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‘Experiment’ Cat Lessons from the weekend…

This is an ‘old’ image but sort of highlights a couple of the things we are ‘experimenting’ with on the Viper now…

One, mast tune and rake
Tw0, daggerboards

During the Cat Nationals, we reset the spreader angle and tightened the diamond wires. That seemed to give us a lot of pointing ability but we were looking for more speed!

Two weeks later it was into the Acclaim Monsoon Cup, there we loosened the diamond wire tension to try to ‘find’ a little more speed. That also seemed to work too but we never really got to measure it shoulder to shoulder with the Nacra 20’s.

This weekend… we’re still looking for more speed! But that is the life and times of a race boat!
So what we did, was to rake the mast back more than ‘normal’ the results from what we felt were much better up and down wind.

UPWIND. The boat accelerates much smoother.
We had a good benchmark boat with us (Viper Isdoo!) who had made a better start. Wind at this stage was light a variable, no trapezing. In these light airs the increased rake seemed to generate more speed – which was a little bit of a surprise! But we also noticed that Isdoo! had the mainsheet too tight for the prevailing conditions so the head of the mainsail was standing to windward with no flow.

As the wind increased (one on trapeze), the ‘more rake’ Viper pointed high, accelerated better and appeared to maintain a higher average speed and so it seems to be heading in the right direction.

The real reason for increasing the mast rake was to try to remove some of the lee-helm that we seem to have when running with the kite up. Increasing the mast rake will move the centre of effort aft… we’ve still got lee helm but not dramatic so we think we can run a little more mast rake.¬†Definitely, the boat was quicker downwind (single trapezing, kite up condition) as the bow lifted with greater ease helping the Viper onto the ‘plane’ earlier.

So the boat was easier to drive upwind and downwind!

Our next ‘test’ will be to increase the mast rake until we hit the ‘pothole’!

For those who raced over the weekend… after rounding Frontier buoy, you will have noticed that the tide was running out perpendicular to the line of travel i.e. lifting. The water was also perfectly flat and enough pressure to hold 1 occasionally 2 on the wire.

We progressed upwind and bit by bit, pulled the daggerboards up.
Measuring from the bottom of the ‘vee’ in the handle (see picture above)…
– we started the leg with about 20cms showing, the boat felt good and speed/angle was still spot on.
– then we tried 30cms showing, also good but with a little more weather helm coming creeping into the feel
– with 40 cms showing, more weather helm on the rudder and the boat was now lacking ‘bite’ and a little squirrely!

But remember, this is in medium air and maybe 40cms showing would be good in heavy air – yet to be tested!

Ahh more ‘experiments’… stay tuned!

About prosailing

In Southeast Asia a long time and all the while, sailing cats. But the cat love-affair began when I finished building my first catamaran at age 15... "never again". After building 2 more Formula 16 cats in Malaysia it's really 'never again'. Now we have a large fleet of high-tech speed machines including the Nacra 20 Carbon. Then we decided to spread our wings a little more and imported the Corsair Dash 750. Now we are well on the way to establishing a Coastal One Design Dash Class. As a test bed, we had 4 Dashes take part in the Neptune Regatta and now the plans are rolling out.


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