Mast hoops... Too big?

[Art Read]

My old skipper's daughter gave me six neat, old mast hoops from a turn of the century, gaff knockabout that has sadly been allowed to go to pieces. (She saved the hoops, at least, before the boat was allowed to leave her family, clever girl...)

Looking in Mr. Leather's "Gaff Rig Handbook", the only comment he has about hoop size is that they should "generally be about 1 1/4 times the diameter of the mast at the boom..." My recollection, and as best I can make out in my old pictures, is that the hoops on our old daysailer were maybe twice the mast diameter? In larger vessels the hoops usually seem to be proportionatly smaller, but I wonder if, on smaller craft, whether or not more "generous" hoops are common? Here's a shot of one of the hoops resting at about the position of the topmost hoop if under sail...

http://www.imagestation.com/picture/sraid48/pf9e0ec5d81abaa6845668e4a37ab276b/fcbb5780.jpg

They're really pretty interesting hoops. Never seen any like 'em before. They appear to have been made by steam bending round oak(?) stock to form 2/3 of the diameter and inserting a cast iron(?) rod fitted with eight parrels and two bronze ferruls each to finish the circle. I'd really love to use 'em if the conventional wisdom here doesn't think they're just way too big. (Inside diameter of the hoops is about 6 1/2" - Maximum diameter of the mast is 3 3/4" at the gaff jaws) Thoughts?

[ 01-25-2003, 01:19 PM: Message edited by: Art Read ]

[Ian G Wright]

Pretty,,,,,,,
The hoops are too big for *that* mast but would fit another, so you need another boat. QED.
But,,,,,,,,for a mast of the correct size for the hoops I'd guess you might need eight.
So, to sum up, you need to build a boat of about 25-30 ft and two hoops.
Good news eh?

IanW smile.gif

[ 01-25-2003, 01:41 PM: Message edited by: Ian G Wright ]

[Art Read]

"Good news eh?"

Well... Not exactly! ;)

I'm REALLY trying to talk myself into this... Just been looking at all my old pictures of "DUCHESS" in fact, trying to convince myself that her hoops weren't THAT much smaller, proportionaly, than these. You can "almost" make them out here...

http://www.imagestation.com/picture/sraid46/pb3a46eaca00c889a975bb9ab03315c1c/fcca474c.jpg

It appears in this picture that the tack and throat are holding the luff closer to the mast than the hoop diameter would otherwise allow. (Hense the angle of the hoops?)

I suppose my next question is whether or not if I do "try" these, and am dissapointed, what implications does that have for the sailmaker. I assume they will cut my main with the hoop size in mind. If I replace the big hoops with some smaller ones from Pert Lowell or somewhere similar, what will that do to the sail's fit? I assume, (again) that it would just mean the sail will lie closer to the mast at the luff and I'll have a little "extra" space at my boom and gaff toppings? Hmmmm...

[Ian G Wright]

Hmmmm,,,,,,,
The luff must be straight, so the fastening at the gooseneck, whatever it is, the fastenings/lashings to the hoops, and the point of attatchment to the gaff must all be in line with the halyard,and should not change when the gaff angle changes. Not easy even when the hoops are the right size.
Best have a word with your sailmaker I think.

IanW

[Todd Bradshaw]

The sailmaker would need to change the "tack set-back" (distance between the forward edge of the luff and the tack ring) and probably do the same thing at the throat. This gets involved with the shape of those corners and would not be easy to correct later if you decided to replace the hoops with more normal-sized ones. There is also a question raised about efficiency, though it's exact effects would be hard to predict accurately. The extra space between the mast and the luff will tend to "leak" more pressure from one side of the sail to the other, which is generally to be avoided as much as possible.

You could use them, but they probably wouldn't be the best choice.

[ 01-25-2003, 06:04 PM: Message edited by: Todd Bradshaw ]

[capt jake]

Art, maybe talking to Mike Field would help you out? I know he makes hoops and such. Wooden Boat fittings (http://www.woodenboatfittings.com.au/)

Good luck! smile.gif

[Mr.O]

Art: If you have old Wooden Boat magazines; look up #65 page 40 + ..Article on Pert Lowell and the Art of the Mast Hoop. Lists appropriate sizes, how to make hoops etc. Worth the look up. If you don't have a copy let me know I'll make you one and send it.. Jack

[Art Read]

Sigh... Wishfull thinking is dimming... I gotta admit, those hoops DO look awfully "generous" on my poor, wee, little mastie. Still, to my eye, the ones on "DUCHESS" don't look THAT much bigger do they? Maybe they were always oversized too, but we sailed her thirty-odd years like that without ever noticing. Or am I just seeing what I want to see? Ah, well... Any good ideas about how to make those antique hoops a size smaller? ;)

Jack... I'd really appreciate a peek at that article. I just looked through the four feet of bookshelf I have dedicated to WB and found #65 is one of the dozen or so back issues I lack. #64, #66, no problem... Double Sigh.

