Jib Trim

[Don Guillette]

I’ve been searching the various forums for a sail trim subject that would be of interest to beginners and intermediate sailors but have not been able to find one – if this was the maintenance forum I’d have a lot of material!!

Fortunately, today a subject came in my mail. The sailor has a masthead rig and is having difficulty trimming his jib when sailing upwind.

First of all, trying to explain sail trim by phone or email is like trying to explain how to be a carpenter or how to play a musical instrument using the same means but I think guys like RichH, Stu J, Joe from San Diego, Jackdaw, Scott TBird and some others are pretty good at it.

The sailor indicated he feels his jib shape is OK as soon as he leaves the dock but as condition change his problems start – no kidding!! First, I asked what jib sail trim controls he uses – he said the jib sheet. He did not mention his fairleads!! We then had a discussion on the importance of fairlead adjustment and what the fairleads are actually adjusting.

As the wind increases I told him where to move the fairlead. What did I tell him and why? As the wind decreases I told him where to move the fairleads. What did I tell him and why?

 

[victorhoisington]

Don,

I've been sailing for a while, and do play with the fairleads a fair bit. However, I'm never sure what I'm doing is really working. That being said, here goes my take on the situation

Wind Increasing = Move Fairlead back, improves shape of lower sail to provide lift while allowing the top to twist off and dump wind at the top, thus reducing heeling affect

Wind Decreasing = Move fairlead forward, Keep shape on lower part of the sail and also reducing twist at the top to increase power and lift

Not sure if I have this right and don't get enough time on the water in all conditions to prove it to myself.

One thing I have found is that often (and I'm certainly guilty of this), I trim to tight and try to point too high, Falling off just a little and loosening the sheet just a little, provides better shape and more power.

I'm looking forward to what others have to say,

Victor

 

[BayMan]

Don,

I've been sailing for a while, and do play with the fairleads a fair bit. However, I'm never sure what I'm doing is really working. That being said, here goes my take on the situation

Wind Increasing = Move Fairlead back, improves shape of lower sail to provide lift while allowing the top to twist off and dump wind at the top, thus reducing heeling affect

Wind Decreasing = Move fairlead forward, Keep shape on lower part of the sail and also reducing twist at the top to increase power and lift

Not sure if I have this right and don't get enough time on the water in all conditions to prove it to myself.

One thing I have found is that often (and I'm certainly guilty of this), I trim to tight and try to point too high, Falling off just a little and loosening the sheet just a little, provides better shape and more power.

I'm looking forward to what others have to say,

Victor

What he said.

 

[Joe]

If you have a proper set of tell tales on your headsail the you can use the appropriate controls effectively. A bonus is a couple of draft stripes on the sail.

My memory aid for jib car placement is "bottom back"... which means if the lower tales break first when you luff the boat up... then lower part of the sail is too full and you need to move the car back to move tension from the leech to the foot. The goal is to get all the tales to break evenly.... this means the sail's "twist" is aligned with the wind's "shear".

Other trim considerations are halyard tension, backstay adjustment and barber hauling.

 

[Stu Jackson]

Garhauer makes a wonderful moveable car system.

If you're serious about this, buy two.

One for each side.

 

[Joe]

You can also move the lead car while under tension (without tacking over) by having a second car/block on the track to transfer the load while you move the lead block.

If you have an inside track... you can set it's lead block parallel to outside and run second sheet to clew... this will allow you to adjust sail to any sheet angle between the two tracks.

 

[CCHer]

Garhauer system I put on my boat. No excuse for bad sheet lead position!

 

[Don Guillette]

Joe brought up inside & outside tracks, which I had also mentioned to the lister that started this thread -- he only had outside tracks but assume he had both -- what is the purpose of both tracks and when would you use them? If you're a newbie jump in and take a stab at this question.

On the Garhauer adjustable system: if you own a masthead rig where the jib is the engine you should investigate this system. It was the first mod I added!! If you buy the system be sure to read and adhere to the instructions on the car -- DON"T REMOVE THE CAR FROM THE SHIPPING TRACK UNTIL YOUR READY TO SLIDE IT ONTO YOUR TRACK. My dock neighbor bought the system and I told him I'd install it for him but he wanted to do it himself. The next thing I heard was ball bearings hitting his deck and numerous water splashes as they hit the water. I asked him what happened and he said the car fell off the shipping track by itself -- yeah, sure it did!!

 

[Jackdaw]

Ah. adjustable headsail fairleads.

