Thread: Steadying sails
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Old 08-17-2017, 12:16 AM   #7
cardude01
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City: Victoria TX
Vessel Name: Bijou
Vessel Model: 2008 Island Packet PY/SP
Join Date: Nov 2012
Posts: 5,290
Quote:
Originally Posted by dhays View Post
Cardude,

You likely have already considered this but....

There are two wind speed to consider, true wind, and apparent wind.

If you are motoring at 6 knots with no wind present at all, you will be creating your own 6 knot headwind. In this situation, even thought you are heading directly into the apparent wind, you can set the main so that it will fill, give you a tiny bit of increased speed (maybe a 1/8 to 1/4 of a knot) but significantly reduce your role.

If the true wind is coming from dead astern at 6 knots, and you are motoring at 6 knots, there is no apparent wind. In this situation the sails will be completely ineffective.

So, unless you have a tailwind of sufficient speed to overcome your own speed (such as 15 knots), downwind will not be as helpful.

A lot of this will improve as you gain familiarity with sail trim. Trim the sails based on the wind they are actually experiencing.

I think that's exactly what I was experiencing. Motoring basically downwind at 7-9 knots with true wind varying from 8-15. So that's why I was getting the cyclical luffing--basically no or very little apparent wind at times. Should have been easy to figure out in retrospect, but I just don't have the experience yet.
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