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Old 10-07-2011, 10:37   #16
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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Originally Posted by daddle View Post
Generally bronze turnbuckles are the GOOD ones. SS being the cheap ones that gall and jamb.

If you stick with turnbuckles from a marine catalog and don't screw around with non-standard pin and wire sizes you can assume it's already been worked out. That is, if you have 1/2" screws on the wire a like sized turnbuckle body in a rigging catalog will be fine.
The point of screwing around with the pins is that most of the turnbuckles are gone and there is likely to be more than one size. The turnbuckles that are there may or may not be OEM and if they are not then he is depending on whoever did the rerigging to have sized them correctly.

If they choose to match what is there and it is undersized then they run a greater risk of failure. If the existing is oversized they waste money (scouts are not know for having a lot of extra cash) on the oversized turnbuckles and they don't last quite as long anyway because there is a mismatch between hole size and pin size so wear is slightly accelerated.

Once you have the largest pin size that will work in the wire terminal you can work backward in a catalog to determine the size turnbuckle you need, then pick the strongest of all those in that size, bronze or SS or whatever.

Messing around with pin sizes has the advantage of maximizing strength, minimizing cost and correcting any sizing errors that may have been made in the past.

For what it's worth I would replace all the turnbuckles, if they are OEM on a Columbia 36 then they are 38-42yr old. I would keep the ones you got for spares.
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Old 10-07-2011, 11:41   #17
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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Type 316 is slightly weaker than 304.


Thanks GordMay! Pointing out the difference tween 316 and 304, and your emphasis on the word 'approximate' clears up what I found online. I'm adding those gems to my rigging notes.

Just returned from marina. They have roller furling foil as a headstay - no turnbuckle needed. They will use the old bronze turnbuckle on the back stay.

Their shrouds are 1/4" diameter and the breaking specs for both 316 and 304, times 20% to get Safe Working Load, IIRC, comes in at a range of about 1450# to 1680# (I left the paperwork with them) for all the different data I found, and calculating every way we could.

The Safe Working Load factory spec on their turnbuckle (linked above) is 1800#, so the units they have should work fine strength wise, assuming they are up to posted factory specs.

The only issue I could think to raise is that the jaw-to-jaw terminals on the turnbuckles are not toggled to allow biaxial flexing and so (guessing here) there might eventually be an issue with embrittlement by work-hardening if the flexing strain is not relieved through toggles. But that's out of my experience level...
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Old 10-07-2011, 11:55   #18
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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...he is depending on whoever did the rerigging to have sized them correctly. If they choose to match what is there and it is undersized then they run a greater risk of failure. <many good points snipped for clarity>...For what it's worth I would replace all the turnbuckles, if they are OEM on a Columbia 36 then they are 38-42yr old. I would keep the ones you got for spares.

Thanks much Adelie - many good points, well presented, and very educational for me. I guess they will rig with what they have, mostly motor the boat the 120 miles home (nearly new Yanmar 3), then take it from there, conveniently in their home port, where it all will be so much easier than essentially working a second job 3 hours away from home.

AIUI, the boat was rigged and sailing for awhile on its current rig, not counting the missing turnbuckles. So any added new, sized to the existing shroud wire size, should be OK until they can acertain the most correct specs.

Have sent them the link to this thread and will re-emphasize that they consider your points before using the rig very hard or very much.
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Old 10-07-2011, 12:59   #19
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

G'Day all,

The advice about matching pin sizes is good. This both gives you a good idea about the original sizing and prevents the serious difficulties afforded by mismatching the diameters.

But, one thing to consider is that the turnbuckles (rigging screws, bottle screws) shown in your link are pretty low quality. They are described as being cast, rather than either forged or machined from bar stock, both of which are means used by the better suppliers. I would view them as short term substitutes at best, especially as
they are very likely sourced from China at a low cost... not the best pedigree for reliability.

Finally, while Dyneema lashings with deadeyes sounds great, and is used by a few avant guard folks, mating them to existing shrouds and chainplates would be awkward at best, and would cost more than replacing the hardware. Then there is the issue of getting them tensioned correctly and maintaining them as they creep over time... not something to leave in the hands of volunteers and scouts IMO.

Meanwhile, good onya for your participation, and good on the scouts for continuing this good tradition.

