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Date: 23 Apr 2018 18:02:41
Title: Chafe — “Aye, there’s the rub. ” *

11:44S 130:09.2W


When running down the Tradewinds, all the pilot books warn you to be on the constant lookout for chafe. Because the gear is set in the same way for weeks on end, the wear is all concentrated on a few key places. If something is rubbing where it shouldn’t you can wear through a rope in a night.


We have been on a steep learning curve and most of the wear and tear happened at the start of our run down the Tradewinds, before we got the hang of it. The cut through halyard, the broken snap shackle and a frayed halyard sheath were all caused by a combination of factors but mainly by me trying to go too fast and setting too much sail. On the plus side we have had almost no damage at all because of poorly set sheets and guys rubbing where they shouldn’t.


image1.jpeg

Frayed halyard sheath


When you are sailing across the wind or upwind, it is easy to tell if you are over-canvassed because the boat heels over. If you are running downwind with the mainsail up and too much sail the boat steers wildly and tries to turn up towards the wind. The advantage of sailing downwind with a foresail (generic term for most of the sails that are usually set on a stay at the front end of the boat) poled out on each side, is that the forces are balanced and the boat almost steers itself. 


And here’s the rub. As the pressure on the sails increases, the usual warning signs aren’t there! The boat increases in speed until you reach its maximum hull speed. Then all that happens is that the pressure on the sails, mast and rigging increases until eventually the boat exceeds its own hull speed and planes, climbing onto its own bow wave and surfing wildly. (You can also reach these speeds by surfing down the face of a big wave, gravity providing the extra force.) Modern racing hulls are designed to do this but a Rustler 36 is very much a heavy displacement hull. 


Caramor is supposed to cut through the water, not plane over it. By the time you generate enough force to allow her hull to plane you have probably broken something. Caramor’s theoretical maximum hull speed is just under 7 knots. On one night Kath registered 9.8 knots!


It’s well known that I am ‘hard of learning’, but we have worked out some guidelines based on hull speed and wind speed for when to reduce or increase sail. This seems to have done the trick and, touch wood, we haven’t broken or chafed anything since.


Post by Franco


*Apologies to William Shakespeare.




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