To me, tied for 1st as the most important sail shape control on the boat. With the traveler. If they are not remotely adjustable under tension, its the same as having a pin-stop traveler. Still adjustable, but a PITA.

If you add them, make sure you have enough purchase (3:1 or 4:1). Moving the car forward in a breeze is very loaded. Coming backwards is easy.

 

[Kings Gambit]

Without consulting Sail Power, or another sail trim encyclopedia for this reply, I typically position the sheet leads all the way aft when close-hauled in strong air; and position them forward in lighter air or when sailing lower. They are part of a continuously adjustable track system from Rutgersen. [Good luck finding that (Swedish) brand here in the States.] You can move the sheet leads under load, but if going forward I have to use the winch if there is much pressure on the sail.

From what I see the position of the jib fair lead controls the depth (bagginess) of the jib. If more forward the jib is more baggy; so in light air I tend to move them forward while also watching the break of the tell tells all the way up. I also move them forward when bearing off to lower points of sail, such as a beam reach. Sometimes there's too much twist at the head (it's not drawing at all) when doing this, so I have to haul down on the clew to tighten the leech. I do this with with a separate line through the clew to a snatch block at the mid-ship pad eye, led to the mid-ship cleat. [I think this is a "barber hauler."] In stronger wind, they come back to flatten the jib more so the boat can drive up wind w/ less healing force.

 

[Don Guillette]

On a boat with outboard tracks, I think a barberhauler is an important tool. On a race in Long Beach harbor I was on a boat that was always in the back of the pack. He asked me to come with him to see if he could improve his position. I don't know why he asked me as he refused to follow my suggestions. On a up wind leg I asked if I could use a barberhauler. He didn't want to. I told him what did he had to lose. We picked off 3 or 4 boats!! We lost the advantage at the next turn but that was OK, the guy became a believer.

The origin of the term "barberhauler" comes from the Barber brothers, who developed the technique sailing against Dennis Conner in San Diego. They're now dentist in San Diego. Joe from San Diego already knows all about this history lesson. In fact, he probably knows the Barber brothers!!

A barberhauler is easy to set up. I use a length of rope that I attache to the sheet using a sliding knot like Boy Scouts use to rig their tent lines. I always carry one in my sail bag on any boats I go on. I also always carry a set of telltales because most boats don't have them. How they trim their sails without them is beyond me -- I can't and I know what I'm looking for.

 

[Jackdaw]

Good points Don. Haulers (BarberHaulers, InHauler, OutHaulers, twings, etc) are key to effective sail shape. How you use them is primarily a function of your track position.

I often try and explain sail trim and adjustment like this... your adjustments should allow you to easily position the CLEW of the sail in three dimensional space. Almost all sail shape results from this. You have to be able to go in each direction on all axis's on both sails to do this. If you cannot you have one hand tied behind your back.

On the headsail, sheet, adjustable car, and haulers do this.

On the mainsail, sheet, traveler, and outhaul do this.

 

[Jackdaw]

One other note...

The original Barber hauler was design to OUT-haul, not IN-haul. Like most race boats, the Lightning (what the Barbers sailed) had very inboard sheeting with a non-overlapping jib. Great for W/L racing. But in high winds, or while reaching, it was hard to get good sail shape with the fixed lead position. So (in accordance with class rules), the Barbers rigged a system to pull the jib sheets outward. It's a great idea for reaching.

In pure windward mode, our inboard track gives a very tight sheeting angle.

But on reaching, this position would pull the clew end of the sail inboard, wrecking its shape. So hauling it out, or using a 'reaching sheet', gives much better shape. In this pic switching the outboard sheeting gained us .4 knots, from 6.3 to 6.7. Nice.

A reaching sheet would run from the clew to a block on the rail, and back to a winch. Easy and effective to try.

 

[Joe]

The in vs out "barberhauler" came up a few years back... I've seen rigs set up both ways... and they are called barber haulers either way.... the essence being that it gives the headsail trimmer an athwartship control which changes the sheeting angle...without reaving a new sheet through a new block on a different track.

Don's comment is that they can be quickly/temporarily rigged with a little creativity. On my older Nacra beach cat the barber hauler was permanently installed. It pulled the sail outboard to open the slot between jib and main. So for a long time, I only thought they pulled out.. until I saw an article by a well respected racing writer discussing the subject and his examples showed the barber hauler as an IN haul. So.... it depends on the boat.

