which end to cut for Dory Lug mast?

I am pretty sure I know that the answer to this question is that it doesnt matter or matter much (if it did I suspect that the manual would have said something already). But I am about to cut the tappers on my mast for the Dory (lug rig) and they are not the same on the top and bottom. So once I do this I am choosing the orientation of the mast. I also note that the scarf is also not in the middle. So that raises the question of whether anyone has found any reason to care about whether the scarf joint is on top of the mast or towards the bottom. I think that the greater stresses are likely to be on the bottom where the mast meets the thwart and where cleats are installed. But i have a feeling that the scarf joint end may being stronger in rigidity, but less flexible. on the other hand, the top of the mast will be somewhat thinner. Hence the question.

 

(if anyone has had an issue finding a perfectly flat level space (old house, nothing is level or straight) to glue the mast and spars scarfs together so they come out straight I found that putting down pastic sheeting on whatever surface you have under the mast, and then slidding index cards one by one under the sheeting at various spots along the mast, adding and experimenting until a long straight edge sitting on top shows no air between mast and edge along the scarf joint, works very well. once level and straight, you separate the two pieces by rolling them 90 degrees away from eachoether, add the sauce, then roll them back and clamp)

thanks


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RE: which end to cut for Dory Lug mast?

I asked john about which piece up long or short for the (aluminium)passagemaker/Skerry Gunter Sloop rig mast.

This iwas his answer:

"I would put the short piece of mast towards the top. At an
engineering level I don't think it makes any difference. But since
the location of the joint influences the bend of the mast under
sailing loads, and the shape of the bend is a tiny bit more ideal for
the sail shape if the joint is up high, I'd put the short piece on
top."
 

Ruud
 

RE: which end to cut for Dory Lug mast?

thanks, my take away from that comment is that there is no structural reason to care. in the case of a sloop rig it impacts sail shape so put the scarf on top. in the case of a lug rig the sail is not in contact with the mast so I believe, based on what youve said, it would not matter in the least which end is on top, the shape of the mast has no impact on the shape of the lug rig sail.

 

Anyone disagree or have thoughts?

 

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