Todd... Not sure I really understand the "tack setback" as you describe it. As I envision things, the tack and throat cringles will be sewn in right at the appropriate corners of the sail's luff and the "positioning" of their attachment points will depend on this silly sparmaker, no? (But thanks for pointing out that detail, btw! Reason enough not to fool around with switching hoop sizes I guess...) What I have in mind at the moment is a simple "eye" at the boom just aft of the gooseneck and a swiveling, bronze "toggle" with two holes top and bottom set between the gaff jaws just aft of a wooden "tumbler" to ride against the mast. Tack and throat to be lashed or shackled to each with the standing end of the throat halyard shackled to the opposite end of the gaff "toggle". Sound reasonable?

While I'm worrying over this stuff... Does ANYBODY know of source for bronze eyebolts, lag type or regular, preferably shouldered? :confused:

[ 01-26-2003, 04:02 AM: Message edited by: Art Read ]

[Wooden Boat Fittings]

Art, as has been more-or-less said, the hoop needs to be about 25% larger than the largest mast cross-section.

This is the size we make ours, and from memory Pert Lowell uses the same figure.

Lowell's manufacturing method is to steam a long narrow lath and bend it about three times round itself on a former, rivetting the laminations to hold the whole lot together. Very traditional, and they look like this --

.
http://www.woodenboatfittings.com.au./public/masthoop.jpg
.

On the other hand, I have seen perfectly good (and very light) hoops made from plaited willow-wand with a sewn rawhide covering. And our hinged ones are perforce cut from marine ply.

The hoops you have, to be made the right size, would need about 8½" of material to be removed from them. From your photograph, that looks to be about half the length of the timber part. The obvious way to reduce the size of a hoop would be to remove that much of the wood (probably from one end, where the iron joins on, rather than from the middle,) bend the iron (which I would expect to be wrought rather than cast,) steam the hoop until you could bend it to the required radius, and then refasten the iron to the wood.

But I think you'd find that it would be simply impossible to bend the wood to such a tight radius, whatever sort of wood it is, and however much you were to steam it first.

The only other method that suggests itself, once you've removed the 8½" of wood, is to make a regular series of sawcuts for the full length of the remainder of the wooden part at, say, ¼" intervals, about seven-eighths of the way through the hoop from the inside. The removal of that much kerf material might then allow you to achieve the right radius after steaming. Once the wood were dry you could then refasten the iron and glue each of the now-closed-up sawcuts with (thickened) epoxy.

If you're prepared to sacrifice one of the hoops if necessary, this is the method I'd suggest you try.

My own view is that you'd probably be better off making new ones, and mounting the old ones on the wall of your study. smile.gif

Check your email for eye-bolts.

Mike

[J. Dillon]

Not trying to cut into wooden mast hoops, but what objection is there to all rope ( nylon or dacron) hoops with a toggle and eye for attachment to the mast ? :confused:

A rope hoop or grommet would be easier on the mast varnish, more readily removed, lighter, probably stronger and easily replaced at sea. smile.gif

Or are wooden mast hoops all tradition and esthetics ? :confused:

I use them all the time on "Carrianne", but she is only 18' long. ;)

JD

[Hwyl]

I'm not sure about the "tack set back" notes. My own feeling is; that the hoops only keep the sail close to the mast, in raising and lowering. If you are depending on the hoops to keep the sail close to the mast, then your luff is too slack. Yes, I'm a dyed in the wool racer, but I've seen lots of sail breakdowns because the sail is not attached properly and there is too much strain on slides, rope edgings, hoops, reef points (especially)and whatever.
Having said that, your hoops do appear to be a little unwieldly. I should imagine that there is a chance that the angle on the mast could become too great, causing the sail to bind up (on take down and hoisting).
I've never seen hoops like yours before. They have built in parrell balls. If you are determined to use these hoops, you could increase the diameter of some of the parrells (I guess they'd become parrell discs then. Personally. I'd save them to use or donate to another project.

