SloopJohnB 157 Posted October 8, 2013 Report Share Posted October 8, 2013 I think there will be a few PT skippers changing where they get their sails from. Quote Link to post Share on other sites
Guest Posted October 8, 2013 Report Share Posted October 8, 2013 I;'m going to answer the original query. How does a 2:1 halyard work? You pull on the end of it and the sail goes up. Quote Link to post Share on other sites
Tubthumper 0 Posted October 8, 2013 Report Share Posted October 8, 2013 I'm not talking about halyard layouts anymore, HOWEVER I learned yesterday that North 3DI sails offer greater mast (fwd/aft bend) support than any other sail construction method. Because they have 90° fibres across the sail offering fwd/aft rig support. So your rig will bend slightly less with 3DI Draw us a picture of how that works Josh…… If I wasn't so busy doing work for you WT I could have shown you that AGES ago. jk Quote Link to post Share on other sites
WarLord 0 Posted October 8, 2013 Report Share Posted October 8, 2013 oh god here we go again.......Really IB do we have to explain the 2:1 halyard thing yet again or can you just go back a few pages? Boo yes please explain your theory again If you put a set of scales under the mast and throw 1:1 - 2:1 - 20:1 or even 100:1 purchase on a halyard, the load (compression) on that set of scales cannot decrease. Youre saying that load (weight) read on those scales will get lighter the more purchase you put on the halyard ??? - Maybe the stays are there to hold the whole shootin match from liftimg off Tell me if Im wrong D. PS . San Fran was a blast, a pretty cool city Quote Link to post Share on other sites
Island Time 786 Posted October 8, 2013 Report Share Posted October 8, 2013 actually it does reduce the compression load induced by the halyard. but of course never by more than the halyard tension . of course the real issue is that BC a standard 1:1 halyard puts twice the halyard tension into the mast! motorbikes diagram on the previous page explains it perfectly.... review that if this is difficult to follow. other diagrams further back do the same. Quote Link to post Share on other sites
WarLord 0 Posted October 8, 2013 Report Share Posted October 8, 2013 actually it does reduce the compression load induced by the halyard. And if that halyard is cleated on the mast ?? D Quote Link to post Share on other sites
Island Time 786 Posted October 8, 2013 Report Share Posted October 8, 2013 if the halyard is terminated at the masthead, without going around a sheave, then the total mast compression induced by the halyard is equal to the halyard tension. this compression is carried in the mast from the gooseneck to the halyard termination at the masthead. if the halyard goes up and around a sheeve, then the compression is twice the halyard load, unless it is a 2:1 halyard.... Quote Link to post Share on other sites
B00B00 171 Posted October 8, 2013 Report Share Posted October 8, 2013 sorry I really cant be bothered going throught it all sgain. But all I can say its a fact so just think about and/or read back a few pages.. Quote Link to post Share on other sites
RushMan 28 Posted October 8, 2013 Report Share Posted October 8, 2013 Simple way to tell... Try hoisting your mainsail without the 2:1 and you will feel the difference. More rope to pump but the effort required is less with the 2:1 Quote Link to post Share on other sites
wheels 404 Posted October 11, 2013 Report Share Posted October 11, 2013 Sorry Booboo, but you and several of you are quite wrong on this. You do not reduce the mast compression no matter how many purchases you have. The Mast compression comes from the tension you have in the luff of the sail plus the weight of the Sail material itself. Lets say that total load is 100Kg. 1:1 will see 100Kg on the halyard also. But that does NOT Sum to make 200Kg of mast compression. It is 100Kg @ 1:1 = 100Kg on both sides. 2:1 simply makes the Halyard tail "see" 50% of the 100Kg. But the Sail side of the halyard never changes. The sail and the halyard still exerts 100Kg from the top of the mast sheeve to the foot of the sail where ever the point of connection of the bottom of the sail is. eg, the Gooseneck. Quote Link to post Share on other sites
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