My boat has a genoa track on the rail. I have a short inside track on the coaming that will accommodate the 135 genoa... but it's kind of a pain, so I use the lead block to rig a barber hauler to pull the clew inboard. For the 110 jib the clew lines up with the cabin top winch so I simply clip a line to the sheet to pull the clew inboard. I never attach the barber haul to the clew, it clips to the sheet..... just in case there's an emergency, releasing the sheet will still let the sail fly.

 

[Don Guillette]

My C30 had a track on the cabin top that I would have loved to use. I spent many hours and went through a lot of "tinny's" (Aussie for beer) trying to figure a way to make it work. Garhauer made a snatch block that flipped open with one hand that I thought would be the answer but the safety lines were always in the way. My "rope", which I ran to the lazy winch, looked Mickey Mouse but it did the trick. If I became over powered, which happened a few times, I just spun it off the winch and let the outside track take over.

 

[RichH]

This may be pretty 'advanced' but I'll post it anyway, hopefully to better the understanding of the 'sail interaction' between jib and mainsail.

One of the important aspects of 'jib trim' is usually always omitted by 'sailing schools' - adjusting the 'slot' or the distance between the jib's leech and the mainsail/mast ... how close the jib should be to the mainsheet versus the windspeed.
A racer will typically have the undersides of his/her spreaders incrementally marked (a series of taped lines on the underside) to visually show the relative 'tightness' and position of the jib's leech and) to measure that 'slot open distance'. When the boat seems sluggish many times just allowing the jib leech and/or jib clew position to 'fall off' an inch or two to leeward (or pulled in to windward) will make a LOT of difference.

So, once you begin to 'master' all the other trimming, etc. techniques ..... A simple/basic approach to 'set the slot' would be: when the wind is 'light' the jib should be closer to the mainsail and when the wind is 'strong' the jib should be out and away from the main. Get it wrong with the combo of sail interaction, the wrong slot distance based on the current conditions and the combined efficiency of the two sails 'acting as one lifting surface' falls of rapidly.

So, how does one adjust this slot distance?
Answer: double fairlead tracks (advanced trimming/racing), barberhaulers** (also advanced trim/racing), or most simply for 'newbies' - easing or tightening up on the jib sheets.

Method: When on a hard beat to windward, and all the tell tales are streaming correctly - streaming straight back with maybe the windward tales occasionally twirling softly:

... the clew comes in/inboard until the leeside middle / midcord tell tale(s) on the mainsail (the one closest to the leech of the jib) begins to 'twirl', then as you watch the 'spreader marks' .... (for 'newbies') - ease or increase tension in the jibsheet so that the jib CLEW moves in or out to get the best speed out of the boat for the current wind/wave conditions AND that middle tell tale on the leeside of the mainsail again streams aft. All done while watching your boat speed go to its highest value .
Maximum boat speed will occur when the slot open distance is 'perfect'. When this happens youll also see when looking from the cockpit, that the curve of the leech of the mainsail will somewhat closely 'match' the curve of the leech of the mainsail - called 'timing of leeches'. The optimum slot open distance will change with changes in wind speed and boat velocity.
With a perfectly 'timed' and correctly set 'slot distance' you'll notice that the air flow IN the slot will be at a MINIMUM; that's right, the air will be SLOWED DOWN through the 'slot' when that slot distance is set correctly. Why this 'works' is that with the air in the slot and on the 'windward' sides now being slower, the air will begin to 'back up' on the windward side and MORE air will 'get out of the way' of the oncoming boat/sails way out in front of the oncoming boat/sails and will 'shift' towards the leeward side and appear to be 'sped up' in doing so - called 'upwash'.

If you want to 'try' with more advanced trim:
Double fairlead tracks for jibs ... OR
**Barberhaulers: a single set of additional 'lines' that run from the cockpit, etc. to cabin top (snatch block, etc.) TO the clew ... the more the barberhauler runs level with the horizon and at 90° from the boats centerline to the clew (or the jibsheet near the clew), the better. 'Light' slippery lines are usually used.
Adjusting Jib sheet tension to get that best 'slot open distance' will work for 'newbies' and some 'oldies' too.

Some 'super advanced boats' simply attach their jibsheets to crossdeck-travellers!!! (see attached pics).

 

[Scott T-Bird]

1 question, 1 comment ... doesn't the jib size and the cut of the jib shape how you might answer the question? Also, I find the backstay adjustment on my masthead rig is the most important control for the head sail.

