[quote=MN3]From an earlier discussion
[img]https://www.catsailor.com/bb_files/11514.gif[/img]
[quote]I disagree with those calculations... The sail gets a tension of T on all three cases. The 2T and 1.5T apply not to the sai[b]l [size=large]but perhaps to the mast head[/size],[/b] wich is of little interest. The most relevant is that you need half the tension on the halyard (and double the lenght and time to raise) in picture 2. Also interesting is that in picture 2 the mast head pulley gets half of the load compared to picture one. If you want to apply constant tension with the full halyard that is relevant too.
Picture 1 compared to picture 3 is interesting if the halyard goes down through the mast track. Imagine that it's a dyneema halyard attached at the base of the mast instead of a hook at the top, and you have a 10:1 (or less perhaps) downhaul. Then you double the effect of the dowhaul: 1T on the sail and 1T on the halyard, except that now T may be amplified with the downhaul. With other kind of line all this theory is defeated with the stretching of the line, of course. Which I bet it's the original reason why there is a hook, even on old boats without a powerful downhaul. But as said, it may sound good but you don't want to apply all that tension on the mast head pulley, you will likely break something there.
On the other hand, if the halyard goes down at the front of the mast, as hannes-neo explains, the effect of the downhaul is canceleed by the tension of the halyard in front of the mast. Unless the fork is installed near the mast head, in front of the mast, as it is meant to.
Edit: hope you didn't read in between my edits...[/quote]
yes the forces on the sail / luff are the same, but on the mast (head) they are increased[/quote]
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