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graystork2
07-15-2001, 11:02 AM
I'm building a 12' Skipjack by Stevenson. This is a first time family boat to be used only for daysailing on a small river. I don't like the aluminum pipe lateen rig reccommended because it detracts from the boat's traditional look. After looking at both the gaff and spritsail rigs, I've decided on the spritsail due to its simplicity. I would like to include a jib. However, the spritsail plans I have seen describe a rotating rig where the entire rig appears to rotate in the mast box/step. Is there any way to design this to take a jib? A swivel where the jibstay attaches to the top of the mast? Or just secure the mast and rely on the snotter to rotate around the mast when reaching or sailing free? Any thoughts regarding the benefits/problems with the spritsail rig also appreciated.

Thanks
Dave Thompson

Rob H
07-15-2001, 02:57 PM
I'll bet you'd be safe letting the mast remain fixed while the sail and snotter rotate around it.
Both of the sprit rigs I have used behaved that way,even though one of them was designed for the mast to rotate. The mast step had enough friction that it stayed put. No big deal.
One thing, though. You want to make sure that the sprit doesn't foul the jib when you tack. If it does, either shorten the sprit or move the attachment point of the snotter down the mast.

Mike Field
07-15-2001, 06:45 PM
What Rob says.

Fix the mast, if you want to. Otherwise treat it as though it were, and nothing much will move. (And if there's not enough space for a jib, consider a bowsprit.)

J. Dillon
07-15-2001, 10:01 PM
I've been sailing with a jib on my 18'sprit sail skiff for about a month. Occasionaly the sail does hang up if I try to hurry it across when tacking. Letting it come over on it's own solved that problem.

In persistent cases it did occur to me that a brail on the sail might also be a solution. That is when tacking, let the sheet go, brail up for a bit and when the sail and sheet come over on the new tack, let the brail go and sheet in.

JD

dadadata
07-22-2001, 09:39 AM
<<
However, the spritsail plans I have seen describe a rotating rig where the entire rig appears to rotate in the mast box/step. Is there any way to design this to take a jib?
A swivel where the jibstay attaches to the top of the mast? Or just secure the mast and rely on the snotter to rotate around the mast when reaching or sailing free? Any thoughts regarding the benefits/problems with the spritsail rig also appreciated.
>>

You have to realize that there were many approaches to the problem you describe in the Good Old Days and that surely some masts rotated and some did not.

The issue with the rotating mast seems to be mechanical. In the Good Old Etc, you held the snotter in place by causing it to jam on the mast and if necessary wetting it which caused the fiber rope to contract.

If friction is all that holds your sprit(s) up, you don't want the snotter rotating. You want the mast rotating.

With a more modern setup (fairleads, cleats, blocks, etc) the mast doesn't have to rotate.

Note that Thames Barges used enormous spritsails and there's not one word published about their masts rotating. Nuff said. it's only in the case of the el-cheapo and dead simple small boat sprits.

Todd Bradshaw
07-22-2001, 01:39 PM
As far as I know, the only real advantage to a rotating mast for a spritsail is that it helps keep snotter tension the same on both tacks and varying angles of attack. Seeing that the major advantage of a spritsail is it's simplicity, not high performance, it would sem that rotation should be encouraged when possible but really isn't all that big of a deal if it isn't possible.

The Springfield Fan Centerboard company lists a cast masthead cap with a swiveling fairlead atop it (designed, as I remember for a halyard on a lateen, etc.) but the same type of fitting could be used for hanging up a jib or jibstay on a rotating mast. Here again, it probably won't make an awful lot of difference in how the boat sails. Headstay or jib luff tension is going to be almost exclusively a direct result of the amount of mainsheet tension and the mast bend that it creates, forming a sort of self-tensioning jib luff and draft control - tight and forward while sailing to weather with a slacker luff and deeper draft off the wind.
Since the people sailing sprit rigs aren't generally out there trying to out-point or outrun a J-24, there is no reason that the rig can't work with or without a jib or a rotating mast.

