Mainsail Features: loosefoot versus attached foot

reef reefed main mainsail sailing

This post comes from Jamie, one in a series where he shares his knowledge as a tenured sailmaker. For more about Jamie’s experience in the field, see Sailmaker SAYS!. 

My friend just bought a new mainsail and the foot isn’t attached to the boom. Her sailmaker said it’s the way to go, but I’m not convinced? Forever the skeptic, but I understand your concern because sailmakers are easily confused. So it is a bad idea, thought so. Actually, her sailmaker is right. Oh…

Grey Matters
Foot: the bottom edge of a sail.Loosefoot: This refers to a mainsail with foot not attached to the boom. The tack and clew secure the lower sail in place, and the foot floats freely.

Attached foot: A mainsail with foot secured to the boom by slides, slugs, or boltrope.

 

An attached foot is another example of, “because it’s always been done that way” sailmaking. Back in the ancient times, before Dacron, sailcloth was wicked stretchy. A flat mainsail got deeper with increasing wind. By attaching the foot to a sturdy boom, the sail would grow too wicked baggy; but a loosefooted main, back in the day, could take on a balloon like shape.

Those were the dark ages of sailmaking. Whoa, I never knew… Dacron, known in the fashion world as Polyester, was invented by DuPont and heralded a new, modern era of moderately stretchy sails. Though a significant improvement, mainsail features didn’t change. Eventually though, a sailmaker somewhere built a loosefooted mainsail – meaning he probably forgot the foot slides and then upon realizing boasted of a clever new innovation! A sailmaker mistake, I didn’t think that was possible. No,no, you have us confused with riggers. They never make mistakes…

Hahahahahahahahahahahahahahahahahahahaha! Sorry, just a little industry humor.

Anyway, it turns out that a loosefoot has advantages. For one, it’s a little easier to bend the mainsail on if you have only to attach tack and clew, and not a bunch of foot hardware. More importantly, sail shape low in the sail is better with a loosefoot. When the foot is attached, sail depth gets pulled out; no lift generating foil shape. Ever see a flat airplane wing? Ah, no. Well, a two dimensional sail doesn’t work either. Loosefooted, sail shape retains good wing like shape along the foot. We used to build attached foot mains with a lens shaped panel to solve this, but it still wasn’t perfect and added time and cost to a sail. Something sailmakers are good at!

Yeah, yeah, but I’m telling you that loosefoot has no foot hardware, which means less cost. And the simplicity of it has advantages. You see, some sailmakers use shackles to attach foot hardware. They make noise banging against the boom; and are either plastic, which will rot in the sun, or metal, which will scratch the boom.

Wow, a loosefooted main really makes sense. What about mizzens? Yeah, same. Wait, hold on. Doesn’t the attached sail, main or mizzen, give strength to the boom? No.

But the…. No.

But I read on the intern… No! Look, a boom is aluminum or wood or even carbon fiber for the lucky ones. It’s rigid! Well, wood is a bit bendy, but generally very stiff. A sail has stretch. And even if it didn’t, let’s say you have a carbon fiber mainsail, lucky bastard, it has shape. You remember the part about airplane wing right? Yes, yes. Sail shape, depth, means sailcloth isn’t taught enough to counter forces on a boom, such as mid boom sheeting. And it probably made of stretchy Dacron. Take a pencil and tape plastic to it like a boom and sail. Now make the plastic a little baggy and then see if it prevents the pencil from breaking when you apply force to the middle, with ends secured. Snap.

Is there any scenario where an attached foot is the way to go? Yes, if the sailcloth is Egyptian cotton. Oh, and if you want to take one of those photos sitting atop the boom while sailing downwind. People do that? Yeah, that’s something a rigger would do. Funny.

Totem is somewhere in the Atlantic, hopefully between Ascension and Barbados, if things haven’t gone horribly wrong. Find our current position and speed here! We will get comments at sea, so add a little interest to our day out in the big blue. We’ll be able to respond after we reach the Caribbean in late April.

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15 Responses to Mainsail Features: loosefoot versus attached foot

  1. sam April 15, 2016 at 1:29 pm #

    Love the tone of the article! 😀 Way to go sailmaker!

  2. Jonathan April 15, 2016 at 4:06 pm #

    Excellent, thanks. If I may ask…perhaps for a future post from the sailmaker. Need a new mizzen for Calypso, Gulfstar 50. Debating the pros and cons of partial v. full battens. (Mizzen has running backstays.) One sailmaker is proposing two full on the top two, two partial on the bottom two. Ending the battens in cars is optional. I’m assuming any full batten should be firmly attached to a car on the track, yes? Opinion on full v. partial? Thanks!