Cheers,

Jim
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Old 10-07-2011, 18:29   #20
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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G'Day all,

The advice about matching pin sizes is good. This both gives you a good idea about the original sizing and prevents the serious difficulties afforded by mismatching the diameters.

But, one thing to consider is that the turnbuckles (rigging screws, bottle screws) shown in your link are pretty low quality. They are described as being cast, rather than either forged or machined from bar stock, both of which are means used by the better suppliers. I would view them as short term substitutes at best, especially as
they are very likely sourced from China at a low cost... not the best pedigree for reliability.

Finally, while Dyneema lashings with deadeyes sounds great, and is used by a few avant guard folks, mating them to existing shrouds and chainplates would be awkward at best, and would cost more than replacing the hardware. Then there is the issue of getting them tensioned correctly and maintaining them as they creep over time... not something to leave in the hands of volunteers and scouts IMO.

Meanwhile, good onya for your participation, and good on the scouts for continuing this good tradition.

Cheers,

Jim
Not hard if you are creative and why not scouts? They SHOULD be as disciplined as anyone (the whole point of scouting) and they SHOULDN'T be sailing through major storms....
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Old 10-07-2011, 19:20   #21
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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Not hard if you are creative and why not scouts? They SHOULD be as disciplined as anyone (the whole point of scouting) and they SHOULDN'T be sailing through major storms....
Discipline is good, but does not replace knowledge and experience. Then too, scouts tend to come and go... not the best environment for crucial maintenance.

And "not hard if you are creative"?? Do you speak from experience in mating old wire shrouds to existing chainplates with lashings? The appropriate hardware isn't cheap, it will be difficult to fit in the existing gap 'twixt shroud terminal and chainplate, and will require skilled installation. If you think otherwise, perhaps consulting with the folks at Colligo, who actually do these things and who have developed the systems would change your mind.

Remember, you are talking about sending someone else's kids out there in this boat. Sure, they "SHOULDN'T be sailing through major storms" but as you have noted in other threads, **** happens at sea. I think that they should have proven rigging to help them along their way.

YMMV.

Jim
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Old 11-07-2011, 10:53   #22
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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Originally Posted by Jim Cate View Post
Discipline is good, but does not replace knowledge and experience. Then too, scouts tend to come and go... not the best environment for crucial maintenance.

And "not hard if you are creative"?? Do you speak from experience in mating old wire shrouds to existing chainplates with lashings? The appropriate hardware isn't cheap, it will be difficult to fit in the existing gap 'twixt shroud terminal and chainplate, and will require skilled installation. If you think otherwise, perhaps consulting with the folks at Colligo, who actually do these things and who have developed the systems would change your mind.

Remember, you are talking about sending someone else's kids out there in this boat. Sure, they "SHOULDN'T be sailing through major storms" but as you have noted in other threads, **** happens at sea. I think that they should have proven rigging to help them along their way.

YMMV.

Jim
Building future leaders is tough and isn't safe by the very nature of scouting...otherwise they would camp in Mariott hotels...

Look to any third world fishing fleet and tell me how hard it is to do some simple rigging for basic day sailing or overnighting because Sea Scouts rarely sail around the world...not knowing what's there it's hard but a couple end fittings, shackles and nylon line could work. Seen it done....not yachtie...but that's not what's important.

Plus they aren't "someone" else's kids...I was a leader for my own kids for many years and Scouting was getting so soft I couldn't stand it. Future leaders of America??? Hardly...as the parents were woosies and that's what they were teaching their kids.

Doo Doo happens only when you aren't planning or prepared for it....Basic rigging failure can happen to anyone and most production swage fittings fail without warning...a set of lashed eyes is easier to inspect by novices any day.
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Old 11-07-2011, 16:12   #23
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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Building future leaders is tough and isn't safe by the very nature of scouting...otherwise they would camp in Mariott hotels...

Look to any third world fishing fleet and tell me how hard it is to do some simple rigging for basic day sailing or overnighting because Sea Scouts rarely sail around the world...not knowing what's there it's hard but a couple end fittings, shackles and nylon line could work. Seen it done....not yachtie...but that's not what's important.

Plus they aren't "someone" else's kids...I was a leader for my own kids for many years and Scouting was getting so soft I couldn't stand it. Future leaders of America??? Hardly...as the parents were woosies and that's what they were teaching their kids.

