A Different Take On Rig Tension - Viper 640 International Class Association

Contributed by Rod Beurteaux West Perth, Western Australia.

Rod Beurteaux and crew sailed in the two 2014 Miami EFG regattas and came back for the recent Viper NAs in Long Beach. During those regattas, as crews swapped stories on the dock, Rod indicated that he was sailing (rather successfully) using greater shroud tension than most. When asked the thinking behind that set-up, Rod responded with the following:

Being isolated in Perth was always going to produce a challenge for us to know if we could match speed and pointing with the U.S. sailors. Our breezes are generally heavier, following the U.S. settings just seemed to produce too much mast bend and forestay sag. In addition we found the best way to keep the boat on its feet downhill was to let the boom out to the stay in windy 20-30knot conditions and best way to achieve this was to use high 39-40+ shroud tensions. Long Beach this year was windy but at the lower end of our conditions.

The irony of our results is we appear to have good light-medium air speed. Numbers wise 10 knts+/-2 our uppers are on 30 (pt1guage), the lowers are on 12, and the mast bend is around 50mm (~2 in.). At 18-20 knots we increase the uppers to 36 and the lowers register 14. The prebend at this stage is 60-65 mm (2.5 in.). In 20-25 knots we in have the uppers on 40+ and the lowers are registering 16 and the prebend is 70-80mm (~2.75-3+ in.).

Our mast chock measurement is much less than what is reported in North tuning guide as the heel of our mast is stepped in the middle of the step some 30-40 mm (1-1.5 in.) forward of the North recommendation.

I believe the overall sail depth achieved is similar to the North set-up, we just do it with higher rig tensions and a straighter forestay. Our performances suggest we are close we but with no silver ware in the cupboard we still have a way to go.

Downwind we find it very important to match our sailing angle to the wind strength and sea conditions. In very light airs we try to soak as deep as possible by rotating the spinnaker to weather as far as possible by lengthening the luff, this is done by easing the halyard or shortening the sprit.

When the breeze increases the sailing angle increases as the boat starts to want to plane. In very high breezes 25+ we have found we can start to head back lower as the boat continues to plane whilst soaking down. I have found these general rules are greatly affected by the type of sea conditions and the traffic in which you are sailing.. Assessing your environment on each leg is critical to how high or low you need to sail. Keeping an eye out for the next gust forward of you or running inside to leeward will provide the tactical information for you to head up or gybe.