Which is more important, straight mast or balance shroud tension?

[Vtonian]

Bruce, I was using the 'Regular' model you show and realized immediately that it was necessary to be really careful how I applied it to get repeatable readings but was able to do that repeatedly, at least close enough to believe I wasn't dangerously overloading or under tensioning one. I was also skeptical about accuracy but allowing room for all the variables that might affect accuracy for any individual piece of cable, and that ultimately, it's going to be an eye/feel proof of the pudding anyway, it seemed like a pretty reasonable place to start for an indeterminate age rig with obvious issues and lots of room for improvement, especially for a novice.

One of my biggest concerns about this boat has been the potential corrosion around the base of the mast. What little I know about aluminum is that it's really strong, until it's not, when it very quickly becomes rubbish, sometimes without a lot of indication. I did clean and inspect that enough before tensioning to convince myself the mast has mostly a surface/paint issue but I had been concerned about whether tightening up the rigging might crush it. I've had corroded aluminum crumble in my hands and in fact, part of the pedestal base did just that on my last sail, going from a major crack in the flange to a pile of dust when I stepped on it one more time.

At the other end, I've also been concerned about the amount of rust staining around some of the stainless, notably the backstay chainplate. What little I know about stainless is, crevice corrosion can be disastrous and often the only indication might be that rust staining. Based on my oath to first, do no harm to this boat and second, sail it at least as much as I work on it, I didn't want to destroy something I might need to fulfill my sailing commitment this first season with her. But those issues will be stories for another day...

 

[bigd14]

I found this tuning guide useful when we had a masthead boat, it mostly repeats what has been said here already but may be helpful nonetheless. I found it very easy to adjust the rig on my E27 following this advice.

A Mast Tuning Guide - The Light Version | Ballenger Spar Systems

Mast tuning is simple if you remember a couple of basic principles. If you understand these principles, you can tune just about any mast.

www.ballengerspars.com

There are tuning guides for the 30+ fractional rig in the archives here. On this boat I have struggled to find the appropriate tension- too loose and the leeward stays slacken, which is advised against in the tuning guide, but adding a few more turns causes the head door to start binding which makes me nervous that I am over tensioning and bending the boat. It’s hard to know where to end up. I also can’t seem to get very much bend in the mast with backstay tension, so perhaps I haven’t done it quite right. I try to balance tension side to side by tapping the shrouds with a wrench like a guitar string and listening to the sound. When the tones roughly match I figure I am close, and then check to make sure everything is still in column. I often wonder if I should be more scientific about the whole process (eg a Loos gauge), but so far I have not gone there.

 

[Christian Williams]

The stainless steel used in yacht fittings typically rusts. It's probably 316, I have been told again and again. It is designed to be cleaned periodically, and there is no loss of strength.

Stress working, crevice corrosion and other issues of oxygen deprivation are something else. The rust shown in the photos can be removed immediately with household rust cleaners, although if you let it go that long it may take some doing. I put a few squirts of Bartender's Friend on the stanchion bases every wash, and the exterior chainplates forestay and backstay as necessary.

But it's true that rust deserves attention. On coated lifelines, say, or swaged stays, it can mean more. Rust around keelbolts, which is inevitable, suggests the bilge might be kept drier, so as to allow the exposed bolts to form their corrosion proofing. I attend to that regularly, for its psychological value, while the keel bolts grin up at me in amusement at my folly.

 

[Vtonian]

@bigd14, brilliant, that tuning g guide mentions the opposite effect on the mast of tensioning a shroud that crosses the tip of a spreader. I'd guess there's more math involved but the concept might help explain my conflicting tension/alignment results. Can't wait to get back and twiddle with this concept.

Also, I noticed my head door seems to have a will of its own, sometimes sticking, other times free. Hadn't gotten around to thinking that through but good to know I'm not alone and rig tune may affect it.

@CW, I feel a little more assured, thanks, will proceed with cleaning and set aside a bit of my worrying.

I was going to grab some BTF the other day and didnt because they didnt have the original dry powdered stuff. You mention a 'squirt' of it though so I'm assuming the liquid version is Ericson approved. Cleaning the stainless/stains is going to do so much for our morale!

 

[Loren Beach]

Cleaning the stainless/stains is going to do so much for our morale!

Revealing a little more
about my mental state.... but we do get regular comments on how shiny all of the SS deck parts are on our boat.

That's after I polished them out while they were off the boat for the 2021 re-fit. Buffing the SS parts is kind of a "zen" sort of work. Not at all exciting, but the result is really good for morale, mine.

 

[Vtonian]

Revealing a little more
about my mental state.... but we do get regular comments on how shiny all of the SS deck parts are on our boat.

That's after I polished them out while they were off the boat for the 2021 re-fit. Buffing the SS parts is kind of a "zen" sort of work. Not at all exciting, but the result is really good for morale, mine.

I get it. I'm personally not a spit and polish fiend, although I respect those who can/are, but I do like things to be ship shape and the rust is such an obvious sign of neglect, that bothers me a lot. Now that I'm finally able to start working on the important things, the appearance needs to level up as well. It's one thing to have the cabin full of tools instead of cushions and beverages, another for it to look like the Black Pearl rolling through the marina...

 

[Kenneth K]

I found this tuning guide useful when we had a masthead boat....