[John Gearing]

Art,
Try Bristol Bronze for your bronze eyebolt.

[Jon Agne]

Hello Art,

For the eyebolt, why not used galvanized? I've tried to get decent bronze eyebolts and have never found anything worth the small fortune they want for the junk. Any good ship's chandlery will have excellent galvanized eyebolts (Crosby & Chicago, genuine forged in the US). They are practically twice as strong, and for the price, you can afford to change them out every 10 years or so!

As far as mast hoops go, stick with the 25% larger rule. You might get away with 30% depending on your sail. I have found that the best set of a gaff sail is when you get the luff adjusted properly so that the mast acts as the leading edge of the sail and the disturbance of airflow from the mast to the sail is minimized. When I have had my sail lashed to tightly or loosely to the hoops, I have had problems getting the first 2 or 3 feet of the sail to set correctly. I know it doesn't seem like much, but remember, the most power out of your sail comes from the forward quarter. Why do you think airplanes have de-ice protection for the leading of their wings?

As for the hoops, 125% seems to work fine. For instance, my mast is just shy of 9.5" in diameter and I use 11.5" hoops. They work great, but I think 12" would be just as good, but I don't want to re-learn the best way to lash the sail....once a year is enough!

Best,

Jon

[Todd Bradshaw]

Sorry Hwyl, but except for a few sails, like standing lugs, just cranking a halyard very tight is often not the thing to do for performance whether you're racing or cruising. It essentially "defeats" the luff curve that the sailmaker has built into the sail, changing the line of luff tension from the edge of the sail, aft a bit to a straight line between the tack ring and the throat (or tack ring and headboard on a Marconi). This moves the draft forward and flattens the sail, which is great on some points of sail and lousy on others.

Watch the area around the luff on an America's Cup boat some time as they go around the course. At times, there are a lot of wrinkles in the cloth just behind the mast. Those guys certainly have enough halyard-winch-power to pull them out, but when they want more draft for more sail-generated power (when punching through waves, etc.) they ease the halyard to get a slightly fuller sail.

On most gaff cruisers, like Art's D.H. it's rare for people to mess much with halyards on different points of sail, but I wouldn't intentionally start by cranking the throat halyard as tight as I could possibly get it. Once the wrinkles are gone, that's usually enough and hoops, slugs, slides etc. are an integral part of the luff system. They should be sharing some of the load in use and are a critical part of shaping the luff. In addition, the cross-cut panels of cloth will be striking the luff on a bias. Excessive, continual throat halyard tension is just going to stretch-out the luff.

Art, here is a drawing of a tack corner with a typical tack set-back. It's that little notch cut out of the corner that brings the sail's tack ring back so that it lines up properly with the tack fitting on the jaws or gooseneck. It's one of those little details that should be carefully measured on the boat before the sail is designed and cut. As simple as it it, if you screw it up and the fitting and tack ring don't line up properly, it can ruin the shape of the whole bottom half of the sail.

http://www.imagestation.com/picture/sraid48/p1a52d5510f3a1750c9b0131ce59d442d/fcb9d7e5.jpg

If bigger hoops are used, the resulting larger space between the mast and the sail's luff reduces the amount of set-back needed until at some point, no set-back is needed at all, as shown here - same mast, gooseneck and boom, the only difference is that the sail is farther back because of the bigger hoops and the set-back has been reduced to make up for it.

http://www.imagestation.com/picture/sraid48/pb1b5c1119de599b37626142ff8d06f88/fcb9d7d7.jpg

Aside from increasing wind pressure leakage and the possibility of whatever change this system might make in mast-induced turbulence (which is hard to guestimate, but probably not much) the second system would work fine if the set-back was adjusted as needed during the sail-design stage for bigger hoops. If, however, you later decide to replace the big hoops with "normal" ones, the sail will move closer to the mast and you will either need to move the boom's tack fitting to match, or have the sail's corner taken apart and a set-back added so that it ends up looking like the first drawing. That's not a cheap operation.

