Reefpoints in an old Sabot sail

[Thorne]

I use an old Sabot sail on my dory skiff, with the tube just folded over and grommeted for robands. Very funky but, hey, it works!

Since I picked up a smaller jib on eBay, I want to put in a set of reefpoints so I can change out my large jib (nearly the size of the main) for the smaller one and keep sailing in higher winds.

I'm building a gaff-jawed boom so the nettles can be tied to it, as opposed to the current sprit-boom that angles down to the clew. But otherwise I intend to leave the sail loose-footed, and would do so even if (I won't, but if) the foot roach was removed.

The Sabot sail has a roach (and batten pockets) on both the leech and the foot, but I rarely put the battens in place. Yes, this results in some unsightly flogging of the leech, but the foot seems to handle it better.

http://www.luckhardt.com/sbs/sbs-Images/8.jpg

First question: how important is it to have the nettles tied to a boom on a dinghy sail, as opposed to being tied around a bundle of sail that hangs free in the same curve as the roach? It seems to me that in high winds the reef would be better behaved tied to the boom, but I've never had a loose-footed mainsail before.

Second question: Assuming that I go with the gaff-jaw boom, should I lay the reef points out in the same curve as the roach on the bottom, or should the reefpoints be in a relatively straight line from reef tack to reef clue? In other words, should I build the reef with just enough curve to match the camber of the sail, not the roach?

The reason I'm asking is that Marino says about reef layout in several places in his book , "The curve on a boomless or loose-foot sail will be the same as the foot curve". Can I assume he's not talking about sails with a roach in the foot?

Third question: Should I set the reef to take up about the same percentage of the main as I lose with the smaller jib? I'm assuming that I should strive for the same rough sail size balance, but am not sure.

Thanks!

[Todd Bradshaw]

The first thing I would do is put the leech battens back in and leave them in. What is happening on the leech is nearly always far more important than what is happening along the foot. It will also extend the life of your sail and get rid of some of those wrinkles along the leech before they turn into breaks in the cloth from flapping.

Foot round is generally not a good idea on a sprit-boom sail as it tends to be very hard to support. The tension will be focused in a straight line between the clew and tack corners and anything falling outside of that line (like foot round) generally does little other than flap. It's often possible to reduce the snotter tension enough to get the round to fill, but not without also inducing an awful lot of draft. Conditions where you would want to crank the snotter tighter and flatten the sail (high winds, very light winds or when beating to windward) tend to pull the tack-to-clew line tight, like a crease, and leave the round flapping uselessly in the wind. Hacking off a good bit of the foot round might not be a bad idea if you intend to continue using a sprit-boom. In any case, adjusting the snotter to make that abnormally round foot fill, at the expense of the shape of the rest of the sail, is likely a mistake. More snotter tension might also help cure that reverse mast bend you're showing, which is also causing most of that bloop in the main along the aft side of the mast.

Even for a loose-footed sail with a conventional boom, that's an unusually large amount of foot round. There is no specific rule of thumb for round on loose feet. It's usually left up to the builder's eye to make a pleasing curve. Cutting the foot straight with no round is possible, but usually looks very chopped-off and kind of ugly. On a sail that size, something in the 2"-3" range with maximum round about 45% of the foot's length aft of the tack would be typical. If you do ever decide to take the plunge and re-cut the foot, you can generally bend a batten between the tack, the new max depth point and the clew, draw a smooth curved line along the batten and cut it. Keep the aft end of the curve fairly flat as a dramatic curve along the aft portion of a loose foot tends to flap.

We generally want a reefed sail to be somewhat flatter than it is at full height. I'll normally use a slightly shallower curve for the reef points than the curve of the foot. A second reef may be shallower still. This takes some draft out of the bottom third of the reefed sail, though the difference between adjusting the curves and simply following the foot shape isn't huge, since the vast majority of the tension and shape is coming from the tack and clew corners. In any case, since the foot of that sail has an excessive amount of round, I would not echo that drastic curve with the reef grommets.