My experience is based on the struggles of shaping a large 150 genny as the wind strengthens. My biggest problem is the fluttering leech when I'm pointing up wind and the increasing draft. I find that ANY tension on the leech cord causes the sail to hook, so I find it useless. When the wind strengthens and the leech begins to flutter, I leave the fairlead forward to keep the leach tighter and I haul on the backstay to reduce the draft and keep draft forward. I have that photo that Rich posted etched in my mind to remind me what a bad idea it is to overdue the twist as the wind strengthens ... with the sail way twisted off and a huge belly in the draft, that is the last shape I want in a strong blow.

I find that reducing the draft with the backstay has more effect than playing with twist with the fairlead. With the sail flattened, it seems that I don't have to induce much twist to keep the telltales streaming, so my tendency is to keep fairleads more forward than one might think ... mainly to keep the fluttering under control.

Now, about the size and cut ... my fairleads are on the rail, and when the 150 is close-hauled, the leech is within inches of the spreaders. If I were to use an in-haul, the spreaders would interfere. This leads me to believe that a 150 isn't really cut for upwind sailing and that sail shape is better managed with a smaller headsail. I have made note of that when I want to shop for the replacement.

 

[RichH]

Scott - two things may be causing your leech line to be 'inoperative'
1. the leech of your 150% probably has become stretched-out ... happens as a long term result of using too much jib sheet tension - gorillas on the jib sheet winches.
2. the sail probably was cut/designed with insufficient 'hollow' cut into the leech shape.

Such a sail with constantly vibrating leech where the leech line cant adequately control the flutter but where application of the leech line cause the 'edge' to 'cup up' can be corrected - by recutting and resewing the panels in their leech area ... or by simply cutting 'more leech hollow' (a deeper smooth curve from clew to head) into the sail.

For me Id only use a 150LP when Im not using a spinnaker. The 150 is more or less a compromise for those who dont use spinnakers for downwind. For 'pointing' the 150 has poor aspect ratio - the ratio of height to foot. The higher the aspect ratio the better the pointing ability. Thats why one rarely sees a BIG genoa on serious racing boats, especially those who race primarily on windward-leeward courses - the preference seems to be in the 120% (130% max.) range. A 150 'may' have an advantage on the old fashioned (boring) 'triangular' race courses that had '2 reaching legs' for every windward leg ... and even on those courses a spinn will be much better for reaching.
There may be a free-flying spinnaker / furler in your future ???? thats the direction I see where recreational sailing is going.

best regards

 

[simplynick912]

rookie question on this

1 question, 1 comment ... doesn't the jib size and the cut of the jib shape how you might answer the question? Also, I find the backstay adjustment on my masthead rig is the most important control for the head sail.

My experience is based on the struggles of shaping a large 150 genny as the wind strengthens. My biggest problem is the fluttering leech when I'm pointing up wind and the increasing draft. I find that ANY tension on the leech cord causes the sail to hook, so I find it useless. When the wind strengthens and the leech begins to flutter, I leave the fairlead forward to keep the leach tighter and I haul on the backstay to reduce the draft and keep draft forward. I have that photo that Rich posted etched in my mind to remind me what a bad idea it is to overdue the twist as the wind strengthens ... with the sail way twisted off and a huge belly in the draft, that is the last shape I want in a strong blow.

I find that reducing the draft with the backstay has more effect than playing with twist with the fairlead. With the sail flattened, it seems that I don't have to induce much twist to keep the telltales streaming, so my tendency is to keep fairleads more forward than one might think ... mainly to keep the fluttering under control.

Now, about the size and cut ... my fairleads are on the rail, and when the 150 is close-hauled, the leech is within inches of the spreaders. If I were to use an in-haul, the spreaders would interfere. This leads me to believe that a 150 isn't really cut for upwind sailing and that sail shape is better managed with a smaller headsail. I have made note of that when I want to shop for the replacement.

Thanks for all this info!! a lot to absorb for sure !! i recently bought an 84 cat 38 that has a 150, two tracks, and having a hell of a time sorting it all out. she's fast but the jib is a handful. Rookie question for starters: do your sheets come inboard over the lifelines, or through. if through, where?

 

[dmc]

Don,....

I've been using barber hauls for the last two seasons. My old Hunter is a great "lake" boat but has a perforated rail. That's real handy, you can mount a block anywhere, but you can't move them under load. The barber haul is with out a doubt the cheapest and one of the most effective piece of rigging on the boat. A length of line, a Garhauer block and an inch and a half SS ring on the sheet. The effects on the head sail are visible. The barber hauls allows better trim upwind and I don't use them downwind. It does allow me to set the "primary" sheet block farther aft and deflecting the sheet almost mimics a movable sheet block. Making a barber hauler just to play with may help decide where to install that new movable jib car track.

dmc