Bridle v Traveler?

[[3889]]

Can anyone explain the advantage, if any, of a traveler over a bridle for short handed crew who don't want to play the main?
In this thread
http://jeanneau.proboards.com/thread/3318/improving-standard-mainsheet-system-00
the bridle seems a much simpler, and cheaper, means to achieve the same end.

 

[jwilson]

Can anyone explain the advantage, if any, of a traveler over a bridle for short handed crew who don't want to play the main?
In this thread
http://jeanneau.proboards.com/thread/3318/improving-standard-mainsheet-system-00
the bridle seems a much simpler, and cheaper, means to achieve the same end.

The main difference is that a bridle stops you putting the traveler up to windward and easing the mainsheet when you want more twist in the main for light winds. Bridle is fine if you don't care about sailing to windward efficiently in all conditions. But sailing efficiently can make the difference between being silent and having an engine going. I don't race much these days but I do like to sail properly - ie fast.

 

[[3889]]

The main difference is that a bridle stops you putting the traveler up to windward and easing the mainsheet when you want more twist in the main for light winds. Bridle is fine if you don't care about sailing to windward efficiently in all conditions. But sailing efficiently can make the difference between being silent and having an engine going. I don't race much these days but I do like to sail properly - ie fast.

Not saying you're wrong but I don't follow this. The working leg of the bridle is attached at the same point as the traveler car when hauled to windward so isn't sheeting angle the same? Is twist not increased by easing the kicker, or applying topping lift in light airs?

 

[Bobc]

What quiddle says is right.

The idea of the bridle is that you can centre the boom without putting downward load on the leech. The only downside of this, is that it means that the only way you can add leech tension is with the kicker (whereas with a traveller you put it near the centre and grind the boom down with the mainsheet).

When my traveller finally gives up (which by the noises its making, won't be long now), I'll be fitting a bridle instead.

Ps. Use Vectran for a bridle, as it's strong, low-stretch, and you can adjust the length easily by making and adjustable soft eye in the boat end of it.

This is what you want (something like 8mm) http://www.englishbraids.com/leisure-marine/dinghy/dinghy-control-lines/dynamic-line-sk78-detail

 

[MikeBz]

The bridle does allow twist - it pulls the boom athwartships not down, except when you get to the final inch or two. Unless the sheet is ground in really tight the kicker/vang controls the twist. The bridle could have control lines to provide infinite adjustability, in which case the only 'advantage' a traveller has is that it can do the kicker/vang thing as well which would be an easier way to eliminate twist.

Many decades ago most racing dinghies were fitted with a traveller - now they almost all use a bridle arrangement to allow the boom to be centred without applying unwanted amounts of leech tension.

The point of my mod is that it is a huge, free, improvement to a poor standard system. It allows as much twist as you would ever want in light winds. A traveller (or adjustable bridle) would allow you to get the last 0.001% in all conditions but for cruising having 99.999% some of the time and 100% the rest of the time is good enough for me (and I've spent 40 years racing competitively).

 

[lw395]

Bridle sheeting has become the norm in dinghies, but on a yacht you will need a very serious kicker to get the same leach tension you get from traveller sheeting.
Many yacht rigs are not going to be strong enough, the vang loads the boom hugely and also pushes the mast forwards.

 

[MikeBz]

If you set the bridle length just a fraction short then the last 6" or so of mainsheet does apply leech tension - by this time the boom is almost on the centreline so you can control leech tension without the boom dropping away. What you can't do, which you can with a traveller, is dump the boom to leeward whilst maintaining leech tension but this is only really desirable on rig with a bendy mast and a lot of luff round cut into the sail (like a Finn!). Cruising yacht mains typically have very little roach and don't need huge amounts of leech tension, unlike the fat head fully battened mains on modern dinghies.

 

[Bobc]

Bridle sheeting has become the norm in dinghies, but on a yacht you will need a very serious kicker to get the same leach tension you get from traveller sheeting.
Many yacht rigs are not going to be strong enough, the vang loads the boom hugely and also pushes the mast forwards.

That all depends on how you set the lengths of the bridle ropes, and hence the height of the block. If you set it so that when it's block-to-block, your leech is right for upwind, then you're good to go. So what then happens is that mainsheet closes the leech during the final bit of sheeting-in. You can then control the leech tension without letting the boom out just by easing the mainsheet slightly, and your kicker is only used to control the leech when off the wind.