Doo Doo happens only when you aren't planning or prepared for it....Basic rigging failure can happen to anyone and most production swage fittings fail without warning...a set of lashed eyes is easier to inspect by novices any day.
Somehow I don't think that the analogy between third world fishing boats and a Columbia 36 holds up. Few of the many such boats that I have encountered have a sailing rig at all, and none that I recall have had a tall Marconi sail plan. What works to hold up a simple cargo boom or trawling rig won't necessarily work for the Columbia.

And they are too "someone else's kids" in this case. You, the scout leader for your kids are not going to be there on that boat with those kids... whoever they turn out to be. I think that when advising someone here on CF, a cavalier attitude about the toughness of "building future leaders" which leads to suggesting that a "couple of end fittings, shackles and nylon line" are an adequate substitute for proper rigging is rather poor form.


Cheers,
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Old 11-07-2011, 16:40   #24
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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Somehow I don't think that the analogy between third world fishing boats and a Columbia 36 holds up. Few of the many such boats that I have encountered have a sailing rig at all, and none that I recall have had a tall Marconi sail plan. What works to hold up a simple cargo boom or trawling rig won't necessarily work for the Columbia.

And they are too "someone else's kids" in this case. You, the scout leader for your kids are not going to be there on that boat with those kids... whoever they turn out to be. I think that when advising someone here on CF, a cavalier attitude about the toughness of "building future leaders" which leads to suggesting that a "couple of end fittings, shackles and nylon line" are an adequate substitute for proper rigging is rather poor form.


Cheers,
Everyone has an opinion and that's what these forums are all about...poor form???....suggesting that there are no other possibilities or limiting ones that follow your line of thinking ...well I won't say it...you're entitled to your opinion.

And there are plenty of third world rigging ideas that with first world tools/parts that would most certainly work...as I said...a little creativity is all that is needed.
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Old 11-07-2011, 17:04   #25
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

All things being equal stainless is stronger than bronze. Credible suppliers will give working and breaking loads for the fittings they supply. It is critically important for safety that the fittings have a safety margin higher than the anticipated load being placed on it by your wire.

BOSUN SUPPLIES - Stainless Steel Anchors Deck Hardware Chain Shackles Hooks Clips Titanium FORCE 5 Rigging Fasteners Tools Suncor Microstar Knowledge Information wire rope
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Old 11-07-2011, 18:57   #26
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

A general rule of thumb is that the turnbuckle size should be 2X the wire size, ie 1/2" turnbuckle on 1/4" wire. Look up the strengths of the wire, Gord May has listed them. Look up the strengths of the turnbuckles you intend to buy to verify this.

Bronze is not necessarily weaker than stainless. Bronze is a generic term for a wide variety of alloys. High strength bronzes can be stronger than 304 or 316 stainless. And weaker bronze alloys are weaker.
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Old 11-07-2011, 19:05   #27
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

At least in the maritime industry, the Safe Working Load is a ratio of the Breaking Strain. The ratio used is determined by the application. Shock loading tends to require a more conservative ratio.
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Old 12-07-2011, 10:22   #28
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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...And there are plenty of third world rigging ideas that with first world tools/parts that would most certainly work...as I said...a little creativity is all that is needed.

I'm with you on this - joining a piece of 1/4" wire rope to a chain plate, be it on a 39' Columbia, a home-built plywood catamaran, or a third world fishing boat, need not be rocket science. A shackle at each terminus allows the lashing. 1/4" wire rope has a breaking strength of +/- 7300#.

Dacron 1/4" braid has a breaking strength of ~1900#. Four and one half full turns, ending at the opposite shackle from the starting shackle, spreads the load over 9 pieces of line, for an ideal combined breaking strength of 17,100#, minus the reduction for knots and kinking it over the shackles. 7300#/9 = 811# carried per line at the breaking strength of the wire rope. This accommodates the reduction for knots and kinking in the line buy reducing the ultimate loading by 57% of breaking strength (811/1900=43%).

At the working load limit of 20% breaking strength of the wire rope, say 1460#, each of the 9 lashing elements carries only 162#, for a line with a breaking strength of 1900#. This relatively light loading helps prevent the chafe which is likely more of a factor than ultimate tensile strength of the lashing.

I have used these types of lashings on an old salvaged Wharram cat with no problem whatsoever. Regular unlash/relash inspections for chafe showed almost none, certainly not anything that suggested sudden failure from chafe was even remotely likely. IIRC, the line never needed replaced until UV deterioration became a factor, over a period of years.

