Cathedral or jumpers?

[12 metre]

Looking at a boat with an IOR style frac rig – i.e. replete with backstay, runners, and checks.

Is there any way of getting rid of the runners/checks while still maintaining forestay tension?  Short of going to a swept back rig that is.

Jumper stays are one solution, although they have their own set of issues.

I’ve seen Cathedral rigs mentioned but have never found a good description and from the few grainy distant photos I’ve found, it looks simply like an additional set of spreaders is added at the hounds and cap shrouds extended to the masthead.

Essentially converting a frac rig into MH in the transverse plane.

If that is they case, then I can see how it would add lateral support to the top mast and so useful for those going to MH kites on frac boats.  But I can’t see how it would add fore/aft support to the mast top to allow the backstay to control forestay tension.

Am I missing something – or are Cathedral rigs only used to add lateral support to the mast top?

If so, then it is quite possible that jumpers are the only practical solution.  IDK.

 

[SloopJonB]

I used to see cutters with what was called a "midstay" to tension the staysail stay. They ran from the staysail level back to about where B&R shrouds attach or maybe a bit farther aft. My old Fortune 30 cutter had them.

I've given some thought to trying it with the runners on my boat to see if they would tension the headstay enough.

 

[neuronz]

The answer pretty much depends on the spreader angle. Given the amount of lateral rigging you have now, I would assume you have inline spreaders. Then a cathedral rig is not going to help as it only gives sideways support. Jumpers can help if they have a bit of a spreader angle, but even then they only stiffen that section of the mast. 

The keys to low headstay sag are a stiff mast that does not bend under compression (which is what the runners and checkstays are originally added for) and a stiff (large cross section and/or high modulus) headstay.

 

[sailthebay26]

That's going to be alot of work and may still end up as a noodle.  Most of these rigs with all the aft rigging are needed due to the lack of fore/aft stiffness.  You may be able to tension the headstay with swept spreaders but they are going to need to be 20+ degrees in order to work.  This sweep will require need chain plate locations further aft and possibly additional structure in the boat to take the loads.  You may still end up with a bunch of midpanel deflection or compression failure of the mast butt due to the required tension.  As for the question about cathedral rigs usually the cap shroud (the larger stay) still goes to the headstay location and then a smaller stay is sent to the masthead.  In this system you tune the rig with the "jumper" loose and then add it last to control mast tip movement

 

[12 metre]

That's going to be alot of work and may still end up as a noodle.  Most of these rigs with all the aft rigging are needed due to the lack of fore/aft stiffness.  You may be able to tension the headstay with swept spreaders but they are going to need to be 20+ degrees in order to work.  This sweep will require need chain plate locations further aft and possibly additional structure in the boat to take the loads.  You may still end up with a bunch of midpanel deflection or compression failure of the mast butt due to the required tension.  As for the question about cathedral rigs usually the cap shroud (the larger stay) still goes to the headstay location and then a smaller stay is sent to the masthead.  In this system you tune the rig with the "jumper" loose and then add it last to control mast tip movement

Which was why I said "short of going to a swept back rig"  I've looked at that solution on another boat and it works if you also move the chain plates aft and outboard.  But yes, a lot of work and expense.

The answer pretty much depends on the spreader angle. Given the amount of lateral rigging you have now, I would assume you have inline spreaders. Then a cathedral rig is not going to help as it only gives sideways support. Jumpers can help if they have a bit of a spreader angle, but even then they only stiffen that section of the mast. 

The keys to low headstay sag are a stiff mast that does not bend under compression (which is what the runners and checkstays are originally added for) and a stiff (large cross section and/or high modulus) headstay.

Okay, that answers the question about fore/aft support of the cathedral rig, which was what I figured.  So a cathedral rig is out.  That pretty much leaves the jumper strut/stay solution.  Much like the rig of the classic Thunderbird below of the late 1950's.  And I've never heard anyone complain about their upwind ability.

Unless someone else has another idea.

 

[Leeroy Jenkins]

Cathedral rigs mentioned but have never found a good description and from the few grainy distant photos..........

That right there seems like a good reason not to try it.

 

[RantyDave]

Semi-related, I think...

Has anyone tried a really long masthead crane? We seem so in to big roaches these days, would it work to have a crane that extends about as far back as a spreader sticks out? Maybe double that?

 

[See Level]

On my old Dash 34 I added jumpers to go to a masthead kite.

They were almost as long as the upper spreaders and were swept forward, I think 7°. Ran 3/16" wire from head down to upper spreader root.

I had Spartech build them and Alan and Dick were both confident that they would help  forestay tension up to about 10/12 knots, which when adjusted loose, still allowed the main to unload the top in the puffs, it worked well.

Fractional spinnakers are stupid B)

 

[Pollination]

You cannot achieve proper headstay tension without , at the very least, runners originating at the horns and leading to the transom as close to centerline as possible. Then you must lead them to a winch so that you can wind them on hard. Especially on an old IOR boat that you are "looking" at. If the spreaders are swept back it works even better. 

This is if course if you want to race her. if not...you can make your cap shrouds very tight and your D-1's tight too.... of course you can have your headstay tight too....not sure why you want of get rid of all of the controls the yacht was designed with. You can also put a birdcage on your head and run around the boatyard asking others how you can achieve headstay tension without runners.(Please make sure that you where a proper pocket protector and lots of mulit colored pens)  

Swept back spreaders don't really work too well, you will have to apply a ton of permanent backstay tension anyway. 

 

[longy]

A lot will depend on the stiffness of the spar section above the hounds. Jumpers will add a LOT of compression. This question has to be raised with the spar builder.