Since the corners are doing the real work, there often really isn't much of anything to be gained by tying the reef lines of a loose-footed sail around the boom. Some folks even think it increases the chances of breaking the boom. However, it may be worth trying. High winds and the increased sheet tensions that go with them will tend to bend the boom. Where and how much will depend on the boom's construction and how the mainsheet attaches. If you maintain a loose foot and tie the reefs just to the bundled sail, then bend the boom, the tack and clew corners attached to the ends of the boom will move slightly closer together (a bent boom is shorter from tack to clew than a non-bent boom). This will actually increase draft slightly along the bottom third or so of the sail. On the other hand, if your sail is attached along the boom (laced, slugs, slides, robands, boltrope or even reef ties surrounding the boom) and you bend the boom with mainsheet tension the boom gets shorter, but in the middle, it takes the sail with it - eating up some of the effect of the foot curve and lower sail draft. The lower part of the sail gets slightly flatter and is depowered. Depending on the conditions and the characteristics of that sailplan on that hull, you may just want to reduce sail area or you may want to both reduce area and flatten the main as much as possible - and if so, you may get a flatter sail by reefing with the reefs tied around the boom. Experiment and see what works best. In any case, the first goal would be to worry a lot more about the upper two thirds of the sail. You've got about 25% of your mainsail working in the photo and the rest (including nearly the entire luff - the part that is most valuable) is just along for the ride. If the jib suddenly fell off, the boat would probably stall out so fast it would pitch-pole. :)

If you have a current configuration that seems to balance well, it might be worth drawing it out to see just where the CE is (both fore-and-aft and height above the waterline). Then you can do the same for various reefed configurations (reefed main with small jib, reefed main with big jib, un-reefed main with small jib, etc.) to see how they compare. It's probably a better bet than just guessing on reef size, though most typical small boat reefs will take out something in the range of 15%-18% of sail area.

[Thorne]

Thanks, Todd.

I know that the current sail and spar configuration leaves a LOT to be desired. I'm using a sail designed for a flexi mast on a stiff mast, and on a boat much heavier and larger than designed for, etc etc etc.

http://www.luckhardt.com/ls-sail1.jpg

The sail is usually trimmed a bit better than in the first photo (I'll blame it on the woife), but the crease along the spritboom does get worse when I crank the snotter tighter (as can be seen in the photo just above with a different much older cotton sail). That is just one reason why I'm building a boom to see if I can get a slightly better sail shape.

I was also inspired by your posts and artwork on how a gaff-jaw boom can be used as a good sail-shaping tool. I won't make you post that all again, but will try the sheeting setup as shown, including running the sheet forward and then down the mast to pull the jaws of the boom down when the sheet is tightened.

http://www.woodenboatvb.com/vbulletin/upload/showthread.php?t=54869&highlight=boom+sail+mainsheet
http://www.imagestation.com/picture/sraid112/pf8c80fa7208687c581036b93ab02c789/f9045858.jpg

[Thorne]

I'm wondering what dimensions I should make the boom, using clear VG DF? Sail is only 38 sq. ft., but if I'm going to lash the sail to the boom to keep it flat when reefed, it looks like I want a reasonably stiff / inflexible boom. It may also need to be stiffer than usual if I'm going to correct that forward bend in the mast by sheeting it down hard.

I've got an 8' 2x4, just not sure what to cut it down to. The old Sabot boom is about 1 1/8" thick x 2 1/4" wide x 7' 8" long -- it is painted but I think it is DF not spruce by what I can see of the grain and by weight.

Should I try 1.5" thick x 3" wide and see what happens? I can test it unfinished and then plane off any excess (other than where the oak jaws attach).

http://www.luckhardt.com/gaffjaws1.jpg

[Todd Bradshaw]

The 3" value might be a bit more than needed. I've always had pretty good luck with the small-boat spar formulas in Oughtred's book. For a round boom, he specifies a diameter of 1:56 for high-quality fir or spruce and maybe adding an additional 1/8" of diameter for lesser quality woods like pine. Tapering suggestions generate diameters of about 80%-85% of maximum forward and 70% of maximum diameter aft. For a round boom of that length from non-aircraft grade stock, it would end up about 1.75" maximum diameter. I suspect that's plenty for such a small sail and can't imagine the boom bending a whole hell of a lot while sailing, especially if you avoid attaching the sheet mid-boom where sheeting would tend to put a lot more boom-bending force on the package. Nice jaws, by the way!

