Is my mainsail really helping?

SFS

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Aug 18, 2015
1,972
West Marine Kayak Tampa Bay
Yeah, it's a little disconcerting the first time you experience it. You wonder if you have a steering system problem or a rudder issue. First time it happened to me, I started looking around for obstacles, and formulating plans C and D. After some thought, I realized what was going on, and we put up a reefed main. Problem solved.
 
Mar 26, 2011
2,935
Corsair F-24 MK I Deale, MD
I've always found the tacking procedures for square rigged boats illustrative. The rig is so large and the boat so long in comparison to the rudder that tacking only happens if the sails are shifted in the correct sequence to insure balance.
 
Apr 9, 2016
35
Catalina 310 South Haven, MI
That's a good trick for helping get the bow around once the tack is initiated. But what I think gaymadhatter is talking about may be related to what several of us have said. For some boats, while flying just a genoa/jib, it is not possible to initiate the tack. You put the helm over, and the boat doesn't want to turn into the wind. It just won't come up, because of the relationship between COE and CLR.
That's it exactly. Thanks everyone for the replies. I think I'm going to have to work on my technique as it appears that fundamentally it should work.
 
Jul 11, 2016
8
Serendipity 43 La Cruz Mex (Seattle reg.)
Recently I've been singlehanding my Catalina 310 alot and I've noticed that in similar wind conditions on a beat or a close reach I can attain the same (or nearly the same) boat speed with just the 150 Genny as I can get using both the genny and the main. Also, the boat seems to point just as well with just the genny and of course there is a lot less heel. I just don't seem to gain anything upwind by using the mainsail. Both sails were new last year. Any thoughts on whats happening?
Probably you're getting enough sail area with a 150 genoa alone, however you can achieve that amount of sail area and your boat will be better balanced and go to windward better with a smaller jib and a full main. If you want to see, try sailing alongside a similar boat with a properly balanced sail plan.
 
Jul 11, 2016
8
Serendipity 43 La Cruz Mex (Seattle reg.)
Sailing for me is also about using the least personal energy to achieve maximum boat speed.
If your objective is simply using the least personal energy, try leaving both sails down and using the motor.
On the other hand, if you have a sailboat because you like to sail, then set a properly balanced sail arrangement with the right sail area for the conditions, so boat is cranked up and feels really great: Small jib, full main, sheeted flat, and romping up wind, feather or reef the main when the breeze is gusty or gets up. It will be really fun and when you get back to the dock you'll know you had a good sail.
 
Jan 7, 2011
2,908
Oday 322 East Chicago, IN
My O'Day 322 will certainly sail with just the jib, and I have done it on occasion. Less often do I sail with just the main. My boat will tack under jib alone (I do have a large headsail...not sure if it is a 140 or what). I can muscle the furler line and roll up the headsail even with no main sail blanketing.

 
Jul 29, 2014
73
Ranger R26 Muskegon, MI
OK, the acronyms are killing me COE, CLR and what was the first one VGR? Someone want to elaborate?
 
Oct 3, 2014
249
Hunter 33.5 & Lake City, MN
OK, the acronyms are killing me COE, CLR and what was the first one VGR? Someone want to elaborate?
Center of Effort - The centerpoint of all forces acting upon the sails
Center of Lateral Resistance - The centerpoint of all forces acting upon the keel and hull
If those two are offset, you either get lee helm or weather helm.

Velocity Made Good - The component of your velocity in the direction of your final destination.
 
Jul 29, 2004
396
Hunter 340 Lake Lanier, GA
COE = Center of Effort. Imagine all the wind load in the sails concentrated into a point, and where is that point fore/aft and vertically above the water
CLR = Center of Lateral Resistance. Imagine all the forces acting on the hull, keel and rudder concentrated into a point. Again, fore/aft and vertically (under water)

Now look at the relationship of COE and CLR. The fore/aft relationship determines whether the boat is balanced under the sail trim and rudder conditions, or if it is heading up or bearing away. The vertical relationship affects leeway and angle of heel (you also have to include COG (center of gravity) and COB (center of buoyancy))
 
Mar 26, 2011
2,935
Corsair F-24 MK I Deale, MD
OK, the acronyms are killing me COE, CLR and what was the first one VGR? Someone want to elaborate?
SOG. Speed over ground
STW. Speed through water
AW. Apparent wind
TW. True wind.

Sometimes folks will mess you up by reusing acronyms:
COG. Course over ground. Lots of folks report their "tacking angle" in terms of AW angle or compass angle, but COG includes leeway and tide.