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Puzzle: Name That Detune

Posted in Puzzle

A client recently called for a consultation on tuning. He has a 30-something-foot contemporary sloop, double-spreaders, with all the shrouds even with the mast (athwartships). That might sound impenetrably salty for the non-sailors here, but it just means that there are three shrouds (lateral stays) on each side of the mast. The upper two shrouds go over spreaders, which are just struts that create a good angle to the mast. The lowermost shrouds go straight to deck. Checkstays and babystay omitted for clarity. See my illustration above, which simultaneously shows the rig’s configuration and explains why I use actual illustrators for my books.

My client had started by tuning the uppermost shrouds first. This is a red herring. Please do not be distracted by it. But I would always tune the lowermost shrouds first on this rig.

Not distracted? Good. So he got the tension he wanted on the uppers, and went to tension the next ones down, the intermediates. After he had done this, he re-checked the tension on the uppers, and was puzzled to discover that they were significantly slacker than they had been. This is not supposed to happen.

And here is the puzzle: How many possible reasons can you think of for why those upper shrouds lost tension? You only need to come up with one believable explanation to qualify for a Fabulous Prize, but we will have a separate, Also Fabulous Prize for the person or group that can come up with the most answers that, in my utterly subjective opinion, make some kind of sense. Your rigging can be made of wire, rod, or synthetics, but to reduce variables let’s say the mast is aluminum. You can assume your rig is anywhere in the world, at any time of year you like.

Deadline for entries is noon Pacific Time, Monday, May 28th. Send your entries to:

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Fair leads,

Brion Toss

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  1. Peter Hennessey
    Peter Hennessey

    Two possible but similar reasons spring immediately to mind, either the mast supports of whatever type they may be are compressing under tension, or the chainplates/deck/hull sides are pulling upwards. Tuning from the bottom up could help avoid overtensioning the rig. Maybe slacking things off and retuning would help, but once you’ve sprung the hull/deck/mast step the damage may be permanent…

    May 24, 2018

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