[Thorne]

Thanks...we shall see if they can take the strain or crack.

I have Oughtred's book and will re-read that portion tonight.

Do you think that a round boom would be better with gaff jaws than a rectangular-section boom? I was planning on the latter to give additional stiffness...is a round boom more traditional?

[Todd Bradshaw]

I think you could go either round or rectangular and wind up looking traditional (or a combination of the two with corners at the jaws and then morphing into a round. A vertical oval is also really classy looking, though a bit more work). I don't know enough engineering to be able to say what the strength/flex difference would be between the various types, but in any case, I don't expect it will bend enough to cause much trouble with that sail size.

[Todd Bradshaw]

You may also want to bore a pair of holes, or maybe a couple pairs (notches really - they look kind of like limber holes) on the inside edges of the jaws before mounting them. They come in very handy for hanging blocks, attaching the sail's tack ring or a downhaul line. Blocks usually hang a bit aft of the mast as shown, downhauls and holes for tack lashing are usually up pretty close to the mast. They don't need to be very big. If you can thread a hunk of 1/4" line through them, that's usually plenty on a small boat.

http://webpages.charter.net/tbradshaw/JAWS%20copy.jpg

[Thorne]

Thanks, Todd, I'll give it a try. Will go for the vertical oval boom a la Oughtred and see how it looks, and will also try the notch as you recommend above.

I have a 4-eye mast band that I plan to put on the top of the mast, currently just pierced for a line with two blocks for the jib and main halyards. That should let me hang two more small blocks for a topping lift on one side and a flag halyard on the other.

Some line questions.

Mainsheet - Assuming I keep my rope traveller, should the main sheet end on the block/sliding ring at the rope traveller, the other end running forward along the boom to the block under the boom jaws, then down to the block on the forward thwart?

Nettles - Someone suggested using braided line rather than laid, and I'm assuming it should be a small diameter for a sail this size. I have some 6mm Hempex 3-strand (which looks a bit big), can get braided plain cotton no-core sashcord, or can order other line from R&W Rope. Even though the sail is FAR from traditional, I've been sticking with a "trad" theme for lines on the boat, using Hempex or even Manilia line where possible (and wise).

Topping lift - Ditto the Hempex 6mm. Was thinking that I might be able to use this also as a crude brailing line for bringing the aft end of the boom up against the mast -- after unhooking the parrel line from the gaff jaws, of course. The free end could be used to wrap the boom and sail roughly up against the mast, as I currently use the mainsheet to do with the spritboom.

[Todd Bradshaw]

Mainsheet - that's probably how I would do it - probably eye-splice the aft end of the sheet to the ring or block's becket and let it ride back and forth on the traveler. You could always start at the boom's tail end instead, and add another up-and-down for more purchase by going down to the traveler block and then back up to the boom and forward, but I don't think you will really need it (it also drastically lengthens the amount of line needed for the sheet and how much you have to trim at each tack or especially a broad-reach-to broad reach jibe). As long as you have some sort of mainsheet cleat, belaying post, snubbing winch etc. to give your hand some help in high winds, the simple, basic system seems to work fine up into the 75-90 square-foot sail range.

Nettles - I usually use 3/16" 3-strand and try to find something soft enough to hang naturally as it looks more orderly than stiffer stuff that tends to hold kinks. There is very little strain on nettles and most 1/8" line would work fine, but to my eye it looks a bit puny. The 6mm is certainly overkill on the topping lift and nettles from a strength perspective, but if you already have it and the scale looks reasonable I don't see any reason that you couldn't try it.

[Thorne]

I'll order more line from R&W, as Waste Marine didn't have anything traditional and neither did my local chandlery, Whale Point in Richmond. Got the metal grommets set in the sail today, so now I need to wait until I can set up the sail and boom to see just how long the nettles need to be.

