Flattening the Main

[mike]

I've read that a flatter mainsail yields better upwind performance... our main usually seems way too full, and I'd like to find a way to flatten it out some when needed. Supposedly the adjustable backstay I installed yesterday helps flatten the upper parts of the sail, and a book I'm reading now suggests increasing outhaul tension to flatten out the lower part. Because my outhaul is simply a line cleated near the end of the boom, it's not really practical to adjust the outhaul (at least not while sailing), so I'm wondering whether some sort of improved outhaul control would be beneficial.

Or, is the stock 26x main simply too baggy (in other words, too much for any amount of adjustment to flatten)?

--Mike

[Frank C]

I'm convinced that you really need to make several mods to get reasonable sailing performance. When winds get over 15 knots the boat can be the most fun, but then it absolutely requires controls for flattening the main. In priority, I think the 26X requires:

• 1. reduced mast rake to reduce weather helm in higher winds
  2. a high-purchase vang to help flatten the main (alternatively, a traveler),
  3. a good outhaul to help shaping the main,
  4. and maybe an adjustable backstay.

I came across a digi-pic of my outhaul on an old disk, so I uploaded it to Heath's mods page. It works fine but someday, I'll reduce purchase to 3:1 - plenty. You can read details at the mods page for Outhaul 4:1.

I used the sailhook because I wanted to use the same rig, by simply extending the line, for the reefing cringle - it works, but it's not yet perfected for speedy reefing underway.

[mike]

Frank,

Thanks for the info. I took out much of the mast rake Friday, and I do think it helped (that, and the adjustable backstay). I'm definitely going to do an outhaul next, and am debating on whether or not to install a traveller, which seems fairly expensive (especially the risers to get the track up above the sliding hatch). In addition to the increased control, it sure would be nice to get the mainsheet out of the cockpit. Though, on the other hand, there would be an additional obstruction on the cabin top. So, I may just go for an improved vang. I saw a diagram in the Harken catalog that lets you fairly easily double the purchase of an existing vang.

On your outhaul, I assume you don't have the line led to the mast and back to the cockpit... is having the control on the boom a hinderance, or is it ok?

--Mike

[TonyHouk]

Hey Frank,
A question for you. Is that a picture of it being three to one? I only see three lines doing the pulling with the forth line going back to cleat. That would make it a 3:1 system and not a 4:1. Please correct me if I am wrong... Happy sails, Tony

[Frank C]

Tony,
You're probably right ... I never get it right on how many of the lines are working. I guess 3 blocks mean three working lines, while the cleated line is just changing direction?? ...

Mike,
No, I did not bother to run this line to the mast and back across the deck. I figured I'd do that eventually, but I don't find it much of a hassle to work it on the boom. The real problem - managing the excess line is a hassle. IMO, the correct answer would be adding a take-up tackle inside the boom to handle the surplus line ... alas, the Mac boom is so tiny and thin, I'd be loathe to cut it for exit blocks.

RE vang, I bought the Garhauer 12:1 from my dealer with the new boat, and I've never regretted that purchase. The dealer wanted half that much for the standard vang.

[bscott]

Yes the main is too baggy---you can have it recut flatter at a sail loft.
Ease the main and jib halyards for down wind and harden them tight for up wind; reaching, keep it in the middle. I mark my halyards with an indelible pen for each point of sail.

If you rig is tuned forward, the adjustable backstay will bend the top of the mast back while forcing the middle of the mast above the gooseneck forward. This will bring the draft of the main forward reducing the fullness of the draft which will reduce weatherhelm. This is extremely important for fractional rigged boats. Harden up the jib halyard which will effectively shorten the forestay and flatten the jib

The vang will help a little for up wind work but only for the lower mast at gooseneck level. Harden up the vang for up wind, ease off for down wind.

The greatest aid in up wind performance is the addition of a mid boom traveler.

[Frank C]

Yes the main is too baggy--- . . . The vang will help a little for up wind work but only for the lower mast at gooseneck level. Harden up the vang for up wind, ease off for down wind.

The greatest aid in up wind performance is the addition of a mid boom traveler.

Actually, the Garhauer vang helps "more than a little" when going upwind in heavy air. Remember these factors . . .

• * it's actually too long for the Mac, so it rides about 60deg off the mast, only 30deg off the boom.
  * this places the vang's downforce well aft compared to a normal vang
  * it's 12:1, so you can add quite a lot of downforce.
  * I actually noticed a ~2" arc pulled down on my boom by the vang
  * I later found the gooseneck casting fractured - perhaps related.

Upshot of heavy vang (with good outhaul) is a remarkably flat, factory mainsail, though at obvious risk to the boom. My few days where I got everything working right, I've seen long upwind tacks at GPS speed of 7+ knots, just kissing 8 knots, wnds steady @ 18-20kn. That's with reefed main and full, unfurled jib (can't really adjust the jib halyard on a furling jib).

