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Why slack rigging |
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ColH
Far too distracted from work Joined: 11 Jan 06 Location: United Kingdom Online Status: Offline Posts: 242 |
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Topic: Why slack rigging Posted: 06 Feb 17 at 8:20pm |
There's a fair few threads on here which allude to some classes which favour slack rig tension. I'd like to understand the reason(s) why this is preferred, what's the technical reasoning?
Edited by ColH - 06 Feb 17 at 8:21pm |
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Rupert
Really should get out more Joined: 11 Aug 04 Location: Whitefriars sc Online Status: Offline Posts: 8956 |
Post Options Quote Reply Posted: 06 Feb 17 at 9:07pm |
Because it is faster...
In the case of the Firefly, it allows the rig forwards offwind and back upwind, using job tension and kicker/mainsheet. Sails are cut for this to work, as it means old wood hulls aren't pulled apart. |
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Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686
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Sam.Spoons
Really should get out more Joined: 07 Mar 12 Location: Manchester UK Online Status: Offline Posts: 3398 |
Post Options Quote Reply Posted: 06 Feb 17 at 10:19pm |
It seems that on singlehanders like Solo, Streaker and Blaze (and others) the slack shrouds allow the boom forward enough to allow by the lee running. If you want an extreme case just look at a Star bearing away onto a run. If a boat has a spinnaker and/or trapeze(s) a certain amount of rig tension is required to keep the stick in the boat.
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sargesail
Really should get out more Joined: 14 Jan 06 Location: United Kingdom Online Status: Offline Posts: 1459 |
Post Options Quote Reply Posted: 06 Feb 17 at 10:48pm |
And the other thing that happens is that the leech is opened.
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Paramedic
Really should get out more Joined: 27 Jan 06 Location: United Kingdom Online Status: Offline Posts: 929 |
Post Options Quote Reply Posted: 07 Feb 17 at 8:09am |
On some of these classes (Solo) the rig is essentially unstayed, with the shrouds/forestay used to limit the amount the mast can bend. When these classes were first designed it was probably a much cheaper way of doing it than a bespoke unstayed alloy mast like in the Finn/OK and more robust than the unstayed wooden spars in the same classes. These boats were designed to be built (or at least finished) in your garage/living room/kitchen so the latest hi tech stuff was neither accessible or appropriate and in those days may not have been significantly better.
Nowadays you wouldn't do it, but it was how things were done in those days. It works so nobody has bothered to push for rule changes. I may be doing Mr Holt down slightly, but things like getting the boom out squarer were probably more convenient side effects than design features! Fittings, ropes and in many cases hull structure were not up to rig tensions of the sort that we run today.
Edited by Paramedic - 07 Feb 17 at 8:12am |
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Sam.Spoons
Really should get out more Joined: 07 Mar 12 Location: Manchester UK Online Status: Offline Posts: 3398 |
Post Options Quote Reply Posted: 07 Feb 17 at 9:11am |
I'd be interested to see a 1960s tuning guide for a Solo. I have no firsthand experience (though I'm just about old enough) but I suspect Solo rigs were designed to have some tension originally particularly as the first boats had wooden masts. I doubt anybody would have tolerated a slack rig by today's standards.
I do remember that sailing by the lee was absolutely beyond the pale, nobody in their right mind would allow it to happen so you may well be right that JH would't have considered that an issue. Edit :- this is a fascinating read http://www.strawberrymarketing.com/publishing/firefly75/FIREFLY%2075%20years.pdf but notice the boat in the first pic has diamonds so unlikely to be a slack rig.
Edited by Sam.Spoons - 07 Feb 17 at 9:26am |
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Rupert
Really should get out more Joined: 11 Aug 04 Location: Whitefriars sc Online Status: Offline Posts: 8956 |
Post Options Quote Reply Posted: 07 Feb 17 at 10:15am |
On Firefly Reynolds masts (the ones with the wooden top) diamonds were tight, but shrouds loose. The mast rotated, so tight shrouds would have prevented that happening easily. Once the rotating Proctor mast came out, they were so stiff, even the diamonds became slack.
Edited by Rupert - 07 Feb 17 at 10:16am |
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Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686
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Sam.Spoons
Really should get out more Joined: 07 Mar 12 Location: Manchester UK Online Status: Offline Posts: 3398 |
Post Options Quote Reply Posted: 07 Feb 17 at 10:19am |
Interesting stuff Rupert, I don't have a desire to own another old wooden boat but it's fascinating reading about them.
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iGRF
Really should get out more Joined: 07 Mar 11 Location: Hythe Online Status: Offline Posts: 6496 |
Post Options Quote Reply Posted: 07 Feb 17 at 12:01pm |
Having floppy rigging enables the rig to act a little bit like a racing windsurfer rig, i.e back for upwind and forward for off wind, it also helps in light wind enabling soft sails to heel and keep shape without having to heel the boat on hulls that don't like to be heeled.
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Sam.Spoons
Really should get out more Joined: 07 Mar 12 Location: Manchester UK Online Status: Offline Posts: 3398 |
Post Options Quote Reply Posted: 07 Feb 17 at 1:07pm |
It looks like the very extreme forward rake of the Star class downwind gets the airflow moving up the sail and, maybe, keeps it attached for longer?
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