 

[Bobc]

What Beezer said (he said it better than me).

 

[jwilson]

Not saying you're wrong but I don't follow this. The working leg of the bridle is attached at the same point as the traveler car when hauled to windward so isn't sheeting angle the same? Is twist not increased by easing the kicker, or applying topping lift in light airs?

Not yet seen any normal bridle arrangement where you can actually have the boom on the windward side of centreline with sheets and kicker eased to really put lots of twist into the main. The one shown in the tiny photos at http://jeanneau.proboards.com/thread/3318/improving-standard-mainsheet-system-00 let you get the boom close to but never actually completely centred, and certainly not to windward. Better than the standard arrangement at http://www.yachtsnet.co.uk/archives/sun-odyssey-32/s610-deck.jpg though.

OK - it's getting a bit light-airs-racy, but on a nice day it's better to sail as fast as you can rather than run the engine.

 

[lw395]

But if you crack the sheet in a gust, the boom goes out instead of just twisting the top.
So you tend to have to dump more sheet to keep the boat from heeling.
With a traveller and 'normal' sheet you have 2d control.
With a bridle, that reduces to 1D unless you have freedom to get leach tension from the kicker.
In my dinghy, which has a hoop, the sheet is pulling from high up, broadly like a bridle.
Until it's quite windy, I can sail very effectively with very little kicker, but only on a beat.
Put us on a fetch where the sails are cracked off, it's very very slow and hard work without the kicker.

Above a certain wind, the kicker does nearly all the leach tension, and the sheet works more like a traveller on a big boat.

I would think a bridle might be fine if the lengths are exactly right for the conditions, on a true beat or well off the wind.
As you hint, many dinghies feel the need to adjust the bridle day to day.
It will vary depending on the rig of course.
Also, I'd consider whether the sheet blocks flailing around near the cockpit might be an issue? Enough people have been hurt by fine tune blocks, let alone having the main blocks lashing around on a couple of strings...

 

[Bobc]

Not yet seen any normal bridle arrangement where you can actually have the boom on the windward side of centreline with sheets and kicker eased to really put lots of twist into the main. The one shown in the tiny photos at http://jeanneau.proboards.com/thread/3318/improving-standard-mainsheet-system-00 let you get the boom close to but never actually completely centred, and certainly not to windward. Better than the standard arrangement at http://www.yachtsnet.co.uk/archives/sun-odyssey-32/s610-deck.jpg though.

OK - it's getting a bit light-airs-racy, but on a nice day it's better to sail as fast as you can rather than run the engine.

Why would you ever want the boom to windward of the centreline? (unless you wanted to go backwards)

 

[lw395]

Why would you ever want the boom to windward of the centreline? (unless you wanted to go backwards)

Because you want the mid section of the main sheeted in and the top twisted off, and you're prepared to compromise on the bottom bit being oversheeted to get that.
Some people seem to make it fast with massively overlapped rigs.
Even some dinghies pull the traveller up to windward. e.g. Merlin.

 

[Bobc]

Because you want the mid section of the main sheeted in and the top twisted off, and you're prepared to compromise on the bottom bit being oversheeted to get that.
Some people seem to make it fast with massively overlapped rigs.
Even some dinghies pull the traveller up to windward. e.g. Merlin.

Fancy a race?

 

[lw395]

Fancy a race?

I think you've got a quicker dinghy than me....
I also think the technology of main strops has been around a long time, there is good reason why it works on dinghies and not on all yachts.
I don't think they fit those fancy travellers to Admirals Cup yachts just because they like the Harken salesman....

 

[Bobc]

Just yankin your chain

 

[jonjo]

In the recent "luff in puff" thread very few knew what it referred to or could explain the benefit. Yet in this thread folks are talking about mainsail twist tuning that goes over my head metaphorically speaking.

I routinely luff in a puff and can feel the advantage gained but seem to be missing out on mainsail twist tuning. Could someone from a racing background comment the relative %1 gains to be made from the two techniques? I have an end of boom mainsheet traveler in the cockpit.

 

[mrming]

In the recent "luff in puff" thread very few knew what it referred to or could explain the benefit. Yet in this thread folks are talking about mainsail twist tuning that goes over my head metaphorically speaking.

I routinely luff in a puff and can feel the advantage gained but seem to be missing out on mainsail twist tuning. Could someone from a racing background comment the relative %1 gains to be made from the two techniques? I have an end of boom mainsheet traveler in the cockpit.