Got the new boom built this weekend, gaff jaws glued on, and a 4-eye Davey mast band transferred from an old mast to my current one. I'll set up the topping lift on one side, flag halyard on the other. Now I can run flags up the mast and get 'em jammed in the mainsail halyard block!

;0 )


http://www.luckhardt.com/newestboom1.jpg

http://www.luckhardt.com/newestboom2.jpg

[Thorne]

I've got the grommets set and am waiting for my order of 1/8" natural hemp line for the nettles to come in from R&W.

I'll run the mainsheet as per your artwork.

The mainsail has a pennon/pendant/line running from the tack of the sail down to the base of the mast to hold it down. Do you think that I should run that line through a hole in the gaff jaws / boom and belay it as usual, or shorten the line and attach it to the top of the boom, using either a separate line from the boom or the mainsheet to pull the sail down?

[Todd Bradshaw]

I'd probably connect the tack grommet to the jaws. The best way may depend upon the setback distance between the aft side of the mast and the tack grommet. That's a pretty critical spacing to get right in order for that corner to set nicely. Sometimes you can tie a loop through those little "limber holes" on the jaws and catch the sail's grommet above the boom. The knot ends up below the jaws and the loose tail hangs below the knot and boom and can be cleated below as a downhaul.

Nothing is set in stone though. Don't hesitate to experiment and see what yields the smoothest sail shape in that area.

[BillyBudd]

Enjoyable to read Todd's and Thorne's comments. I'd like to join in to ask a few questions about the Sabot and its sail rigs. It seems that Sabot was born in 1939 in an article by MacGregor in the old Rudder magazine. That article has a drawing of MacG's thoughts about the pram and its rig -- he shows a sliding gunter (stowable spars) and (I'm not sure) a foot lashed to the boom -- but it could be loose footed too. There's one line of reefs. I'd also like to hear comments about home "designing" this little sail. Is it doable for the amateur? What to think about broadseams and roach/battens and that foot? (Will build 2 Sabots this spring.)

My question for Todd is: what's the best for the 8' pram? A loose or laced foot?

I'm going to guess that Thorne's used Sabot sail is from one of the west coast variations -- El Toro or what I think are called the Corsair types.

BTW, can forward to both of you, either of you, the 1939 drawing of the Sabot w/ sail. Let me know.

[Thorne]

Nope, out here we have both the Sabot and Sabotina, and the Mighty Bullship (aka El Toro). Only difference (that I'm aware of) between Sabot and Sabotina is the latter has a daggerboard, the former a leeboard.

http://www.boatdesigns.com/products.asp?dept=758

My sail was from an old gentleman who only rowed his Sabot and didn't need the sailing rig, so I got mast, boom, sail, and rudder. Ain't Craigslist wunnerful!

Why build Sabots? There should be plenty of older ones around, as the class has largely been replaced by the Bullships.

If you are going to build a one-design racing boat, I'd stick closely to the plans and specs, otherwise you get the worst of both worlds -- a racing boat that can't be officially raced. And there are lots of used Sabot sails around, or Sailrite.com will have the kits.

Here's our earlier discussion on Sabots -
http://www.woodenboatvb.com/vbulletin/upload/archive/index.php/t-67871.html


Best of luck!

[Todd Bradshaw]

I don't know what the class rules specify in terms of going laced-foot or loose-foot, but the sail could be cut either way. If you want to spend the time to tweak the outhaul as you change from upwind to downwind, you might see a slight difference in performance by having another adjustment available. On the other hand, if like most people, you set your outhaul on your loose-footed sail and leave it there all afternoon, don't expect to see any gains in your VMG.