 

[12 metre]

A lot will depend on the stiffness of the spar section above the hounds. Jumpers will add a LOT of compression. This question has to be raised with the spar builder.

You are of course correct - enough so for me to discard the whole idea.

This was kind of a spur of the moment thought and I hadn't sat down and analyzed the whole thing other than in general terms.

So thanks for allowing me to not waste any more time with the thought.

 

[Andy1]

A swept spreader configuration will require a stiffer section, gave higher compression and have higher initial shroud loads.  As a rule of thumb, 1 degree of sweep equals a 1% increase in the above although because it’s a circular equation this relationship will increase in an exponential rate.  22 degrees is the sweep in a maxi 72 so for this increase you’d expect a 28-30% increase in load capacity.

A good naval architect will provide definitive answers as all mast and deck hardware and structure will need to be checked to make sure the loads match.  Adapting an inline tube for this configuration is possible but you will likely end up with a much heavier solution and a virtual rebuild vs a new rig.

Hope this helps

 

[Remodel]

I hate to say this because I think they are ugly and overly complicated. Some form of B&R rig (https://en.wikipedia.org/wiki/B%26R_rig) will let you lose the backstay. The issues of course are compression and the fact that you have dial in a fair amount of pre-bend in order to establish headstay tension. It may also require a beefier mast section.

It's all about the number of boat bucks you want to invest with almost no chance of a return on that investment.

 

[SloopJonB]

It's all about the number of boat bucks you want to invest spend with almost no chance of a return on that investment expenditure.

Corrected.

 

[Remodel]

Corrected.

I stand, most humbly, corrected.

 

[12 metre]

I hate to say this because I think they are ugly and overly complicated. Some form of B&R rig (https://en.wikipedia.org/wiki/B%26R_rig) will let you lose the backstay. The issues of course are compression and the fact that you have dial in a fair amount of pre-bend in order to establish headstay tension. It may also require a beefier mast section.

It's all about the number of boat bucks you want to invest with almost no chance of a return on that investment.

Yes, B&R or swept back rig solves most of the issues, but as I alluded to in my OP, a sweptback rig is not part of the conversation.

I was just looking to see if there was an economical solution  that would reduce rig complexity without giving up too much performance.

I do not plan on racing in anything much above club level and want a simpler rig for short handed sailing and the acceptance that, at least locally it is near impossible to have a consistent crew.  Too many other things for people to do in their spare time it seems these days.

 

[MiddayGun]

View attachment 454589

There's a Contessa 33 at our club (the Rob Humphreys quick one, not the slow 32) which has a set of jumpers as you show above, but not extending as far down, as far as I can tell looking online none of the others have them. Its rig is quite typical of the time, narrow shroud base, about ten degrees of sweep & keel stepped. 
No runners. It wins a lot of stuff. 

Forestay isn't that tight, but I wouldn't class it as baggy. However that rig was never designed for runners, if your spreaders are inline then you're asking for trouble going without. Its hard to beat geometry. 

I've got a thread of me doing something similar to my boat, I moved to outboard chain plates and 21 degrees of sweep, its transformed the stability of the rig & the forestay tension, I also went to 7/8ths or maybe a touch over so the backstay has more impact on the headstay tension. Can still bend it pretty well if needed. 

Not cheap, but not mega expensive, especially if you can do basic glass & epoxy work. 
That said, not sure if I would do it again, I'd probably upsize the boat, but it was a fun project. 

 

[Livia]

Looking at a boat with an IOR style frac rig – i.e. replete with backstay, runners, and checks.

Is there any way of getting rid of the runners/checks while still maintaining forestay tension?  Short of going to a swept back rig that is.

Jumper stays are one solution, although they have their own set of issues.

I’ve seen Cathedral rigs mentioned but have never found a good description and from the few grainy distant photos I’ve found, it looks simply like an additional set of spreaders is added at the hounds and cap shrouds extended to the masthead.

Essentially converting a frac rig into MH in the transverse plane.

If that is they case, then I can see how it would add lateral support to the top mast and so useful for those going to MH kites on frac boats.  But I can’t see how it would add fore/aft support to the mast top to allow the backstay to control forestay tension.

Am I missing something – or are Cathedral rigs only used to add lateral support to the mast top?

If so, then it is quite possible that jumpers are the only practical solution.  IDK.

Having done this for real twice now , here the rules.

First a few things to learn

Forestay tension does not mean height, the right luff round means height. (Anyone who sailed 505s know this)

Be prepared to recut.

Jumpers or cathedral rigs will not be the answer with the existing section as it will compress the easily

so with out a new section you will need external sheeving on the side of the section

The minimum you need top this make work is 10 degree spreader but more the better.

Going to non overlapping rig is good as you can move the rig forward and on most boats you can move the chain plates back with enough packing to get at least 10 degrees

Going to non overtlapping rig will mean new sails so the luff round problem gets solved

Also if you move the chain plates to the side of the boat even better as rig load decrease

As for the top mast, usually it is never stiff enough fore and aft so be prepared to cut it down to a suitable length or just put a new one on.

Yes you will lose a little main area but you are working in a tight budget.

New rigs also are really very cheap given how long they last nad this is the best option.

but if not it is a number of changes that make it work.

Don’t forget the change the luff round

 

[Livia]

Oh, and Hicko put a alloy Sydney 38 rig in a 1983 Farr 43 and won a Hobart.

We dropped a rig on the hard stand (yep really) and did not replace new for old but used the opportunity to get a new section, move the chain plates by packing, raise the forestay height to get a shorter top mast.

Sure worked for us.