  3. Frank April 15, 2016 at 4:44 pm #

    So, would it be ok to disconnect the mains foot from the boom to get better performance?

    • Jamie Gifford April 23, 2016 at 12:54 pm #

      Yes. I recommend you try using the sail with foot hardware unattached before actually removing the hardware from the sail. If you like, then remove the hardware.

      The loosefoot allows to sail to maintain a better shape lower in the sail. There may be a miniscule performance gain, but any change will be very subtle. The benefit is in the sail shape setting up better and cloth along the foot not getting distorted by bias loading from the foot slides.

  4. Keith & Nicki - s/v Sionna April 15, 2016 at 9:15 pm #

    Hey Jamie – you’re good! And a fun read, too!

  5. Nat wilson April 16, 2016 at 1:42 am #

    I have been making sails for over 45 years for every kind of vessel large and small. Your general advise lacks considerations and knowledge of cloth , types of sail cuts best suited for loose footed sails to be slamming sound practice over time. Skill is king along with practice and proper finish. The English lost the Americas Cup with their loose footed sails. Egyptian cotton sailcloth and sailmakers in the great age of yachting made the best sails ever seen on this earth. They held speed records only now broken be GPS, carbon, computer cutting and satellite weather. In the case of J Boats in those days a good cotton sail went on the next boat. Now they go over the side.

    NSW

    • Jamie Gifford April 23, 2016 at 12:59 pm #

      Nat, 45 years a sailmaker suggests that you’d have more to offer than inane garbage you wrote here and on our Facebook page. So you take issue with my position on mainsail foot attachment, but please say something of substance. You did state wrongly that loosefoot requires special hardware and wrongly (and unsupported) that loosefoot has less performance. So please, tell me that you have something real to support this “sound practice” of attached main foot.

      I’ve never been good at self promotion (maybe you give lessons?), and perhaps that’s why you so quickly discard my experience. But what do you know of it? I can’t claim to have done sails for EVERY kind of vessel large and small, because it’s a stupid claim (nobody has). I have designed and built sails for Americas Cup (winner), Whitbread, BOC (winner), Vendee globe challenge (winner), maxi world champion (winners), mega yachts, classic yachts, dinghies, and many many types of cruising and racing boats of various sizes.

      As to cloth, I have experience, but clearly different than yours. See, it’s my belief that Egyptian cotton is best kept to long underwear. I can talk about involvement in Cuban Fiber development for ’92 Americas Cup or many custom cloth development programs or managing the best sailcloth testing facility in the world, but it’s all blather that nobody cares about. I do get your fondness for traditional sails/sailmaking/etc – I’m from Mystic, Connecticut and used to work at the Seaport, but to write-off all contemporary sailmaking except your own as inferior is juvenile and ignorant.

      Cotton sails, that is funny…

    • Keith & Nicki April 24, 2016 at 3:45 am #

      Nat, please. You clearly speak from ignorance and arrogance, not experience. What were you doing for those 45 years? Making cushions? Cotton has no other purpose on a sailing vessel.
      Oh, and a quick history lesson: The English lost the Americas Cup due to outdated hull design and poor tactics. Perhaps the loose-footed main made their defeat slightly less embarrassing, but the performance gained was not significant enough to save them.
      Cotton. Laughable!

  6. Jonathan April 16, 2016 at 2:35 pm #

    Cool, crossing the Amazon as we speak. Surely that is a landmark in a world cruise. Is the water color different that far out?

    • Behan April 24, 2016 at 7:18 am #

      Interestingly- we did encounter a color change, which wasn’t entirely expected. It was 250nm off the mouth of the Amazon and came with a current shift as well.

  7. Jeff Bander April 17, 2016 at 7:55 pm #

    Thanks for writing this up. It always seemed to me that a loose footed sail would provide a more wing-like shape. Yet, I’ve sailed aboard roughly 40 boats and can’t recall seeing a single loose footed mainsail. Puzzling? Like somehow a very sensible idea has simply fallen out of fashion.

  8. Michael May 7, 2016 at 10:18 pm #

    Thanks for this information. I’d not yet even considered loose footed main for my boat.

    This may be a dumb question, but do you reef a loose footed main the same way you do an attached one?

    Thanks,

    Mike
    http://www.FillingTheSails.com

    • Behan May 10, 2016 at 4:19 pm #

      the short answer is – yes!

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