Flatten Your Mainsail Foot with an Outhaul

As I mentioned at the start of the Boom vang solution post, my mainsail is a bit stretched out. The boom vang in that post was the first step at getting control over all three sides of the sail—the leech tension. Step two in this post is a trimmable outhaul for control over the foot tension. The last step is a boom downhaul for tension on the luff, which will be a future post.

Most old C-22s came from the factory with a simple loop of line between the mainsail clew and an eye strap at the end of the boom similar to the picture below. It holds the sail in place but that’s about all. You can’t easily trim it while sailing. If it’s loose enough to make connecting the clew easy, then it isn’t tight enough for moderate to heavy winds. If you take the time to cinch it up tight, you’ll have to untie it to take the sail off if you trailer like we do. By then, the knot could be hard to loosen.

BEFORE - Easy or tight, but not both
BEFORE – Easy or tight, but not both

The solution is a trimmable outhaul. A certain Catalina parts dealership  offers a four part kit. The problem I have with it is that it doesn’t use a becket to anchor the working end of the line. Instead, their kit anchors the line at another eye strap on the boom. Fair enough, unless you have other rigging that needs to be mounted there. My design for boom rigging needed that location for the topping lift cheek block.

Taking my cue from Chip Ford and starting with a smoking deal on a pair of Harken blocks on eBay, I put together a five part outhaul that anchors the line at a becket on the forward block.

My outhaul consists of:

  • Harken 085 double block with Becket
  • Harken 086 triple block
  • Fixed eye snap shackle
  • (2) Harken 072 3/16″ shackles
  • 5′ x 1/4″ New England Ropes Sta Set or equivalent. This line is white with blue flecks in keeping with the systematic color scheme that I’ll describe in a future post. Notice in the picture below that I spliced an eye in the end of the line where it attaches to the becket. You could also use a bowline knot there but I prefer the neatness of spliced eyes, particularly here at the end of the boom where four lines are attached (main sheet not shown).
AFTER - Easy to attach and trimmable
AFTER – Easy to attach and trimmable

Size does matter

The challenge in this setup is to get the overall length of the outhaul as short as possible. There’s only about 10″ from the clew to the eye strap at the end of the boom. If the combination of hardware is too long when you tighten the outhaul, the blocks will meet in the middle before putting enough tension on the foot of the mainsail. To solve the challenge, I used the shortest shackles I could find and I also shortened the becket on the double block. The unmodified becket had two holes in it. I cut the becket off at the farthest holes, filed the ends smooth, and remounted the becket pin and spacer in the first hole set. This combination leaves just enough space to get good tension on the mainsail foot. Another option is to anchor the working end of the line on one of the sheaves of the block itself, like Chip Ford did but that will result in a four-part system.

To make it easy to use, the working end of the rig has a snap shackle for hooking to the clew. The standing end of the line is adjustable at a fairlead cleat forward on the port side of the boom. The fairlead keeps the line captured at the boom if it gets out of hand. A foot of slack on the end makes the rig easy to trim while under sail and to loosen while removing the sail when its time to head home.

The two lines that you see hanging down from the aft end of the boom in these pictures are the working ends of the topping lift and jiffy reefing lines held out of the way for simplicity. I describe them both in other posts. To see how all four systems (including the main sheet) fit on the boom, see the pictures below.

Boom end with all rigging shown
Boom end with all rigging shown
All four lines sharing the end of the boom
All four lines sharing the end of the boom

Reliability update

It’s been a couple of years since I rigged this outhaul and it has worked well, if maybe too well. A five-part tackle is a bit of overkill for an outhaul. It doesn’t need that much mechanical advantage. Also, the clew grommet of my new mainsail is too thick for the snap shackle to fit through. If I switched to a larger snap shackle, it would also be longer and make the whole setup too long to fit between the clew and the end of the boom. So I decided to downsize the outhaul to the 2:1 setup shown below.

Simpler 2:1 outhaul is also shorter
Simpler 2:1 outhaul is also shorter

This system requires only one block with a becket and the line runs through the clew grommet itself. The line isn’t as easy to pull as before but it’s still easy enough.

I also moved the jiffy reefing hardware forward as a separate modification, which you can read about in Single Line Jiffy Reefing Made Easy.

The Bottom Line

Suggested price: $135.69
$tingy Sailor cost: $49.99
Savings: $85.70


8 Comments Add yours

  1. Dave Larson says:

    Have been reading your posts with great interest since purchasing a ’74 in February. Planning to do the topping lift and outhaul as soon as I repair the forestay reinforcement. I’m curious about your costs. For this project, the cost of the 085 and 086 blocks alone is in the $90+ range from the two suppliers I checked. Can you recommend a less-expensive source for hardware? Thanks,

  2. kbilling says:

    Hi, Dave

    Yep, they’re pricey little buggers! The main reason that I used that size of blocks was because I got the pair of them on eBay for around $25, so it was a no-brainer. If that had not been the case, I would have used something like the Harken micro blocks 227 and 228 at around half the cost. Those are also the size that Catalina Direct uses in their kit. Another benefit would be that their combined length is even a little shorter, which might make the difference with a long-footed mainsail.

    When I need to buy parts at retail instead of eBay, I like defender.com. They don’t offer free shipping but their prices are among the lowest for most things and they have a great selection, which means I can usually get several things on the same order to spread the cost out and still be less than most other retailers.

    Good luck with your improvement projects. Hope to see you here some more!

  3. Dave Larson says:

    Thanks, $tingy. I figured you had to have done something like that. Just started the topping lift project today: bought a piece of 7/64″ Amsteel and put an Brummel eye in one end and another Brummel eye with a thimble in the other. Will have to wait till the next time I drop the mast to install it. I think the necessary hardware is already on the boom. Was thinking about attaching it to the main halyard for a quick check of the concept, either with or without the mainsail. I know the lead won’t be quite the same as attaching it alongside the backstay on the masthead truck, but it should be close.

    1. kbilling says:

      Glad to hear you’re going for it! I think you’ll like how handy it is to just reach up and hoist the boom up whenever you need to.

      Must be kinda tricky splicing line that small. I’ve only done as small as 1/4″ so far and that was tough enough. Did you make a core to core splice?

      1. Dave Larson says:

        Had to look up core-to-core splice, but no, that’s not the technique I used. The Amsteel line is single-layer, not cored. I used these instructions (http://www.l-36.com/brummel2.php and http://www.colligomarine.com/docs/misc/splicing_instructions_for_web_rev_1_2.pdf) modified to account for the fact that the smaller line is 8-strand, not 12. {I can’t find any sites that call the 7/64th rope as 8-strand, but that’s what I have.
        It wasn’t hard to work with at all.

      2. kbilling says:

        Interesting splice and it looks faster to make. I might try that on the lazy jacks I’m making. They don’t need the full strength of a conventional eye splice and I don’t want to have to make 8 of them!

  4. The most no-nonsense, comprehensive forum I have found for our boats. Thanks. 1987 Cat. 22 SK #14218

    1. kbilling says:

      Thanks for your comment, John. We could all gain from less nonsense and more common sense.

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