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Phils Rig School continued...

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G.R.F. View Drop Down
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    Posted: 25 Nov 09 at 8:14pm
Since those irritating three initials flamed up the other thread, before we
really talked the whole thing through and there was one thing that we
used to borrow from dinghies back in the days of flexi needlespars.

Topping Lifts.

Anyone remember them?
Line from the end of the boom to the tip of the mast, kind of exactly
opposite force to the boom vang as it was more generally called then.
Tightening it flexed the mast tip and released the head of the sail to get
that twist. It was going through my head as a possible extra source of
stay to counter the pull of a kite on an unstayed rig, least that's what I'd
been thinking before things went awry.

Anyway, are they still about, anyone use them?
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Villan View Drop Down
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Post Options Post Options   Quote Villan Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 8:23pm
I thought a topping lift was something you had on yachts, used when you were lowering sails as it held the boom up in the air while you did so, and meant the boom didnt drop on the deck etc.

Did think that someone somewhere might use it as a "reverse kicker" to lift the boom up and open the head of the sail, but then wondered .. "whats the point? you can just let the kicker off" ..

And that was the last I thought about it.

As to using one to pull a mast head back and support it using the boom+vang .. what happens when you are going downwind and have to ease the main? Surely the force of the wind on the top of the main, combined with the pull of the "Topping lift" pulling against the vang, could break the mast? (Hence one of the reasons they tell you to let the kicker off downwind)

I could be entirely wrong of course, so can someone who knows what they are talking about pick my points up and correct them?

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Post Options Post Options   Quote Lukepiewalker Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 8:59pm
Mirrors have allowed them a few years back. Generally of use in very light winds when the weight of the boom holds the leach closed, I believe used only sporadically to reattach flow. A problem also solved in other classes with loghter carbon booms. The problem with ones from the boom end to the mast head is all that pesky roach getting in the way, so I think the Mirrors were just using the pole uphaul.
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G.R.F. View Drop Down
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Post Options Post Options   Quote G.R.F. Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 9:08pm
Well I hate to mention the crazed mans name, but I swear I caught a
glimpse of some device at the head of a mast on one of that Doug Lords
rig pictures ages ago.

A bit like that temple vang deal only at the head of the mast.. I may have
got it arse about face, it was just a casual glance scoping through some
pics of his when i was trying to figure out what made him tick and the
man behind the forum facade.

This is all speculative here Villan, nothings right or wrong, just
brainstorming for fun.

Trouble is the idea falls down as you rightly point out, the kickers off
down wind.

But i did wonder if topping lifts still existed in any of the older classes.
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Post Options Post Options   Quote Rupert Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 9:30pm
Would a backstay make more sense, yotty style?! Model yachts solve the problem of the roach by having a 90 degree bend at the top of the mast to take it clear before coming down. Tuning the backstay is/was an important tuning thing in yachts.
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Post Options Post Options   Quote alstorer Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 10:21pm
No, you're right, Doug's "Aeroskiff" did apparently have some sort of topping lift crane on it- think even the level headed opinion was that it was yet another thing he was badly badly wrong on, at least with regards rig design for an efficient foiler.

This does need yotty input though- they're the ones most likely to have one, as as said it rather helps for reefing.
-_
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Post Options Post Options   Quote winging it Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 10:30pm


the kicker on this boat is formed by being an extension of the boom, which has passed through the mast.  As you pull on the end of this extension the end of the boom is forced down, replicating to some degree the action of a conventional kicker.  Presumably you could also fit a devie that would have the reverse effect ie oulling the boom up. 
the same, but different...

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Post Options Post Options   Quote Phil eltringham Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 11:10pm
the resons for not bothering with one (on dinghies) are too numerous, and too obvious to waste time discussing, really, you could have come up with something more of a challenge

Edited by Phil eltringham
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G.R.F. View Drop Down
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Post Options Post Options   Quote G.R.F. Quote  Post ReplyReply Direct Link To This Post Posted: 25 Nov 09 at 11:34pm
O.K. here's my next brainstormer.

My thinking was a two part mast system, with an inner and an outer.

The outer sleeve if you wish, it'll be difficult to describe this without
drawings.

But imagine a horse shoe style section of carbon in monocoque form, so
it's as stiff as the proverbial stiff thing, but the 2nd part, that the sail is
sleeved on/boltroped to whatever, has variable luff curve potential for
and aft.

Kind of bendy inner windsurf style mast (like the current rdms, ony
maybe a tad thinner)sleeved by permanent dont even try and change
shape outer.

That way the sail maker could set his bend curve to an inner of his choice,
and the outer remains universal. Less dicking about.

Now with the outer not having to be bent or buggered about it could do
useful stuff like twist to weather, or even slide back and forth a bit further
than is current.

I dunno, just a thought. Kill a couple of birds with one stone, standardise
the outer whilst leaving the inner at the sailmakers disposal.

Built in decent carbon shouldn't be too heavy, Might be a bit pricey, but
then if it really did the deed and you could get the sort of depower
windsurfer rigs are capable of, who knows...

Just a thought - damn dangerous this - sounding like a nutter and
mentioning Doug Lords name in the same thread.



Edited by G.R.F.
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Post Options Post Options   Quote alstorer Quote  Post ReplyReply Direct Link To This Post Posted: 26 Nov 09 at 7:08am
Drawings really would help I reckon. Sounds like you're doubling the weight of the mast though.
-_
Al
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