Will
07-22-2001, 04:35 PM
My mast doesn't rotate that well, which doesn't seem to matter in light air . As the wind picks up I have a tack downhaul I set. With this set big forces are generated at the down haul as the boom is let out. I'll hear a certian noise ("kunk "),as the mast is finally forced to pivot .With no shrouds in the way we can let our boom out perpendicular to the mast when running .At this point we're showing sail more efficently than the Marconi rigged raceing dinks he ,he . A rotateing mast allows this with downhaul set . When landing down wind it's usually most convenient to simply toss the mainsheet forward and let the boom swing out over the bow , compleatly spilling its wind. This can come in handy out on the water too .You can spill the wind on any heading if things are getting out of hand , or you just need to stop and rest or bail .

So , I'm modifying my mast .I'm going to round the foot of the mast more and paint it with an epoxy graphite mix , putting the same stuff on the step and the partners .

Rob H
07-22-2001, 05:28 PM
Will, Does your sprit rig have a jib? Reason I ask is that my experience with such a rig was that the jib's luff tension pulling forward on the masthead acted to jam the mast at the step and partners so it didn't rotate, even though it was round its full length. The sail and snotter were both a lot freer to rotate than the mast itself. I guess that some high-tech gear and goo at the step and partners could change that balance, but that's not what sprit rigs are about, is it?
As far as I know, snotters have always used a little thumb cleat to keep them in place.

Rob H
07-22-2001, 05:39 PM
Ooh, clarification needed!
The snotter has a long eye-splice which is ring-hitched around the mast, with a thumbcleat keeping it from sliding down. That end does NOT rotate independent of the mast. But the SPRIT and its end of the snotter swing around with the sail.
There is enough free length in the snotter that the set of the sail remains about the same, even when the sail and sprit swing in tacking.

Will
07-22-2001, 07:15 PM
Rob, if you've got the thumb cleat you no longer need the ring hitch , you can use any fixed loop and it will rotate freely around the mast . I thought that was Dadas point . I don't have a jib and think it's not worthwile in such a small boat ,but to each his own .

Rob H
07-22-2001, 08:25 PM
Right you are, Will. I just re-read Datadata's reply.
But I would hate to see something as simple as a sprit rig get all tech-ed up with modern hardware, all for the sake of some marginal, thoeretical advantage. It's just not necessary!

dadadata
07-22-2001, 08:37 PM
The "original" small-boat snotter was something like a figure 8 that did not always use any hardware. You put the sprit heel into this thing, and you jammed it up the mast.

When I said "more modern" all I meant was a snotter with a purchase, a couple blocks perhaps, and a cleat or two for tying the snotter line off. In these cases the sprit has a slot, or a block attached to it, or a hole (dumb sheave) or some other fastening of sprit to the snotter tackle.

Sorry for being unclear. As far as I know sprit *booms* (ie, sharpie sails) always used tackle of some sort even if only a rudimentary sort.

Lots of tackle on spritsail sprits goes way back in time among the Dutch and English to a certain extent but these would be found on larger vessels. You can simplify and emulate this sort of rigging on a non-rotating small boat mast.

graystork2
07-23-2001, 08:50 PM
Originally posted by dadadata:
<<
However, the spritsail plans I have seen describe a rotating rig where the entire rig appears to rotate in the mast box/step. Is there any way to design this to take a jib?
A swivel where the jibstay attaches to the top of the mast? Or just secure the mast and rely on the snotter to rotate around the mast when reaching or sailing free? Any thoughts regarding the benefits/problems with the spritsail rig also appreciated.
>>

You have to realize that there were many approaches to the problem you describe in the Good Old Days and that surely some masts rotated and some did not.

The issue with the rotating mast seems to be mechanical. In the Good Old Etc, you held the snotter in place by causing it to jam on the mast and if necessary wetting it which caused the fiber rope to contract.

If friction is all that holds your sprit(s) up, you don't want the snotter rotating. You want the mast rotating.

With a more modern setup (fairleads, cleats, blocks, etc) the mast doesn't have to rotate.

Note that Thames Barges used enormous spritsails and there's not one word published about their masts rotating. Nuff said. it's only in the case of the el-cheapo and dead simple small boat sprits.

