barelly survived. It is also obvious that i have to sheet out after a tack to gain speed. Lighter sails should reduce the speed loss after tacks.
Downwind...      ...ehh, ..    
In such conditions i would always choose the b rigg, to the C, just to get through the luls.

C-rigg comming soon.
That's it for now.

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