Here's what I do...

I use twist in light weather to make sure the trailing edge of the main is not stalled and the boat can accelerate. But I don't want the the boom down over the corner of the transom (unless it's really ghosting and I'm sailing cracked off a bit to keep speed up), so I raise the traveller past the centre line so that the boom is still on the centreline and the leech is loose (all leech telltales flying).

In medium airs I make sure the top leech telltale is being sucked back in about half / one third of the time. I'm now powered up and want to point so I don't want the top of the main falling away to leeward. In the gusts I play the traveller to keep the boat on it's toes without losing the drive from the leech.

Once it gets heavy the main may end up right down the bottom of the traveller and the boat is still over pressed. Now I play the sheet again. In this situation I usually come back up the traveller a bit (say 3/4 down) to keep the bottom of the mainsail driving while spilling wind out of the middle / top by inducing lots of twist in the gusts.

 

[MikeBz]

Not yet seen any normal bridle arrangement where you can actually have the boom on the windward side of centreline with sheets and kicker eased to really put lots of twist into the main. The one shown in the tiny photos at http://jeanneau.proboards.com/thread/3318/improving-standard-mainsheet-system-00 let you get the boom close to but never actually completely centred, and certainly not to windward. Better than the standard arrangement at http://www.yachtsnet.co.uk/archives/sun-odyssey-32/s610-deck.jpg though.

OK - it's getting a bit light-airs-racy, but on a nice day it's better to sail as fast as you can rather than run the engine.

It would be easy and pretty cheap to make the bridle adjustable with a 2:1 on each side lead back to the clutch bank on either side of the coachroof. That would allow you to centreline the boom and induce twist by hauling on the windward side of the bridle and releasing the leeward side, just as with a traveller. I'm not saying it's better than a traveller in all conditions, but as an aftermarket fit it's a LOT cheaper and simpler!

Those are my boat/pics/text on the Jeanneau site, I've sailed with it to windward in light airs and it allows as much or little twist as I need.

To allay someone else's fears, the blocks are quite a long way forward of the cockpit and cannot flail around far enough to reach anyone. If you're up on the coachroof then the booms is more of a hazard...

Oh, meant to add that a lot of racing yachts do pull the boom to windward of the centreline - it seems counter-intuitive but these boats are fully instrumented and will be sailing to the best 'numbers'. The AC72s had the aftmost element of their wing way to windward of the centreline. Maybe not appropriate for a 4-KSB though...

 

[dom]

Could someone from a racing background comment the relative %1 gains to be made from the two techniques? I have an end of boom mainsheet traveler in the cockpit.

Excellent practical advice from mrming. To explain the logic is a bit tricky as it’s tricky to just visualise 3-D things like twist. The first point is that it is not the leech that twists, but the entire sail – twist is basically the change in the angle of attack from the bottom to the top of the sail. Twist, however, can be most easily observed by looking at the leech.

Now we know that as a boat goes faster the apparent wind angle changes and heads the boat. This is why light boats sailing fast to windward never appear to be point very high to the true wind, perhaps 60 degrees. In reality they are sailing at c. 30 degrees to the apparent wind.

The corollary of this is that a puff of wind reduces the effect of boat speed on the apparent wind, meaning that it lifts the boat, which can in turn point higher as a result – that’s the logic behind “luff the puffs”.

The core principal here is that the speed of the true-wind affects the angle of the apparent-wind

Now to twist: we know the wind slows the closer it is to the water, due to friction. The above logic implies that the head of the sail will experience a wider apparent wind angle than the foot, purely due to wind blowing a bit faster up there.

The top of the sail should therefore be a bit more “open” than the foot, which is why we allow the sail to twist. (You will occasionally see the Coriolis Effect referenced here; these theories are rubbish and should be ignored).

It is not possible to give specific advice here re twist angle as so many dynamic factors exist, but the rule of thumb for max power is “to keep the top batten (back third of a fully battened system) parallel to the boom”. This should keep the top telltale flying between 50 and 80% of the time.

If you want to depower your sail it is best to dump your traveller first. Should you find yourself consistently overpowered: then tighten your cunningham, wind on some backstay and increase the twist of the mainsail.

Someone has previously pointed out that some boats sail well with the boom upwind. In general this only applies to masthead rigs flying a full sized genoa, but it can work in boats with very specific sail characteristics – ignore if you’re not racing