Technical Committee announces new test of stern bridle

[Ed "Buttons" Padin, Class Administrator]

Many Viper owners have re-rigged their main sheets by moving the bridle from amidships to the stern, immediately in front of the split tails of the mainsheet—using the same deck pad eyes. Over half of the boats at the 2018 NAs used this aft bridle/aft split tail set up. While this makes trimming the mainsheet much easier, the size of the triangle created by the two sides of the bridle (through which the tiller passes) can reduce the range of side-to-side tiller movement, and accordingly, the ability to make sharp turns. This has been raised to the Technical Committee (TC) as a concern by several owners.

The TC has gotten approval under Rule 10.13 for all owners to test a new aft bridle configuration to address the issue and lead to a possible rule change in the next rules cycle. We welcome your feedback.

[Dave Nickerson]

Suggest that anyone who's had concerns about the stern bridle limiting their steering to give this set up a try. It's easy to rig and very effective. We've been testing it for half the summer in local PHRF sailing. It works really well.
Dave

[Peter Beardsley]

Dave,

Given that the lines to pull the split tails off to the side are not allowed during this test, it seems like the fundamental "problem"* remains for those who opt for aft sheeting - there are still tails aft that can hit the tiller.  How much "space" do you estimate that you created with this system - 2 more inches side to side?  It doesn't seem like much from the photos.

* Note: I personally don't think this is a huge issue and we're creating a crazy looking transom for minimal benefit, and am unlikely to participate in the test unless I am underestimating the benefits. 

[Dave Nickerson]

Peter - The bridle almost always gets set up lower than the split tail, some set it up much lower. And until the main is out a bit, both legs are tensioned with 2 parts of the mainsheet load. This creates a much smaller triangle, higher loads and a more restrictive constraint for vertical rudder/curved tiller movement. This test set up eliminates any constraints from the aft bridle.

My experience is that the split tail is much less constraining. The windward split tail is relatively easy to push out of the way with the tiler if you ease the main some (it's carrying only one part of the mainsheet load). And the leeward tail goes loose when you let the main out a little.

I noticed a big difference, but encourage others to try it.

The ultimate solution is new rudder with a head at right angles to the leading edge so we can go back to using a straight tiller.  Until Rondar produces that or for folks who don't want to buy a new rudder, this is an interesting option.

[Steven Haywood]

What are the advantages of a stern bridle over the centre bridle with stern split tails? Just less clutter amidships?

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[Peter Beardsley]

Center bridle pros:
- Theoretically cleaner to bring main to centerline without adding leech tension
- Have a bridle nearby that the skipper can use to pull himself in and out of the boat if needed
- Easier to grab a short purchase downwind to feel pressure in the main and/or pump on waves
- Easier to throw the boom across on gybes

Center bridle cons:
- Harder for skipper to transit fore and aft in lighter air - need to jump over a bridle
- Not as much leverage to trim the main in heavy air (this one is big for a lot of people)

Aft bridle pros/cons - pretty much reverse the above.  The two cons for the center bridle are two major pros for the aft bridle that we think negate any disadvantages of the aft bridle.  Aft bridle is becoming more popular among top teams for that reason - much easier on the skipper to play the main in big breeze, and we don't end up pumping the main all that often in a Viper downwind (you're planing, not surfing), and we don't think it's that hard to flick the boom across or need something to grab to pull yourself in. 

[Peter Broszkowski]

My experience was that if I just eased the mainsheet more  in sharp turns it solved the problem. The split tail is then just slack enough not to limit the tiller.

[Justin Scott]

Center bridle pros:
- Theoretically cleaner to bring main to centerline without adding leech tension
- Have a bridle nearby that the skipper can use to pull himself in and out of the boat if needed
- Easier to grab a short purchase downwind to feel pressure in the main and/or pump on waves
- Easier to throw the boom across on gybes

Center bridle cons:
- Harder for skipper to transit fore and aft in lighter air - need to jump over a bridle
- Not as much leverage to trim the main in heavy air (this one is big for a lot of people)

Aft bridle pros/cons - pretty much reverse the above.  The two cons for the center bridle are two major pros for the aft bridle that we think negate any disadvantages of the aft bridle.  Aft bridle is becoming more popular among top teams for that reason - much easier on the skipper to play the main in big breeze, and we don't end up pumping the main all that often in a Viper downwind (you're planing, not surfing), and we don't think it's that hard to flick the boom across or need something to grab to pull yourself in.

Good analysis by Peter.

The center bridle has two major benefits downwind. 

1. You can take the main sheet direct from the block on the boom and change from 6:1  to 2:1 in an instant.  This makes it much easier to feel the pressure on the main and sail the optimum angle downwind.  You will be heating up before the spin trimmer has a chance to say "heat it up" etc.  This is the #1 reason why I converted back to center bridle after trying aft bridle.  I have much better "feel" downwind and I like being that little bit faster downwind.
It also gives you much more "power" in the pump when you catch a wave, and I am getting on the plane a 1/2 boat length earlier .

2. The helm can grab the sheets and pull the boom across for a faster gybe.

The third advantage as Peter points out is that the center bridle is something to grab hold of during roll tacks and roll gybes to help pull yourself across the boat. The Viper is very wide for the helm and I like that additional hand hold to help me climb the slippery wall of the deck.

The disadvantage of the aft bridle (not to be confused with aft sheet) is that you dont have #1 and #2 above and there is also a higher risk of getting the tiller tangled up with the additional lines in the back of the boat.

The only advantage of the aft bridle (but it is a big one) is that it allows significantly more leverage on leech tension  (you are moving additional purchase towards the end of the boom wich is a lever arm).  This is an advantage in big breeze.

Originally, the Viper was designed entirely center sheeted and center bridle which was probably the easiest combination for the sailors.
From the inception of the class we also allowed center bridle and aft sheet which gave the mainsheet more sheeting power and was not noticeably harder to use.
More recently we passed a rule amendment to allow aft sheeting AND aft bridle.  IMO, this was a tricky one because it provides a distinct advantage upwind in big breeze by providing additional purchase/leverage but it gives the boat a disadvantage downwind and as a personal opinion make it harder and less enjoyable to sail.  I get around this by switching between the setups in different wind conditions but honestly, I have never thought of this as an ideal set of mainsheet rules.

If it were me I would level the playing field either by:
1. Disallowing the aft bridle so that all boats have the same purchase/leverage upwind. What does it matter , as long as we are all the same?
2. Or if we feel the main sheet needs additional purchase, allowing center bridle boats an additional purchase.....so that they are at least on level playing field upwind as the aft bridle

It would seem a fair bargain, if the aft bridle can mitigate their disadvantage by moving the purchase outboard and at the same time allow the center bridle to mitigate their disadvantage by getting additional purchase, we would have a more level playing field between the two set ups.