I am having a crisis of confidence. I have recently been crewing on a J-30 as the mainsail trimmer and the skipper has me trimming the main differently that what I do on my San Juan 21. The crisis centers around the two rules involving the top batten being parallel to the boom and the top tell tale flying or not. On my SJ 21, I don’t worry much about the batten being parallel and maintain the top tell tale either streaming aft in winds over 10 and popping out 50% or so in winds under that. This will make the top of the sail twist a lot in light winds. On the j-30, the skipper wants the top batten parallel dispite the fact the top tell tale is back winded constantly. Another skipper on a Catalina 320 also insisted on this. So, what is the best way of setting the main???
Main Sail Trim Question
- Thread starter Stephen Jensen
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Book Learning !!!!
Presumably you are meaning when hard on the wind. I think your skippers have been reading books on how to set sails written by 'experts'. Clearly the tell tale just breaking indicates the top of the sail is correctly set. Of course the other tell tales should be doing likewise. Sometimes you can feel a bit more power with the head of the sail stalled but I think it is an illusion and not as fast. I also use mid chord tell tales to really see what is going on. My two cents worth
Presumably you are meaning when hard on the wind. I think your skippers have been reading books on how to set sails written by 'experts'. Clearly the tell tale just breaking indicates the top of the sail is correctly set. Of course the other tell tales should be doing likewise. Sometimes you can feel a bit more power with the head of the sail stalled but I think it is an illusion and not as fast. I also use mid chord tell tales to really see what is going on. My two cents worth
On our boat there is one overiding rule: if the boat goes faster, the adjustment works. Having said that, the top batten should be kept as near as parallel with the boom as possible. If this is causing the top teltale to stall most of the time and the other teltales are all streaming, then there isn't enough twist at the top of the sail. Easing the mainsheet very slowly should begin to allow the top teltale to flick in and out. At the 50% point, the twist is set(excuse the expression: nothing is ever really 'set') The traveler will need to move up to keep the rest of the sail happy. What your skippers are thinking about is almost always boat speed. Usually, a more powerful(flatter) main is faster. If adding the twist increases boat speed....well you get the picture.
get the handheld gps out ...
and see if you can tell which works faster. The J30 is very light and depending on wave conditions and sail conditions you will have to find optimums. I am surprised that you would race without the gps to guide you on trim. half the time in 15+ wind conditions the guys around here seem to have the main detuned, because "YOU always sail overpowered in a J30" and it is pretty easy to get to hull speed. I'm betting that you may not see much difference. Of course the key is the helsman's ability to keep the boat maxed out to the wind shifts and wave conditions instead of dicking around with how you have the top batten set ... Maybe on a flat lake with absolute steady wind direction and no current this trim might make a noticeable difference. On a nice windy day in a Jay five 225lb ers ... sitting on the rail will always beat 4 120lb ers sitting on the rail. Now that's one rule you can really count on. Vic J30 #505 VeeJay
and see if you can tell which works faster. The J30 is very light and depending on wave conditions and sail conditions you will have to find optimums. I am surprised that you would race without the gps to guide you on trim. half the time in 15+ wind conditions the guys around here seem to have the main detuned, because "YOU always sail overpowered in a J30" and it is pretty easy to get to hull speed. I'm betting that you may not see much difference. Of course the key is the helsman's ability to keep the boat maxed out to the wind shifts and wave conditions instead of dicking around with how you have the top batten set ... Maybe on a flat lake with absolute steady wind direction and no current this trim might make a noticeable difference. On a nice windy day in a Jay five 225lb ers ... sitting on the rail will always beat 4 120lb ers sitting on the rail. Now that's one rule you can really count on. Vic J30 #505 VeeJay
If you use a GPS.....
The GPS gives you multiple type of readings, but it will not give you exact speed reading at the exact moment. Because most GPS will acquire the signals and update the speed at specific time intervals. It also will do some minor averaging of your speed. The best is still a knotmeter, which gives you the exact speed and changes up & down instantly.
The GPS gives you multiple type of readings, but it will not give you exact speed reading at the exact moment. Because most GPS will acquire the signals and update the speed at specific time intervals. It also will do some minor averaging of your speed. The best is still a knotmeter, which gives you the exact speed and changes up & down instantly.
I find them both to have their advantages...
and disadvantages. I tend to rely more on the GPS speed over ground than the knotmeter speed through the water. Depending upon tide currents there can be a wide variation, but very helpful to know the difference when you need it.
and disadvantages. I tend to rely more on the GPS speed over ground than the knotmeter speed through the water. Depending upon tide currents there can be a wide variation, but very helpful to know the difference when you need it.
JC ... nice thing about the GPS is that
it confirms windshifts as well as speed changes when trimming. Seems to work well at about 5 second averaging, but it takes a bit longer for the boat to settle to the new trim to really get a solid decision. And it is pretty easy to flip back and forth between trims to confirm the results. In any case when you are dealing within minutes on the same track, we find the GPS proves if there is any tangible difference quickly. The other nice thing is that if all the crew is busy on the rail ... one of the rail meat can be monitoring the hand GPS while hanging on the rail while the trimmer is concentrating on the sail. They chit chat to the optimum, if indeed they can find it. V
it confirms windshifts as well as speed changes when trimming. Seems to work well at about 5 second averaging, but it takes a bit longer for the boat to settle to the new trim to really get a solid decision. And it is pretty easy to flip back and forth between trims to confirm the results. In any case when you are dealing within minutes on the same track, we find the GPS proves if there is any tangible difference quickly. The other nice thing is that if all the crew is busy on the rail ... one of the rail meat can be monitoring the hand GPS while hanging on the rail while the trimmer is concentrating on the sail. They chit chat to the optimum, if indeed they can find it. V
what about currents?
The drawback of a GPS is that it is not at all tied to any currents you may be experiencing. For example, if you enter an area of strong current that is going against you, the GPS will report say that you're going slower, when in reality, you're going the same speed through the water. I find it's useful to use both a knotmeter and a GPS to confirm that any changes in boatspeed are due to either a gust/lull or some change we made to the sails. Then again, if you're not ever sailing in any amount of current, it doesn't really matter which one you use.
The drawback of a GPS is that it is not at all tied to any currents you may be experiencing. For example, if you enter an area of strong current that is going against you, the GPS will report say that you're going slower, when in reality, you're going the same speed through the water. I find it's useful to use both a knotmeter and a GPS to confirm that any changes in boatspeed are due to either a gust/lull or some change we made to the sails. Then again, if you're not ever sailing in any amount of current, it doesn't really matter which one you use.
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