Cabin Top Traveller On Tritons

[jollyboat]

In attempting to keep up with the KAHOLEE refit that is taking place at NYR,I noticed that a cabin top traveller was being installed on KAHOLEE. This something that I have been interested in doing for a long time now and was wondering if anyone has done this and what the final sheeting arrangement is. I like the end boom sheeting for its advantages in both leverage and simplicity, but I dislike the main sheet having to "wipe" across the cockpit during tacks and jibs. Any suggestions are welcome.

[suntreader]

I've been thinking about this too for my Islander. It would be nice to get the main out from behind the cockpit and out of the way on the cabin top, but then the sheet is there too. That means I can't get to the main sheet from the wheel. Those of you who have moved the main to the cabin top, how often are you dashing between the helm and the main sheet?

Dave

[Tim]

I think for the amount the typical cruising sailor adjusts the main, a quick dash to and from the helm (if you have a wheel at the aft end of the cockpit) is no problem.

On a Triton, one is never too far away from the cabin top, meaning that the sheet is generally within fairly easy reach, if not quite as convenient as the stock location at the aft end of the cockpit.

I believe the plan on Kaholee is to lead the sheet from the traveler tackle forward along the boom and then aft along the port side of the coachroof, though the details won't coalesce till spring.

The only other Triton I've seen with the mid-boom sheeting arrangement was Bill Bell's Kialoa (now owned by John Wasielewski). His sheet ran forward along the boom and then aft to the cockpit to starboard.

[Tim]

I should add that although I don't use a mid-boom setup on my boat, I have used them rather extensively in the past. They work pretty well, and it can be nice to have all that gear truly out of the way. When possible, though, I always prefer end-boom sheeting.

[Figment]

New boom?

[Capn_Tom]

Is that astro turf I'm looking at?

[jollyboat]

All - Thank you for the insight on the Triton cabin top traveler and mid-boom sheeting position. This something that I am definitely going to follow through with - at least to the point where I might find what I feel would be a better main sheet running arrangement. I agree with Tim, in that in many respects, end boom sheeting has its obvious advantages but I find the behind the back sheeting, especially in exicuting jibes to be cumbersome. I would also like to investigate the use of 'bench backs' on the stern end of the cockpit benches (similar to those seen on some Concordia arrangements). This would allow me to lean back in comfort, steer with my foot as I usaully do,and trim the main with the sheet lead forward of my position. Thoughts?

[LazyGuy]

Bear with me while I voice an opinion. As an engineer, I see mid boom sheeting as a marginally acceptable alternative to a mid cockpit traveler on a high aspect ratio rig (with end of boom sheeting). Why would you want to interrupt the beautiful lines of the cabin with a traveler. Particularly when you put it on a bridge. Running the sheet forward along the boom then back to the cabin top is much cleaner leaving only the traveler behind you.

Also, be careful with mid boom sheeting and a loose footed main. The stresses are all at the clew and not distributed along the bolt rope. It is a sure fire way to break the boom on the first bad jibe over 15 kts.

[Figment]

Dennis, I'd think that most of the load is at the clew even with a captured foot. Look at any string-sail, there aren't any strings going to the foot.

This mid-boom sheeting is never a thing to be taken lightly, but I'd venture the opinion that it's particularly critical on a Triton. The main truly is the primary sail, and it's on a looooong boom.
The traveler on Kaholee looks like it's even farther forward than that on Kialoa. It looks like it's about 40% of the boom's distance from the gooseneck. Really, a bit farther forward and one might as well bag the traveler altogether and just install a grossly-oversized vang.

As much as I hate to say it, the Hunter approach makes a bit more sense. A super-engineered dodger frame with integral traveler.

Wow did I really just write that? This whole post-haulout depression syndrome is some scary stuff.

[LazyGuy]

Mike,

I guess I don't have much of an argument for the loose foot versus captured foot but mid-boom sheeting still seems like a bad idea for traditional low aspect ratio boats the leverage is all wrong. It's like lifting a 16# sledge by the end of the handle. It can be done but there are easier ways.

It doesn't help that I learned on an old traditional long boom boats with end of boom sheeting, I own one and race on two others. Legacy is the only high aspect, mid boom sheeting boat that I sail on. I find it awkward that Joan needs to stand in the companion way and brace herself to get any leverage on Legacy. So I am already partial to end of boom sheeting. I am also partial to tillers for the same reason.

[Tim]

I don't think anyone's ever called any aspect of a mid-boom sheeting arrangement to be anything more than a compromise at best, at least not with a straight face.

It's clear that end-boom sheeting is superior in terms of sail control, opposition of the greatest stresses, and boom strength. Nothing is optimal when you move the sheet forward, and no one's advocating that it's the best thing to do. That doesn't mean it isn't workable, if less than ideal. It all comes down to what one specific individual decides are the more important things in their specific case. Certainly it's not a change everyone would choose to make, or even consider making.

In this case, the owner made the choice based on specific needs, and related aspects of the required installation (sail, boom strength, etc.) are still under development and consideration. This change hasn't been made in a vacuum. Stresses on the dinky Triton boom are always a concern when upgrading any of the hardware--vangs, goosenecks, and sheeting. Modern adjustment hardware is a lot more powerful than the stuff from 1960.

The lesson here is that there is a cause and effect for every decision made when outfitting a boat. Know the pros and cons of each choice, and use that information to make the decision appropriate for your own requirements.

[keelbolts]

I would be wary of a loose-footed main with a mid-sheeted boom. With three point loads on it, in the right conditions, that boom is really going to want to fold. I once broke a substantial gaff that way.

[jollyboat]

All five fundamental load types act on booms at the various points of sail: tension, compression, shear, bending, and torsion with the most common being compression from the boom end into the mast and bending with the clew force causing upward tension on the on spar and the downward load applied with the main sheet. The foot of a main sail has very little load at all on any point of sail. A main sail with the foot connected, will not add any strength to the boom in handling the forces or loads placed upon it either by the sail or the attachment point of the main sheet. With that said I have decided that my issues with a forward lead position are greater than that of the main sheet's end boom arrangment. I am going to try other types of mainsheet l eadarrangments before making any larger changes.

[keelbolts]

I'm not an engineer, but my time in architecture, years ago, cause me to believe that spreading the load along the boom causes it to act differently than focusing the loads at three points. Invert the forces and think of it as a beam. Would you rather spread the load out along the beam or stack it all in the unsupported middle?

Having said that, the gaff I broke did have the weight of a sizeable main and boom hanging on it when it broke, so it might not apply here.

[jollyboat]

Jeff, I am not an engineer nor architect and so my capacity to make accurate comment as to the influence of load types and acceptable tolerances of construction techniques in buildings is limited at best. In regard to sails, thier construction and tolerances, with a focus on sailing vessels 50 feet and less I am more comfortable in relaying substantive information on the subject in that my profession as a sail maker and sail designer somewhat allows it. This is mentioned with all due respect and humility as I am not at all trying to toot my own horn. In as far as main sails or any sail for that matter that are connected at the foot to a spar - this done for sail control and has nothing to do with dispersing the load of sail throughout the length of the spar or supporting the spar. The spar supports the sail whether veritcal or horizontal. As I have mentioned, I am no longer going to change the end boom sheeting on my Triton, but I do plan on experimenting with a final forward sheeting application achieved through what is desribed by Harken as an Admiral's Cup 2:1 system. I will most likely include a fine tune adjustment as well.

[keelbolts]

If you are a sailmaker, you certainly know more about this than I do. I was just operating on my 'gut' anyway. Now, if I have sail questions, I know who to contact.