There is a fairly important difference though in how the two sails would be cut at the bottom and they are not interchangable. In a very over-simplified nutshell for illustration purposes, the bottom fabric panel of a sail will generally have a straight side and a curved side. If we want to lace it to a boom, we use the straight side for the foot edge on the sail's bottom and sew the curved side to the next fabric panel above. The curve creates draft and shape, the straight brings it back in, forming a shelf-foot where it needs to be attached to the straight boom. For a loose-footed version, we would normally use the curved edge of the panel as the bottom and sew the straight edge to the panel above. In the process, we might further split the foot panel into sections with a couple of vertical seams to allow some broadseaming to give the sail's bottom a bit of a cupped shape. Either will work and they aren't quite that simple in real life, but the person who believes that their sail can be used either loose or laced on and works just as well either way is usually mistaken.

If you're building your own sails (whether laced foot or loose) it's probably well worth considering computer-cut kits with the shape already plotted in. Small, shapey sails are pretty tricky cuts because even four-ounce Dacron is proportionally pretty stiff (kind of like trying to build a 12' dory from 3/4" plywood). What you sew into it is the shape you will have and there is little ability to correct or modify it by pulling strings, the way you might on a bigger sail. Sailmaking itself is mostly just a lot of tedious grunt-work. It's the designing and shaping that's tricky. Unless you're used to eye-balling sail cuts it may be a better bet to let the machine figure out the shape so that you can concentrate on the craftsmanship without also having to worry about getting all that work done and having shape problems.

[BillyBudd]

Thanks to both. Building the Sabot here in New England is based on a) I need a reliably stable dink to get to and from our mooring, b) lots of the rowing only Sabots where we sail but none knocking about for sale, and c) would like to build one with the old sliding gunter rig and a leeboard. Todd, sounds like the computerized kit idea the best. Cheers.

[Thorne]

Well, I got my reefpoints and gaff jaw boom mostly done, and tried it all out on the boat in the backyard...er...boatshop.

I changed the blocks around on the boom after the boat pics, putting the larger wooden one near the jaws, and adding a small bronze block in the center of the boom.

http://www.luckhardt.com/gaffjawblock2.jpg

http://www.luckhardt.com/boomcenterblock.jpg

http://www.luckhardt.com/boomendblock.jpg

Here's the rig on the mast, pardon the mess and coiled line - I hadn't cut the reefing lines yet.

http://www.luckhardt.com/boomrigged1.jpg

And reefed
http://www.luckhardt.com/gaffjawboomreef1.jpg

[Thorne]

Unreefed on spritboom, sprit in the usual position on the mast.
http://www.luckhardt.com/spritboom-notreefed.jpg

Reefed with sprit in usual position -
http://www.luckhardt.com/spritboomeef1.jpg
http://www.luckhardt.com/spritboomreef1.jpg

And here it is sorta kinda reefed on my lowered spritboom - obviously need to work on the outhaul and reefing lines a bit...
http://www.luckhardt.com/spritboomreef2.jpg

[Wild Wassa]

I don't think I'll ever understand this site.

That is a Sabot sail, one of the smallest sails known to man and almost the smallest sail on kid's training boats. Reef points in a Sabot sail, Thorne?

Are you taking the mickey out on we Sailors, Thorne. It is hard to not feel that you are for a sailor coming from the school of ... 'Big sails win big races'.

Warren.

[Thorne]

Moi, take a "mickey"?? Nevaire!

;0 )

Wot's this "race" thingie you speak of?

Seriously, the unfortunates that I hornswaggle in to crewing for me get very nervous when all that water comes pouring over the rail. I, of course, am calmness personified and never ever shout things like, "Bail, damn your eyes! We's all gonna die!"...

Considering that I occasionally (and foolishly) venture out on SF Bay and other windy places, I need all the help I can get. And with this same teensey sail up I've broken two masts, two bowsprits, and the bank account -- so reefpoints it is, mayties.

I have a significantly smaller jib that I plan to fly when the breezes pipe up, so the reefed sail is an attempt to balance the rig with that smaller jib up - otherwise it gets savage weather helm.

[Wild Wassa]

Thorne G'day Skipper. Well, William Fife, the Scottish designer said, "A boat should be fast and bonnie."

Your boat is beautiful so it only holds true Skipper, that she should also be fast and slippery.

Since you employ Fife's attitude of keeping the boat light, "I've broken two masts" and "two bowsprits," then one can only feel she is inherently in need of more race trim.

