Dinghy development: Mainsheet bridles

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Mainsheet bridles

Printed From: Yachts and Yachting Online
Category: Dinghy classes
Forum Name: Dinghy development
Forum Discription: The latest moves in the dinghy market
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=11863
Printed Date: 10 Jul 25 at 1:43pm
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Topic: Mainsheet bridles

Posted By: pondlife1736
Subject: Mainsheet bridles
Date Posted: 21 Jan 15 at 1:57pm

This leads on from the Melges 14 thread which turned into an interesting discussion about bridles.

So my EPS has a Laser type floating pulley on the centre bridle, whereas some boats like Phantom, RS300 have the pulley pinned at the centreline.

What are the pros and cons of each type?

I can see that the centre pinned bridle changes the sheeting angle to be more horizontal which I would have thought was a good thing.

Is there any advantage to the floating arrangement?

As an aside, I've always found the EPS sinks its tail when I move my not inconsiderable bulk behind the mainsheet through the tacks. Attempts to cross ahead of the mainsheet have not been elegant! Then I tried the D0 with its rear bridle and off boom sheeting, an arrangement I hadnt tried before. This was such a revelation in allowing me to keep weight forward that I'm now considering converting the EPS to rear bridle.

Replies:

Posted By: maxibuddah
Date Posted: 21 Jan 15 at 2:34pm

The phantom may have it tied on the centre strop but it is deliberately long so that when you sheet in it is off centre preventing you from over sheeting. As the rig is dropped back the boom is further out but this isn't a problem because you are depowering big time by that point.

Certainly a rear bridle is better for keeping the boom where you want it but then you have a lot more mainsheet...normally. But you can get away with 1:1 on the front sheet because the purchase is on the back. On normal centre sheeting boats you'll need 3:1 or 4:1 as there is less moment to pull against.

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Everything I say is my opinion, honest

Posted By: pondlife1736
Date Posted: 21 Jan 15 at 3:33pm

Good point, I'm even thinking about 1:1 at the rear since I tend to use it in lighter winds. By my calc that is 1/3 higher sheet load than the current centre 4:1, but of course less to pull in.

The real question though is why the pinned bridle attachement on the Phantom whereas the EPS has the traveller pulley? Something to do with stayed vs unstayed rigs?

Posted By: rb_stretch
Date Posted: 21 Jan 15 at 3:34pm

Originally posted by pondlife1736

That is exactly how I had to sail the D0 to not sink the tail. Not sure why more boats (especially singlehanders) don't put the mainsheet further forward. Was looking at the first Aero to arrive at our club and was also thinking how far back the mainsheet is.

Posted By: JimC
Date Posted: 21 Jan 15 at 3:51pm

The fixed position for the bridle with vang sheeting was originated in the late 70s, I believe by NZL 470 sailors, but it didn't become widespread until much much later. It might well be simply that it wasn't mainstream enough for the EPS development team.

Posted By: jeffers
Date Posted: 21 Jan 15 at 4:23pm

The Blaze (when I had mine) you had a floating block on the bridle but had stop knots to limit how far along the bridle the block could go.

They now allow a rear bridle which gives far better control and allows for off the boom sheeting (meaning you can keep your weight much further forward). The D-Zero does not seem to sink the transom in my experience and you can pass through the gap 'Laser style' should you need to.

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Paul
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D-Zero GBR 74

Posted By: Woodbotherer
Date Posted: 21 Jan 15 at 4:36pm

I rigged my EPS off a rear bridle for the same reason you state, having to go round the back and digging the stern in, tacking isn't the speediest thing an EPS does at the best of times.

But, I've gone back to centre sheeting but with a traveller I fashioned out of garden hose to keep all that gubbins from getting caught round the mainsheet block and tower.

The reason I didn't like it was because the sheer weight of all the main sheet especially in light airs, made keeping the sail sheeted out or forward when trying to run by the lee. I also suspected that I was choking the sail by over sheeting upwind, difficult not having another EPS to sail alongside, but my performance against Lasers and Roosters is pretty measured and I didn't fair anything like as well as I do now, with rear sheeting.

And the rope doesn't get tangled with the wiggle stick anything like as often as it did when it was all down the back.

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http://www.edgeactionsports.co.uk/collections/soundcast-portable-weatherproof" rel="nofollow - Soundcast Weatherproof Speakers

Posted By: pondlife1736
Date Posted: 21 Jan 15 at 6:42pm

I can but try I suppose. It looks temptingly easy to use the outer fixings on the wing rear tracks; they are more or less level with the end of the boom. No need to drill holes in the boat.

Floating pulley or centre pinned bridle though??

Another bonus is I have to fold the t/extension backwards when tacking as it's too long to clear the centre main. A small point perhaps, but irrationally annoying........!

Posted By: Do Different
Date Posted: 21 Jan 15 at 7:31pm

Probably floating would be best, very rarely does a mono rig need sheeting to the centreline. Centre lining the boom may possibly give the feel of pointing high but is usually slower and perhaps even result in a lower course because even though the boat is pointing high the foils are moving so slowly they are stalled and making lots of leeway.

Posted By: craiggo
Date Posted: 21 Jan 15 at 7:52pm

Take a look at the Musto Skiff. It has a floating block on a loose bridal. RS700 has a fixed centre bridal. Both work although I've never tried the skiff style setup on the 700 to see if it makes a difference.

Posted By: RS400atC
Date Posted: 21 Jan 15 at 8:13pm

Don't contenders use a block floating on the bridle?
I think there is a balance between allowing independent control of sheeting in and leach tension, vs wanting to control both together?
As you ease the sheet in a gust, you want to allow a little more twist?

Posted By: Woodbotherer
Date Posted: 22 Jan 15 at 9:41am

Originally posted by Do Different

Probably floating would be best, very rarely does a mono rig need sheeting to the centreline. Centre lining the boom may possibly give the feel of pointing high but is usually slower and perhaps even result in a lower course because even though the boat is pointing high the foils are moving so slowly they are stalled and making lots of leeway.

I think this is what happens. I fixed a pulley block centrally on spectra line tied off to the ends of the rack tracks. When I saw the Punk I was going to try and fashion something along the lines of that but in the end a nasty clew first stack and the nose of the boat somehow getting between the boom end sheet and the stern convinced me after a nightmare trying to sort it all out in the water, to go back to centre sheeting.

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http://www.edgeactionsports.co.uk/collections/soundcast-portable-weatherproof" rel="nofollow - Soundcast Weatherproof Speakers

Posted By: JohnJack
Date Posted: 22 Jan 15 at 12:23pm

It works a bit differently on the Laser IMHO.

Before the new kicker arrangement you would to some extent control mast bent with the main sheet (maybe this is an un-stayed rig thing).

Upwind is always block to block bending the mast as much as possible

(probably a bit different now there is sensible purchase on the kicker).

The Laser rig is also pretty unsophisticated and I don't think the same level of thought was put into it as the likes of the Zero, Aero, Blaze etc etc (modern boats).

Also being a strict One Design, not much changes quickly (eg the sail)

Posted By: PeterV
Date Posted: 22 Jan 15 at 12:30pm

The Laser is a bit different. Before the new kicker came in the sheeting angle couldn't be adjusted, if the bridle was eased the angle reduced but then it was too narrow, so the bridle was always tight. Since the new kicker it's been possible to tighten the kicker and ease the main, increasing the sheeting angle whilst still keeping a flat sail and this has allowed more efficient sailing in stronger winds.

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PeterV
Finn K197, Finn GBR564, GK29
Warsash