Thanks Da. What I'm going with is a eyesplice over a thumb cleat on the mast with the bitter end being led around a notch in the lower end of the sprit to a cleat about 2-3 foot up the sprit. I think this should give me strength I need and still alow the snotter to rotate enough when running free.

graystork2
07-23-2001, 08:53 PM
Originally posted by Todd Bradshaw:
As far as I know, the only real advantage to a rotating mast for a spritsail is that it helps keep snotter tension the same on both tacks and varying angles of attack. Seeing that the major advantage of a spritsail is it's simplicity, not high performance, it would sem that rotation should be encouraged when possible but really isn't all that big of a deal if it isn't possible.

The Springfield Fan Centerboard company lists a cast masthead cap with a swiveling fairlead atop it (designed, as I remember for a halyard on a lateen, etc.) but the same type of fitting could be used for hanging up a jib or jibstay on a rotating mast. Here again, it probably won't make an awful lot of difference in how the boat sails. Headstay or jib luff tension is going to be almost exclusively a direct result of the amount of mainsheet tension and the mast bend that it creates, forming a sort of self-tensioning jib luff and draft control - tight and forward while sailing to weather with a slacker luff and deeper draft off the wind.
Since the people sailing sprit rigs aren't generally out there trying to out-point or outrun a J-24, there is no reason that the rig can't work with or without a jib or a rotating mast.

Thanks Todd

Phil Young
07-23-2001, 09:55 PM
Plenty of small high performance catamarans have rotating masts and jibs. On a Hobie 16, which has this the forestay just attaches like normal to the front of the mast. The rotation doesn't seem to bother it.

Todd Bradshaw
07-23-2001, 10:55 PM
But - on a Hobie 16 the actual working forestay is the jib luff wire. The jib halyard is set up so that the regular forestay is slack while sailing. One of the big mistakes that new Hobie sailors often make is not putting enough tension on the jib halyard which causes terrible amounts of jib luff sag, even though the regular forestay may be pretty tight. Hobie masts also tend to bend from side to side much more than fore and aft because of their cross-section and the way the wires all lead to the front side of the mast to accomodate the rotation, so it might not be a good example to sight in relation to the sprit rig stuff.

Lazy Jack
07-27-2001, 08:59 AM
I've been having great success with my gunter rigged sailing dory this summer. Instead of a boom as in a normal leg-o-mutton, there is a horizontal sprit, chesepeake style notched at the end to catch the loop in the clew, and notched the same way at the oher to recieve the snotter. The only thing holding the sprit in place is the tention between the two. If the tension is set with the sprit along the center of the boat, as you wing it out on a run, the foot of the sail tightens as the tension of the snotter increases from being wrapped slightly around the mast and makes the sail self vanging eliminating the twist or tendancy to lift the clew as the sheeting loads switch from vertical, when sheeted in close, to horizontal when payed out. The foward end of the sprit projects about a foot in front of the mast but if I wait for the jib to tack before applying any tension on the jib sheet, it folds itself by the sprit with no trouble at all.

The snotter arrangement evolved to what I currently use which seems to work easily. I have two bronze eye straps placed vertically on the mast about eight inches above and below where the sprit crosses the mast. The snotter has a bronze round eye rigid quick snap spliced to one end. This end is snapped to the lower eyestrap the other goes through the notch on the sprit through a small microblock quicksnapped onto the upper eyestrap and straight down to a clam cleat mounted below the lower eyestrap. The block is actually left on the snotter when disassembled, so setting up simply means, setting the clew end of the sprit into the clew loop, running the end out while I stay at the mast, clipping the first snap hook to the lower eyestrap, clipping the block to the upper one, placing the line running between the two into the notch on the foward end of the sprit, letting go of the sprit and pulling downward on the bitter end of the snotter until acheiving the desired tension. Then I secure the bitter end of the snotter into the clam cleat. (The clam cleat being a plastic V groove channel with ribs that grab the line and pull it deeper into the groove as tension is applied.) Takes about ten minutes to write the description and about ten seconds to actually do. This arrangement allows you easily to adjust the draft of the sail for various wind conditions.