Fife designed his boats with inherant weaknesses. So light in their rigging and fittings, that if a boat broke, he would step-up to the next size or strength of what ever broke. Fife never shortened the sail area in an attempt to make a boat more sea-worthy Skipper.

When the designer Michael Storer, our own WBF Member 'boatmik' was asked, "What makes a boat seaworthy?" during the Furled Sails interview, recently. His reply was, "The main thing I would agrue is performance! If the boat will go in any direction in any reasonable conditions in an efficient and effective way, that is your marjin of safety. The boat will take care of you if the boat is properly designed. If the centre board is big enough. If the sails work properly, to depower if gusts hit If the boat stays on its line when it heals and doesn't change its direction" ... "the boat will take care of you" ... see Skipper? "Big sails win big races" isn't about racing it is about improving the boat's performance to make her more seaworthy and handle the conditions.

Thorne, I think that I would rather balance the boat properly, and stay with her designer's sails or improve the quality of the sails, than carry a sail that isn't designed to do that. I once wrote, "reefing is for rookies," and I still mean it.

... because if you are out in 30-50 and have to reef, ... it is too late anyway, you should have anticipated the change coming Skipper.

When my Skipper wants to reef the main, I give him heaps and tell him that I drive the sails, just don't round us up Skipper, I'll exhaust the sails and do the depowering, just don't lose it.

I'm not one for changing the sea-worthyness of a boat to cater for the crew. With all respects to your crew. Tell your crew to step up! If that piddly little sail fails you an depowers too quickly after a gust, it will spit your crew out the back door ... it will be the wrong rail in the water.

Warren.

[Shalfleet]

I understand why people want to reef, especially in keel boats, but very few Thistle sailors bother. When it gets really windy, we drop the traveler, yank on the vang, pull the cunningham and outhaul, and hike like crazy to keep the boat in balance. If we still can't keep the boat flat we ease the mainsheet and jib and flog the sails (effective but expensive). When sailing upwind, we often pinch, letting the jib luff a bit to spill wind and depower. Uffa Fox wrote about the benefits of sailing flat by easing the main and most racing sailors take this route today. I'm just not sure how to do this stuff with a traditional rig when most of these controls and even hiking straps don't exist....
Dale

[Wild Wassa]

"What is this race thing that you speak of ..." -Thorne.

" ... we often pinch, letting the jib luff a bit to spill wind and depower." -Shallfleet.

Racing sailors sail differently to cruising sailors. I watch us and other race sailors when we go on a recreational cruise, we cant. Nothing changes except the calling of tactics ... they are halved for some.

Racing is all about gaining height and keeping the sail's efficiency at the maximum % and milking the wind/sail combinations for every last drop of power. That is what keeps us safe. Letting the wind dictate our level of boat skill, over being skillfull ... never ever happens.

On each beat/work, if we can gain even 2 boat widths over others to windward, no matter what the conditions, we curse ourselves when we fail to take it or just don't get it right.

Scalloping or as you wrote Shallfleet? "we often pinch" (I'm guessing it is the same thing) then we're on the money when we can ... but, off ... on ... off ... on.

Sailing to the maximum efficiency is the joy of doing it, so reefing is the absolutely last resort and done when we are losing ground to others because we are overpowered.

We do set up reefing lines when at sea or in long distance races as a matter of course ... but I'm pleased to say that not once this year did we put in a reef ... although we did drop the genoa before a race once and change to a jib and the sailors that reefed their mains were short sailed as always ... big sails win big races.

The guys who beat us in this year's Micro Tonner Championship, Grahme Wykes and Paul Patotowicz, his crew. They might have a reef in ... but look at the position of the boom and the traveller.


http://i225.photobucket.com/albums/dd301/WildWassa/PaulandJohn-1.jpg


Warren.

[Thorne]

The reefing system worked very well in strong winds at this weekend's Big Lagoon Messabout. Not too much of a reef as it turns out, and balanced well with the smaller jib with still a fair bit of weather helm.

http://www.luckhardt.com/bl_boats_beached.jpg
More photos to follow...