Note that I said the hoops, slides, etc. need to be an integral, load-bearing part of the system. They do - but even so, they bear much lighter loads than the tack ring and throat ring or headboard. It's often possible to take the sail from the second drawing (no set-back) and attach it with smaller hoops, closer to the mast like in the first drawing, but without re-cutting the corner and adding a set-back. The now excess fabric there allows it to reach the boom fitting without a problem. It's actually kind of slack. Unfortunately, this moves most of the load that the tack fitting is supposed to carry to the bottom mast hoop (or slug, slide etc. on different rigs) and to the first slide, roband or whatever happens to be in use to attach the sail to the boom.

That's what breaks things - re-assigning high amounts of stress to fittings that were never supposed to have it in the first place. Sometimes it's a matter of the sailmaker failing to design and build-in the right amount of setback. Other times it can be caused by sailors switching or changing fittings. I've had sails come in for repair where the owner had used whatever he could find and installed three or four different types or sizes of slugs on the same mainsail luff or where they innocently changed to a different sized tack shackle which completely throws-off the setback amount. Then they can't figure out why the shape is so bad or why some of the slugs tore out.

[ 01-26-2003, 05:04 PM: Message edited by: Todd Bradshaw ]

[Hwyl]

I think we're in agreement Todd, perhaps I should have said "light load". I do know all about the roach in the luff and have sailed with (a comparatively) slack luff. I think that you would agree however, that in general one sees cruising boats and especially Gaff boats with the luff too slack and the foot too tight.
Thanks for taking the time to post the drawings.

[Todd Bradshaw]

Yep. It's also worth noting that a gaff main that really sets nicely is a work of art that's not easy to achieve. With fabric that stretches a lot more in some directions than others, bordered on three sides with spars that may or may not flex, attached to each other with movable, non-rigid joints and fasteners and held aloft by rope, a little bit of over-or-under-tensioning can make a big difference.

[Wooden Boat Fittings]

Originally posted by Jon Agne:
,,, I don't want to re-learn the best way to lash the sail....once a year is enough! Ah. That's the rationale for our hinged masthoops, Jon -- on and off in a (comparative smile.gif ) flash, and without undressing the mast.
.

[John B]

I laminated mine around a pipe + packers. I was told that you need to get a knuckle between the mast and the hoop to avoid chattering and hanging up on the hoist and douse. In my case this means a less than 25% clearance but I have no problems with this. I also made my saddle and mainsail tack match the hoops to take the nock/setback element out of the equation for the sailmaker.

Those hoops Art. Neat, very neat. too big unfortunately.

[ 01-27-2003, 03:30 PM: Message edited by: John B ]

[Mike Field]

Not sure what you mean by that knuckle JohnB, but another way of solving the problem is to run a light line down the outside of the hoops (or even inside them,) and attach each hoop to the line. This keeps them all nicely separated by the right amount and helps prevent jamming. (It can make a useful downhaul too, if you don't use the fall of the halyard for that.)
.

[John B]

To find the knuckle, Mike,place your finger on the letter "p" on your keyboard and look approximately 50mm below and slightly to the right. there's one there, plus some others depending on your past jobs.

If you can shove a finger between the hoop and the mast , you won't get the chatter.

I tried the messenger line Mike. tied between the hoops. I found it unecessary( because the hoops don't hang up) and in fact, it became a problem because when the sail is down, all the spare line (loops of it)had a habit of hooking up on just about anything... a cleat, winch ,whatever...
On a hoist one day I removed it assertively and colourfully with a knife.

[Andrew Craig-Bennett]

I use a lacing....

Partly because that's what the boat came with, partly because we have roller reefing and partly because I cannot decide what size of hoop I would need. Mast diameter is 7", but the worm gear roller reefing sets the luff further back from the mast than might be the case with points reefing. The luff is about 5" from the mast.

[Mike Field]

Aahhh. I see. I thought you were talking about some sort of fancy design feature on the hoop,,,,

I think the thing about the 25% percentage over-size is that that gets the hoop setting at an angle to the mast that has been shown not to jam. But there's no magic to the number 25, and if some other size works on a particular rig then it works on that rig.

Just don't have that knuckle there while the 1st Mate tallies on the halyard, that's all,,,,
.

[Mike Field]

Oh yes, and I've also found that putting a large radius on the inside corners of the hoops works well too.
.

[Art Read]

These look more "reasonable"?

http://www.imagestation.com/picture/sraid52/p384119ede56ecec2054266aac0124658/fc9ca551.jpg

(And thanks for all the input folks...)

[ 02-20-2003, 02:45 AM: Message edited by: Art Read ]