Perhaps my most recurring doubt about the security of the lashings was that any nasty little vandal vermin with a pocket knife could drop my rig in moments...

Reading about, calculating, self-making and using those lashings was likely far more educational and satisfying than any shiny, high-tech, store-bought, plug-n-play solution (usually magically provided with "Daddy's money", in the case of kids)...
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Old 12-07-2011, 10:58   #29
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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I'm with you on this - joining a piece of 1/4" wire rope to a chain plate, be it on a 39' Columbia, a home-built plywood catamaran, or a third world fishing boat, need not be rocket science. A shackle at each terminus allows the lashing. 1/4" wire rope has a breaking strength of +/- 7300#.

Dacron 1/4" braid has a breaking strength of ~1900#. Four and one half full turns, ending at the opposite shackle from the starting shackle, spreads the load over 9 pieces of line, for an ideal combined breaking strength of 17,100#, minus the reduction for knots and kinking it over the shackles. 7300#/9 = 811# carried per line at the breaking strength of the wire rope. This accommodates the reduction for knots and kinking in the line buy reducing the ultimate loading by 57% of breaking strength (811/1900=43%).

At the working load limit of 20% breaking strength of the wire rope, say 1460#, each of the 9 lashing elements carries only 162#, for a line with a breaking strength of 1900#. This relatively light loading helps prevent the chafe which is likely more of a factor than ultimate tensile strength of the lashing.

I have used these types of lashings on an old salvaged Wharram cat with no problem whatsoever. Regular unlash/relash inspections for chafe showed almost none, certainly not anything that suggested sudden failure from chafe was even remotely likely. IIRC, the line never needed replaced until UV deterioration became a factor, over a period of years.

Perhaps my most recurring doubt about the security of the lashings was that any nasty little vandal vermin with a pocket knife could drop my rig in moments...

Reading about, calculating, self-making and using those lashings was likely far more educational and satisfying than any shiny, high-tech, store-bought, plug-n-play solution (usually magically provided with "Daddy's money", in the case of kids)...
Whimsy, I certainly agree that the lashing you propose is adequately strong to hold up the mast in static conditions. I am not so sure that a bunch of sea scouts and their volunteer mentors will find it easy to step the mast and then tune it properly for a seagoing delivery trip using such a setup, especially if there are time constraints on that voyage.

In your OP, you were asking about the suitability of certain rigging screws for the application, and I think that you have received reasonable responses to that question. That the volunteers needed to ask the question suggests to me that they are not well versed in rigging issues, and so for them an improvised "third world" solution might not be appropriate, especially with other peoples youngsters on board.

Finally, IMO rigging techniques that are applicable to Wharram cats do not necessarily translate to the subject Columbia. Your opinion and experience may differ.

Cheers,

Jim
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Old 12-07-2011, 11:57   #30
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Re: Sea Scouts Seek Advice On 1/2" SS Turnbuckles

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I certainly agree that the lashing you propose is adequately strong to hold up the mast in static conditions.

The reality is, despite what anyone, from the comfort of their keyboard, speculates will or might happen, I actually used lashings of this type to hold up a mast in very dynamic conditions, in storm and calm, for years, with NO problems whatsoever.
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I am not so sure that a bunch of sea scouts and their volunteer mentors will find it easy to step the mast and then tune it properly for a seagoing delivery trip using such a setup...

That's a moot point. The Sea Scouts have already stepped the mast and installed the turnbuckles they had based on the wire rope WLL being less than turnbuckle WLL. Seems to make sense and I doubt they will have problems with them. The boat is launched, the diesel fuel pump issue resolved, and things put relatively ship-shape. I speculate that lashings would have worked fine for them too, although I'm glad they have the SS gear. "Finding it easy" is probably not why they left the comfort of their homes to sail in boats - you maybe underestimate the resourcefulness, ability and experience of some of these individuals.
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...IMO rigging techniques that are applicable to Wharram cats do not necessarily translate to the subject Columbia.

Unless anyone can provide evidence to the contrary, and I welcome all comments, when connecting a 1/4" SS wire rope stay or shroud to a SS chain plate on a sailboat via an adjustable device like a turnbuckle or lashing, the defining parameters of the connecting device requirement are the wire rope WLL and the chain plate WLL, not the boat brand or type.
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