Code 0 Bowsprit Length

Jan 2, 2017
765
O'Day & Islander 322 & 37 Scottsdale, AZ & Owls Head, ME
I have a Selden bowsprit extended the max unsupported length of 35.5” to fly my asymmetrical spinnaker. I’d like to add a Code 0 but the Selden specs say I’d have to reduce the unsupported length to 17”. If I do that the furling line wouldn’t clear the pulpit. It seems this would be a common problem. How have others handled it?
The only solution I can see would be to reduce the foot and leech of the sail until the 35.5” sprit could handle it. Any thoughts? Thanks.
 
Last edited:
Jan 2, 2017
765
O'Day & Islander 322 & 37 Scottsdale, AZ & Owls Head, ME
Thanks Will (and Jackdaw) that’s pretty neat.
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
I would think that when close reaching the forces on the tack might be more sideways than vertical. While the bobstay helps with the vertical force it won’t help the unsupported length sideways. Having said that, it does seem to be somewhat an accepted solution so maybe I’m overthinking it.
 

weinie

.
Sep 6, 2010
1,297
Jeanneau 349 port washington, ny
The luff tensions on a zero needs to be much greater than on an asym. Sometimes going 2:1 purchase on the halyard is necessary to keep the luff from sagging.
 
Jan 2, 2017
765
O'Day & Islander 322 & 37 Scottsdale, AZ & Owls Head, ME
I would think that when close reaching the forces on the tack might be more sideways than vertical. While the bobstay helps with the vertical force it won’t help the unsupported length sideways. Having said that, it does seem to be somewhat an accepted solution so maybe I’m overthinking it.
I have the same concern, Weinie. I’m leaning towards a scaled down 0. After all I’m not racing, just want a light wind closereach sail.
 
Oct 31, 2012
464
Hunter 2008 H25 Lake Wabamun
I would not want to exceed the specs from a production Sprit. As stated earlier, luff tension on the Code 0 is much greater than on a asym. I built my own bowsprit a few years ago to fly the Code 0. Last year I extended it from 24” to 36” to be able to fly both head sails like a cutter rig.
I tend to over build things so was not too concerned with the extension not being able to handle the load. So far it’s working just fine
 
Oct 19, 2017
7,733
O'Day 19 Littleton, NH
I would think that when close reaching the forces on the tack might be more sideways than vertical.
That is a legitimate concern that I hasn't considered. However, it would always be along the angle of the stay. As you put pressure on the cable, the cable flexes (deflects) over towards one side or another but force is still along the tension line of the cable. It's like putting your finger at the middle of your stay and pulling off to one side. The new angle of deflection is the new angle of force. Then do it again between your first, half way position, and the 1/4 position, a little more deflection and change to the force vectors. Do this until you have a continuous curve of the cable. Whatever angle that is at the articulating connection to the bowsprit, that is The angle of force.
If your stay is slack and the headsail is allowed to pull from the side, then you are right, the sideways angle needs to be braced against. But, keep the cable tight and the forces will be greater but in line with the stay.
- Will (Dragonfly)
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
Whatever angle that is at the articulating connection to the bowsprit, that is The angle of force.
But does the sprit bracket articulate? My impression was that the bracket would hold the pole straight forward, so the bobstay force vector is always straight down. Once the sprit starts to deflect then yes the force vector will be more toward center again, but by then isn’t the pole bent and kinked?
 
Oct 19, 2017
7,733
O'Day 19 Littleton, NH
But does the sprit bracket articulate?
I was referring to the forces imposed upon the spirit by the stay. Where I said cable, I should have said stay cable. Sorry for my lack of clarity. The bottom end of the luff cable or stay is usually connected by an articulating connector like a 'u' shaped screw shackle. Because it is free to move, then where ever the forces are directed, the stay cable points to. Since it is pulled tight, the vast majority of the force vectors are upwards.
- Will (Dragonfly)
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
I was referring to the forces imposed upon the spirit by the stay. Where I said cable, I should have said stay cable. Sorry for my lack of clarity. The bottom end of the luff cable or stay is usually connected by an articulating connector like a 'u' shaped screw shackle. Because it is free to move, then where ever the forces are directed, the stay cable points to. Since it is pulled tight, the vast majority of the force vectors are upwards.
- Will (Dragonfly)
Ah, now I follow. I guess that makes sense.
 
Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
I have a Selden bowsprit extended the max unsupported length of 35.5” to fly my asymmetrical spinnaker. I’d like to add a Code 0 but the Selden specs say I’d have to reduce the unsupported length to 17”. If I do that the furling line wouldn’t clear the pulpit. It seems this would be a common problem. How have others handled it?
The only solution I can see would be to reduce the foot and leech of the sail until the 35.5” sprit could handle it. Any thoughts? Thanks.
Reducing the area of the Code 0 isn't a solution to your dilemma, I'm afraid. The area of the sail is irrelevant when a big gust hits and the boat heels over hard. It's heeling that determines how big the loads on the rigging are, not the size of the sail.

All rigging on a boat must be engineered to withstand the loads generated by the maximum righting (and pitching) moment of the boat. When strong gust hits a small Code Zero making the boat heel, the bowsprit system has to withstand exactly the same force as it would with a weaker gust and a big Code Zero. Both situations make the boat heel to the same degrees. That means the force on the sails is the same in both situations.

Also. please remember that you have to look at the whole sprit system, not just the strength and diameter and wall thickness of the pole. The bowsprit system is linked to the keel via the bow ring, deck attachments and the deck structure. You must consider the loads on the mounting brackets and the strength of the deck at the attachment point.

The way I see it, you have two options here: buy a beefier sprit system (and attachment to the deck) that can handle the loads of a Code Zero, or modify the pulpit so you don't need a long bowsprit

If it were my choice, I'd modify the pulpit. Cut, move and reweld the top rail on the bow pulpit. so the furler's torsion cable can go in a straight line from mast to the approximate middle of the existing bowsprit. That's probably simpler than re-engineering the deck and bow sprit.

Pulpits that don't get in the way of flying furlers -- That's the solution used on all the recent-model boats. If you modify the bow pulpit, you can use a short bowsprit for your Code Zero with furler. Short bowsprit = lower forces on the hardware and deck. It's an elegant solution. No need for lots of excess engineering. Add a short bobstay from the Code Zero attachment point down to a Ubolt just above the water line and you're golden.

According to the specs published online, your Profurl SpinX 1.5 will do the job. But I'm a sailmaker, not a rigger, so please confirm that directly with the manufacturer.

JudyB
 
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Aug 1, 2011
3,972
Catalina 270 255 Wabamun. Welcome to the marina
Part of the issue is the interference caused by the existing fore stay. (furler or not). The extension of the sprit is necessary to get past the existing hardware, and in a mast head rig, the exit of the halyard is usually right behind the attachment of the fore stay, requiring a crane to extend the halyard forward.
Assuming the boat has a bow eye, the simplest solution is as stated, run a bobstay.
If the 0 is flown with the same hardware as the kite, then it's just the anti torsion line and top swivel that needs duplicated. Huge cost savings.
 
Nov 8, 2010
11,386
Beneteau First 36.7 & 260 Minneapolis MN & Bayfield WI
One other thing.

An asym sprit is usually set as far in front of the bow as practical. This allows:
1) Max sail area
2) Max projection to windward as the sprit pushes the tack windward of the mast when running
3) Max boat stability as the CE of the spin goes forward which stabilizes the plan

A sprit for a code sail needs none of these things, so it is only forward far enough to allow the furler to clear the pulpit and allow inside gybes. Having it shorter also reduces leverage forces on the sprit.

Sprits used for both sails will often have two attach points for these reasons.
 
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Jan 2, 2017
765
O'Day & Islander 322 & 37 Scottsdale, AZ & Owls Head, ME
Unfortunately shortening the sprit would bring the furler up against the pulpit.
At my technician's suggestion, we're trying reinforcing the Selden sprit by adding an inner tube. It should give it enough strength to handle the Code 0.
8A8B1326-AD02-4515-A001-4AD1B47BBE9C.jpeg
 
Dec 28, 2015
28
Beneteau Oceanis 31 Le Crouesty Brittany
Reinforcing the sprit will not reduce the lifting load produced by the code 0. The bobstay will definitely be helpful with the vertical force but will not be have enough effect on the sideway forces.
The following picture talks for itself.
111[1].jpg
 
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Jan 2, 2017
765
O'Day & Islander 322 & 37 Scottsdale, AZ & Owls Head, ME
I think it depends on how the bowsprit is secured, particularly at the bow. That photo seems to indicate that the sprit was secured only by screws into the deck.