Centre main.

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neil
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Re: Centre main.

Post by neil » Sat Sep 05, 2015 3:47 pm

Fixed it
Nessa wrote:Image
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Michael Brigg
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Re: Centre main.

Post by Michael Brigg » Sat Sep 05, 2015 7:23 pm

Nessa, you need to put the link between the two "[URL]'s"

Presently it is sitting " [URL] [Here URL]."

Time for ready readers I fear! :D
Michael Brigg

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Re: Centre main.

Post by jpa_wfsc » Sat Sep 05, 2015 9:47 pm

Back to the Aquabat... I notice you have a pair of SS plates on the gunwhales at the stern... these are where you would fix the laser style bridle.

I also notice that you have a plastic rowlock style gooseneck fitting. I would be astonished if that survived the loads created by a powerfull enough kicker to control the sail properly with a centre main. With the laser type stern bridle approach, the downwards pull that you need to shape the sail correctly upwind, would produce almost no down/forward load on that gooseneck. Also given the size of the boom / mast tube I suspect any cascade type powerful kicker is just going to bend the boom rather than pull it down, and this will effectively work like letting the outhaul off.. more power, not less.

All in all - I would advise something closed to the original approach?

j./
j./

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trebor
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Re: Centre main.

Post by trebor » Sat Sep 05, 2015 10:06 pm

Hi Nessa,
You can still access your image via what you have mis-printed, just highlight forwards from http to end of jpg, then right click, it will ask you if you want to go there.
I can see this reducing down force from mainsheet, but it could bring about block to block issues when sheeting in.

Hi John,
I have powered a 32to1 kicker through a rowlock gooseneck, most of the force appears to push boom into mast rather than down.
The boom on Sprint is 65mm diameter, it does not bend.
I wanted a centre main system, because I cannot stop main sheet dropping over corners and rudder when using centre/aft system.
Robert
Minisprint 4230
Tinker Traveller 160
Mirror 61147 Anastasia
http://www.aquabatdinghy.co.uk

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Re: Centre main.

Post by Rupert » Sun Sep 06, 2015 8:23 pm

The goosenecks are surprisingly strong, John.
Rupert

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Re: Centre main.

Post by jpa_wfsc » Fri Sep 11, 2015 12:22 pm

Well - OK but I broke one on a sailing school topper once!
j./

National 12 "Spider" 2523
Finn K468 'Captain Scarlet'

British Moth, 630, early 60's 'Pisces'

!!!! Not CVRDA !!!!
Comet Trio - something always ready to sail.

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Re: Centre main.

Post by Nigel » Fri Sep 11, 2015 3:52 pm

Sitting on it doesn't count :P

Could have been degraded and made brittle by UV.

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Nessa
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Re: Centre main.

Post by Nessa » Fri Sep 11, 2015 4:12 pm

We have a lot of such gooseneck on our ancient toppers, the force on them lRgely pushes them onto the mast, so they last well..
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Re: Centre main.

Post by JimC » Fri Sep 11, 2015 4:25 pm

One should remember that the design task for those rowlocks is not a light loading...

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Re: Centre main.

Post by jpa_wfsc » Fri Sep 11, 2015 8:44 pm

Nigel wrote:Sitting on it doesn't count :P

Could have been degraded and made brittle by UV.
I think it probably was, or else flawed when moulded: one of the jaws snapped off on a beat.
j./

National 12 "Spider" 2523
Finn K468 'Captain Scarlet'

British Moth, 630, early 60's 'Pisces'

!!!! Not CVRDA !!!!
Comet Trio - something always ready to sail.

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Re: Centre main.

Post by trebor » Fri Sep 11, 2015 9:01 pm

Looking at photo again, I could see this working, what about using this approx' a third of way up boat from stern, then feeding mainsheet forward to where existing control is ?
The tiller would be fed through horse similar to Laser, would their be sufficient travel for tiller?
Robert
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Nessa
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Re: Centre main.

Post by Nessa » Fri Sep 11, 2015 9:28 pm

Or just defy convention and go aft main? Tacking and gibing would be easier, given the position if the seat.
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Re: Centre main.

Post by realnutter » Fri Sep 11, 2015 9:46 pm

Nowt wrong with an aft main!

Watching Amy sail her ToY in very light air at Shearwater was funny.. She was sitting forward of the sliding seat, and hence forward of the centre main, to stop the transom dragging...

Tacking was tricky!
Matt

Int Moth K2992

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trebor
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Re: Centre main.

Post by trebor » Fri Sep 11, 2015 10:03 pm

Difficult to panhandle, when you are so far forwards :D
I have been sailing my Enterprise which is aft rigged, I always associate aft rigged boats with light wind sailing, and older style boats, when was the last boat to use aft main, designed ?
Robert
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Re: Centre main.

Post by Rupert » Sat Sep 12, 2015 8:22 am

I used aft main on my Sprint years ago, works fine. There are still plenty of aft main boats out there, including modern National 12s and the Minisail championship winning boat... Fashion is a funny thing. Toppers are a great example of a boat which may well be quicker as aft main, especially for an adult or large teen, but the centre main option has taken over in racing completely.

I did a season in the Lightning with an aft main set up, just for the hell of it. Much nicer in the light stuff, just plain scary to gybe in a blow. But the Minisail gybes like it on rails anyway in comparison, so this would be less of a problem.
Rupert

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