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winter projects and upgrades


tonyquoll

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Thinking about some upgrades and wondering about these:

Vang mast rotation control:

Heard that with the new NZ style: "The vang pressure works in a couple with the gooseneck fitting to hold the mast at its rotated angle. The rotation is a secondary limiting control to the vang"

You what?

Boom:

I'm making a new boom out of a bent USA section mast, and looking to optimise block placements. Also thinking about streamlining; how about ducting air through the boom to reduce turbulence & increase lower sail performance?

Carbon bits:

Looking to experiment with carbon-fibre moulding, and thinking of:

- rudder pintles, to replace the SS ones that always work loose; liking the big NZ C-shape one

- boom gooseneck; to replace the solid Al plug. Does this tie in with mast rotation device?

- outhaul car; what about a carbon sail slug with impregnated roller bearings?

- foils; if time/$/ability allows. And carbon centreboard casing to retro-fit skinny boards into the hull

- trick rudders; what if the foils curved as they turned, like a miniaturised C-Class wing mast? Phwoarrrr

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Yes Tony you do have too much time on your hands.

I'm currently making a new boom with outhaul based on Marcovitch design which doesn't require cars or bearings or anything apart from another eyelet about 100-150mm up from the foot and a slug on the lower eyelet.

Gooseneck plug - Yacht Shop sells Riley fitting RM677/RM678 (not sure which one I bought) but it was only $20 - http://www.rileyfittings.com

I'm almost ready to make a mould of a plug for centreboards. I have everything I need to make a few sets - all the tools and materials.

All rotation devices I've seen work - Marcovitch design is probably the simplest with a 4 sided spanner.

I've finally got my boat back together after NZ - did a few repairs and mods smile.gif

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Guys, This sounds all well and good but does anyone ever think about us fringe dwellers that never get to see upfront these new ideas in action and have to try and study them from a few photos (if that). When is someone going to add this type of infromation to the paper tiger web site so that all can be excited and not just those who went to NZ?

I'm all for trying something different just to see what happens.

Gary F

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Thanks for the replies. Winter is so boring! Without sailing I'm still dreaming about sailing; wishing I did have too much time to enact all these ideas.

Gary there's great pics and info at http://www.papertigercatamaran.org/ under the 'help and advice' section. Most if it's in pdf files though

Some of Rachel's great photos taken at Napier can be seen at: http://www.papertiger.org.nz/Gallery.htm

I'm still not getting how their mast rotation / vang is different from the usual. In this photo of the NZ National Champ Bob Preston, the vang looks normal: Inter2010web_DSC_6850_RLeatham10.jpg

[This message has been edited by tonyquoll (edited 19 June 2010).]

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Vang_MK1.JPG

I'm guessing:

- not shown off top right is some vang tension adjuster. More ropes & cleats?

- vang tension would have some force pulling this straight, but the boom pressing on the gooseneck would be a greater force rotating the mast

- the rope shown can limit mast rotation

Can anyone explain?

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Possibly this shot shows the system in action: Scott Pederson on "Bad Boy". This is an amazing boat with carbon-fibre internal bracing, carbon moulded bits everywhere! If anyone has the latest trick bit, I'd expect to see it on this boat.

It looks like there are red & blue lines leading from the vang:

PTs2010-DSC_5496-RLeatham1%20copy.jpg

PS; Great photos Rachel!

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G'day Tony

The vang tension does NOT pull the spanner straight. The little system shown does.

Off to the top right is a standard set of vang blocks, which effectively determine how much the boom is able to lift, especially once the boom is out past the back beam. The little system is eased to allow more rotation or tightened to allow less rotation.

I haven't used it myself, although Jon Pinkerton developed something similar last year.

Regards,

Dave.

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  • 1 month later...

I like design & engineering, so for me understanding and developing new concepts is fun. There are a few talented craftsmen around that can make the custom bits for paying customers who don't enjoy the challenge.

Although PTs are a one-design class, these little tweaks make a tiny difference. For master sailors at the peak of their game, the difference can be winning or 2nd place. In real terms that's a few seconds after an hour's racing. More regular sailors probably wouldn't notice any difference.

I don't see these custom fittings as frustrating, more that it is part of what makes Paper Tigers great racing boats, as opposed to those mass-produced plastic toys others sail wink.gif

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It does seem wierd that such a complicated system as that vang is encouraged by the skipppers.

Ten or so years ago i put a system on my boat the automatically adjusted the outhaul when i adjusted the downhaul. It used off the shelf parts, and cost less than $20 to adapt from my existing system. The wording of the rules was changed a year later and prohibited that system.

My least favourite part of sailing is pulling all the different ropes as the wind changes, so the PT is perhaps not the best choice of boat for me! I think one of the better things i have done in the last few seasons is get the right rope for the traveller that has just the right stretchyness to dump the traveller the amount i like when a gust hits without me touching it.

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