Sure, I'd rather use a traveler but it's tough to add on a Mac without somehow impairing access. (Cabin-top means a very expensive bridged traveler, and blocking the deck passage). Ignoring space & access considerations, ideal placement could easily be just in front of the pedestal at 3/4 boom, or just aft of the companionway, bridging the coamings. Our booms are too light and flexible to really manage the sail at the cabin-top, mid-boom position, IMO. Of course, there's nothing wrong with getting a new boom to go with that new traveler. However, my first attempt at a traveler will probably be across the forward cockpit coamings. This will place the bail about 12 or 15 inches aft of mid-boom.

[mike]

Sure, I'd rather use a traveler but it's tough to add on a Mac without somehow impairing access. (Cabin-top means a very expensive bridged traveler, and blocking the deck passage).

While I'm not thrilled with having the obstruction up on the deck, it would be nice to get the mainsheet out of the cockpit (an accidental jibe almost took my wife's head off during one of our first times out). But the astronomical cost of those track risers is primarily what has me turned off to the idea.

Is there any more reasonably price option than the Harken $500+ risers?

--Mike

[Chip Hindes]

* it's actually too long for the Mac, so it rides about 60deg off the mast, only 30deg off the boom.
* this places the vang's downforce well aft compared to a normal vang

If the lower attachment point on the mast does not move, moving the boom attachment point of the vang aft actually decreases the downforce for a given vang tension. Put another way, you need increased vang tension for a given downforce. This in turn increases the forces on the attachment points at the boom and mast, and at the gooseneck. Without doing the actual numbers, my guess is a 12:1 on the vang is capable of permanently bending the boom, and you've already proven it's capable of breaking the gooseneck casting.

[Moe]

So does this mean a Boomkicker with a standard vang would do the same jobs (lift in light wind, lower in heavy wind), with less stress on the boom?

What about ease of use, i.e. connecting/disconnecting during setup/teardown? Which (rigid vang vs boomkicker) has the advantage there?

--
Moe

[Duane Dunn, Allegro]

I'm very happy with my boomkicker. It fits right inside the factory vang without any modifications. It supports and lifts the boom easily, the vang provides all the down adjustments needed.

Installation is a snap. You just screw the boom fitting on and slide the mast fitting in the sail track.

Once installed taking the boomkicker off and on is 5 seconds tops. I changed the lower pin to a quick pin from the ring ding one. You just slack the vang, lift the boom and the upper end slides out of the slot in the fitting. (there is no pin to remove at the top). Pull out the quick pin at the bottom and you are done.

You can't bend the boom as much with the 4:1 standard vang as you can with the 12:1 rigid one.

[mike]

Yes, the Boomkicker was surprisingly easy to install. I'm pleased with it, but I have a very hard time pulling the vang tighter when the main is sheeted out... I have to physically pull the boom down as I try to tension the vang, or I guess I could point into the wind closer and use the mainsheet to assist getting the vang tighter.

As I mentioned before, the Harken catalog shows a simple way to change the 4:1 to an 8:1 by adding one block. I'll probably do this (being careful, of course, to not pull too enthusiastically so as to not bend the boom).

--Mike

[Chip Hindes]

I have to physically pull the boom down as I try to tension the vang

This is certainly not unique to the Boomkicker. On the "stock" vang, you can't get adequate vang tension just by pulling in the vang itself, and you can't physically pull the boom down enough to do any better because there's nothing to grab onto to pull it down. I've learned I must pull the boom down and in with the mainsheet, tension the vang and then ease the mainsheet to get the boom out where it belongs.

This works OK but the tension on the vang and its attachment points is incredibly high; if you release the vang without reversing the sequence, it takes a heck of a pull just to get it out of the cam cleat, and it lets go with a bang that reminds you not to have any of your fingers or other body parts in the wrong place when you do it.

My rough estimate, based on the near endboom location of the attachment and the more favorable angle, the mainsheet system has somewhere between a 6:1 and 8:1 advantage over the stock vang. Most of you know the vang and mainsheet are identical sets of 4:1 blocks.

[Duane Dunn, Allegro]

I assume you are talking about a cascading system like the one shown in this article.



Here's another linkwith lots of vang choices.

Looks like it could be easy to add but you would have to make sure that additional mast fitting can take quite a bit of load.

[Chip Hindes]

I assume you are talking about a cascading system like the one shown in this article.

I believe there is an error in the picture. The auxiliary block adds 2:1 and the pull force on the boom attachment point should be 800 lbs, not 200 lbs as shown. Otherwise, it's a waste of effort. You'd think Harken could get it right.