Nice post! Answers a question I've always wondered about:

"Make sure that the turnbuckles are lubricated with heavy lubricant to prevent galling and damage to the threads."

Sure, oil on the threads can attract dirt, but I suppose that can always be wiped off after tightening.

 

[bigd14]

I use Tef-Gel on the turnbuckle threads. It does attract some dirt but they have always turned smoothly when I needed them to.

 

[G Kiba]

Stainless steel can also pick up iron from the tools used on it. Most quality stainless steel parts are passivated with acid to create a protective oxide layer (per google). Sailcoat or Mclube works well on turnbuckles as well.

 

[Christian Williams]

And old PVC cowl vents? To stave off replacement, they can be painted with a rattle can of enamel. It sounds unlikely, but it works for a season or even two and makes them look new. That goes for plastic winch handle holsters, too, which discolor fast.

 

[Vtonian]

Stainless steel can also pick up iron from the tools used on it. Most quality stainless steel parts are passivated with acid to create a protective oxide layer (per google). Sailcoat or Mclube works well on turnbuckles as well.

Like the idea of a dry lube.

I shot Kroil on these the day before, nothing frozen when I went back. Seems pretty amazing penetrant and doesn't harm fiberglass.

 

[Neil Gallagher]

Hi Folks:

I'd like to reinitiate this thread, lots of good information here. My situation is related but a bit different. I worked with my trusted rigger and replaced all the shroud chainplate bolts (when went Garhaurer) on my 381 a couple of years ago, followed the conventional wisdom (I think) of tensioning the tie rods by hand then one additional turn with a wrench. The rigger then tensioned the shrouds to spec by feel and with a Lose gauge. Recently we replaced the uppers, same technique. I noticed the rig was not in column while sailing. A friend and I retuned the rig with the his Lose gauge to spec and now the head door is tight. Placing a level at the base of the port uppers I see some lift of the deck. I've checked the port bulkhead and associated bulkhead chainplates and all look fine. Since the chainplate bolts have been replaced how do I know how munch tension should be on the tie rods? I assume I should now back off the shroud tension and take up on tension on the tie rods but how much? Any suggestions would be much appreciated.

Neil Gallagher
SV Waypoint

 

[Christian Williams]

Placing a level at the base of the port uppers I see some lift of the deck.

We have the same boat. I can only say that I have no lifting of the deck and that the tie rods appear very taut. So I guess that means thatII would attempt to loosen the stays and tighten the tie rods a little.

I found the design of the stays to be sorta weird, given that the tie rods are not aligned with the force on the stays, and use the deck u-bolt fitting as a turning point--and that the huge cabin chainplates are fastened only to half-inch plywood.

The surveyor smiled. He said when you design a sailboat, you do what you have to do to make things work. Not perfect, but a common solution. Subsequently I have come to admire the design, which is quite apparent to the eye belowdecks in our model.

 

[Dave G.]

I have seen many keel stepped mast boats with deck tie downs to prevent the deck from lifting when rig is tightened. It's a rod with a turnbuckle that attaches to the deck collar and then down on the mast a foot or so. Snug it up and then tighten the shrouds. Most of the performance boats I've been on had 1 or 2 of these installed. Although this is usually to prevent the deck being lifted by halyards and sheets running through the mast base turning blocks. If it's tweaking from just shroud tension alone I would recheck the tightness of the tierods that go from the chainplate to the deck. This should be done with the boat in the water of course.

 

[Neil Gallagher]

Thanks Christian, Dave. The tierods are firm so do you think once the shrouds have been loosened take more turns on the tierods until the deck lift is gone then retention the shrouds? Sounds scary…..

 

[Dave G.]

The tierods are firm

Do you know what the shroud tension percentage was set to on your friends Loos gauge ? I never went more than 20% on the caps and 16-18% on the intermediates. The hard part is figuring out how tight the tierods should be with shroud tension. You may have to loosen the rig and start over with the tierods to be sure. For a check I would back off the shrouds a couple turns equally wait a while for the boat to settle and see the head door alignment is better. If it is and you know the rig tune was done right then you need to loosen the rig enough to reset the tierod tensions again. Snug them up and then 1 full turn.

 

[Dave G.]

I have come to admire the design, which is quite apparent to the eye belowdecks in our model.

And much more attractive than the Soverel 33 arrangement

 

[Christian Williams]

Yikes!

 

[Neil Gallagher]

Do you know what the shroud tension percentage was set to on your friends Loos gauge ? I never went more than 20% on the caps and 16-18% on the intermediates. The hard part is figuring out how tight the tierods should be with shroud tension. You may have to loosen the rig and start over with the tierods to be sure. For a check I would back off the shrouds a couple turns equally wait a while for the boat to settle and see the head door alignment is better. If it is and you know the rig tune was done right then you need to loosen the rig enough to reset the tierod tensions again. Snug them up and then 1 full turn.

Thanks Dave, I am headed to the boat this weekend and have those notes. I believe the caps are at about 15% and the others less than that. I’ll check it out and report back. What about the tension of the stay from the cabin roof to the mast step. Is there a tension measurement on that one?

 

[Loren Beach]

What about the tension of the stay from the cabin roof to the mast step. Is there a tension measurement on that one?

On our boat this is always quite snug. Never any reason to change it. Some boats, like the Valiant 40, have an SS tube running up adjacent to the rear of the spar to do this task. If the top of the cabin is staying stationary, that's the only thing I would look for.