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  #1  
Old 11-15-2003
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cal 34 - double headsail modification

I am considering modifying 1980 Cal 34 for double headsail, bowsprit. Any thoughts.
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Old 11-15-2003
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cal 34 - double headsail modification

Yes, Why in hell would you do that?

The Cal 34 is a nicely balanced design that would end up with a lee helm. There are few things more dangerous than a lee helm in a breeze. Then there are the structural issues. This would be a big job adding running backstays and reinforcing the deck and hull/deck joint for the thrust of the bowsprit and the hull for the loads from the bobstay bowsprit shrouds and runners. Then there is the increased pitching due to the weight being added forward. And this is supposed to do what for you?

Jeff
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Old 11-16-2003
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cal 34 - double headsail modification

I''m guessing but - is what you want to deal with here is providing for an effecient, easy to use low sail-area setup for offshore use in high winds? That would be provided by installing an inner forestay on which a small jib or storm jib can be set. IF that''s where you want to go, you''d need to get some one to engineer an attachment point and reinforcement for the inner stay''s foredeck connection.

If this ain''t it, then beats me...

Good luck.
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Old 11-16-2003
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cal 34 - double headsail modification

"I''m guessing but - is what you want to deal with here is providing for an effecient, easy to use low sail-area setup for offshore use in high winds?" That would be nice but that is not what he is descibing. He is describing and efficient sail plan that will be harder to use in light, moderate and heavier conditions. In a sail plan like the Cal 34 adding an jibstay (the inner most stay when there is also a headstay) on which a small jib can be set really will create an object that will in the way major league and will be too small to use in winds much below 30 or so knots and too big to be a good storm jib. If he goes the route he descibed or even if he goes the route you suggest on this particular model there is a lot more to engineer than the stay attachment.

Jeff
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cal 34 - double headsail modification

The primary purpose of an inner forestay is in fact to fly the storm jib whose use would of course be above 30 knots. Being in the way is not as issue as you don''t leave the inner forestay rigged, you keep it back at the mast unless you anticipate an immediate need to use it.

Hopefully tgeorgeson can clarify what problem he wants to solve, but a removeable inner forestay is an effective sail plan for a storm jib.
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Old 11-17-2003
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cal 34 - double headsail modification

Two points here, first of all in his original post tgeorgeson is talking about adding a bowsprit and moving the headstay to the end of the bowsprit and then having the jibstay run to the bow fitting. (Please read his post) This does not permit a removeable jibstay because you never want the primary support for the mast to be tacked to the end of a bowsprit.

The other part of this is that I strongly disagree that "a removeable inner forestay is an effective sail plan for a storm jib" on a boat of this size and sail plan configuration. With this rig and hull form the CE for the storm jib needs to remain quite far forward in order to avoid massive and perhaps uncontrollable weather helm. Also whatever else happens, in the kinds of conditions that would require a storm jib the forestay will need to be stripped of its headsail because a boat like the Cal 34 will take knockdowns off of the windage of the rolled up sail alone. At that point he is much better off using a strapped on storm jib than trying to rig a jibstay.

Jeff
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Old 11-17-2003
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cal 34 - double headsail modification

Perhaps we''ll hear again from tgeogeson as we''re both guessing what he meant (Please read his post).

I am surprised about your reservations about use of an inner forestay as this approach is frequently recommended (e.g http://www.sailnet.com/collections/articles/index.cfm?articleid=hancoc0011). I''m no expert on storm sails (we inherited our setup from the Prior Owner), but the experienced boats seem to get the storm jib off the forestay...Isn''t the risk of weather helm primarily determined from the sail area if any set aft the mast? I think that''s why we have a third reef.

From my perspective, being required to remove a genoa when use of a storm jib is required seems a formula for potential hurt.

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Old 11-18-2003
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cal 34 - double headsail modification

In high winds weather helm comes from a number of factors but primarily from heeling assymetry and from the dynamic balance between the mainsail and the jib, and the underwater elements generating lateral resistance. In a traditional boat designed to be a cutter, the jibstay (what you have been calling in the ''inner stay'') is tacked to the stemhead and the mast us further aft in the boat and so the center of effort is further aft as well. Similarly, the center of lateral resistance is also located further aft in order to be in balance with a center of effort located farther toward the stern than is typical for a sloop.

But also, as a traditional boat heels the underbody of a traditional hull form develops lesser assymetry when heeled. Shedding the sail on the headstay works on a traditional cutter because everything else is so far aft. The trade off is that traditional cutters were infamous for developing a lot of weather helm when sailed that way.

More modern boats like the Cal inherently develop weather helm when heeled. The key is to develop a dynamic balance and that would require keeping the center of effort pretty far forward.

The other item that you touch on is the furled up jib. In the kinds of winds where a storm jib and storm trisail make sense (or even a third reef makes sense) It is not unusual for a smallish boat (perhaps under 40 feet) to take a knock down simply under the windage of the rolled up sail. (Been there, done that, wore out the teeshirt) When you talk about those kinds of survival conditions you need to strip the roller furler or you are unable to even hove to without taking big knock downs. When you talk about a comparatively low stability boat with a comparatively tall and heavy rig like the Cal 34 this is certainly the case.

Jeff
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Last edited by Jeff_H; 08-08-2011 at 08:19 AM.
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Old 08-08-2011
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Really old thread I know .. But Jeff H , you saying a Cal34 rigged for heaving to is prone to knockdowns ?

A Cal 34 is best to lie ahull in a storm ?

sorry for old thread revival but I am looking for Cal 34 stuff ....
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Old 08-08-2011
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I am not saying that a Cal 34 rigged for heaving to is any more prone to a knockdown than any other racer-cruiser of that era. Nor am I saying that the best storm tactic for a Cal 34 is to lie ahull.

My comments were addressing my understanding of the question contained in the terse original post. As I read this post, the original poster was inquiring about adding a bowprit and trying to convert a Cal 34 to a cutter rig (modern definition). My comments were intended to say that Cal 34's are reasonably well balanced boats when flying the proper sail area for the conditions and that adding a bowprit and adding second jib tacked to that bowsprit would probably result in a lee helm, which is never a good idea for a boat intended for offshore use.

In the discussion, my understanding was that Sailingfool was suggesting adding an inner stay in order to fly a storm jib. I was commenting on that suggestion. My point was that in conditions which are heavy enough to require a storm jib you would probably also need to strip the furler of its headsail, because the weight aloft, and windage of a rolled up headsail is enough to knock down a small boat in those kinds of conditions. And also, I would be concerned that a storm jib flown from a jibstay located between the forestay and the mast would result in a lot of weather helm being located so far aft. It is the kind of modification which should not be made lightly since its position is so critical and the structural implications pretty extensive.

Although I admit that my comments were poorly written, my suggestion really was that on a boat the size of the Cal 34 and with a rig proportioned like a Cal 34, I would suggest using hanked-on headsails and having a hanked-on storm jib set on the forestay and a permanent track that runs to the deck for the storm trisail so that the storm trisail to be ready to raise at any time.

For the record, the Cal 34 is a boat that I actually like for coastal cruising but whose hull to deck joint I would consider their achilles heel for offshore use.

Jeff
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Last edited by Jeff_H; 08-08-2011 at 10:08 AM.
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