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I purchased an open body turnbuckle to replace the closed body one on my forestay; unfortunately, the clevis pin on the lower end is larger than the one on the existing toggle (5/16 vs. 1/4 inch). Would it be alright to enlarge the hole in the forestay chainplate/tang that receives the clevis pin to 5/16, or am I asking for trouble doing this? Should I just find a toggle with the right size clevis?
Allen, it speaks well of you to be asking this question rather than just trying to make something fit. Toggles IME will have 2 pins (double toggle) or pin and hole (the kind you''re probably looking for) of the same dimension, e.g. 1/4". If the turnbuckle''s lower end fork has a 5/16" eye, you''ll be putting a pin smaller than intended in the eye, the result being point loading - not a good thing on a forestay, especially. All this might lead you to enlarge the chainplate hole that receives the toggle, but usually manufacturers don''t use more material than necessary, in which case doing this would be the worst of your choices. Without seeing the plate, I don''t see how any of us would know, for sure...but generally, this turns out to be a bad idea.
Can you return the turnbuckle and get one spec''d to the same dimension as the original?
which is apparently a reprint from "Good Old Boat")
Includes this useful rule of thumb: "The rule is that the amount of material below the hole must be equal to the diameter of the hole. Thus a 1/2 inch hole needs 1/2 inch of material between it and the edges of the tang."
Obviously, Jack, I should get one with a 1/4 pin if enlarging the hole would unduly weaken the integrity of the tang. It is true that in many cases, designers use only emough material as needed to meet a certain requirement (including a safety factor). Did they limit the width of the tang on my boat''s chain plate to the bare minimum necessary for the hole provided? I guess I''ll find out when I measure it!
This whole area of design is a fascinating one of course, and you can read books by Henry Petrosky to find out about stuff like failure and safety factors. Highly recommended if you''re not too busy fixing up your old boat!
First off, I would highly recommend against drilling out the chainplate. If a 1/4" pin was meant to go in there then I''d leave it at that. Putting a bushing in there could bring about more problems, ie. if the head on the pin is too small it could slip through or the cotter pin could bend through or the head of the pin could shear off or if you manage to do it right you then have a cluster of washers and bushings that will leap overboard at the first opportunity.
What brand of turnbuckle did you get and what was on there before? I ask this because most, if not all, turnbuckles have the same thread size as pin size (ie. 1/4 pin. 1/4-28 thread.. 5/16 pin. 5/16-24 thread). Thus in order to get a larger pin size the thread on the stud would also have to increase...... Unless the turnbuckle is toggle to toggle or eye to toggle, but then the size of the pin on the forestay wouldn''t match... What size wire is on the forestay? Sorry for the rambling but this is kind of an odd problem ... that might warrant a trip up the rig.
MIAHMOUSE,
Do I understand that you would rather see point loading on a clevis pin than a bronze bushing because you are afraid that someone is too stupid to see if the head of the clevis pin will go through the hole?
I believe the problem was that the hole in the chainplate or stem fitting was larger than the clevis pin for the new turnbuckle. In which case the pin won''t be able to slip through the bushing because it''s the same size as the holes in the turnbuckle toggle or fork and the bushing can''t go anywhere either because it is bigger than the holes in the turnbuckle toggle or fork.
Sorry,
After reading back through all the posts, I realized that the original problem was a turnbuckle with a bigger pin than the stem fitting. I had it backwards with my last message.
However, I know that if I were facing the same problem, I would still rather use some bronze bushing material cut carefully to the proper length, some ss washers if necessary and a heavy duty enough cotter pin or ring rather than use a small pin in a large hole.
In the worst case he might have to find a longer 1/4" clevis pin to allow room for a couple of washers.
Knothead
Not trying to start an argument here.....
Answering the first question, bushings over point loading without a doubt. But as you pointed out they would have to be two small bushings on either side of the chainplate with washers on the outside of the assembly all of which can be lost all too easily. Versus taking the incorrect turnbuckle back and getting the right size turnbuckle.
On the subject of stupidity of fellow sailors and riggers. Murphys law seems to run the show and I''ve seen and heard of more than my fare share of just plain stupid things. Some of these go back a few years, but for your amusement.
Daysailer capsized, owner was unable to right the boat, boat was towed in upside down breaking: stays, the mast in half, step of mast, tearing sails.
Wayward sailor attempting to raise mainsail strayed off course and into a day marker. Metal sign part of marker caught shroud of mizzen mast. Mast snapped at spreaders, "hopped" off mast step and began to flail around leaving notable marks in gelcoat and owners ego.
Owner of large sailboat with tall rig picks fight with short bridge. The bridge won.....
and just yesterday.
Man realizes that when he had a "professional" rigging shop install a furler they had apparently forgotten to a) put in a cotter pin at the bottom or b) bend said cotter pin. Result: Clevis eventually worked it''s way out while vessle was under sail. furler, forstay and sail began a rampage of swinging/banging/bending and twisting that took a total of 4 hours for the owner to get under control. Furler was destroyed, sail torn, boat and owner beat to hell.
And my personal favorite because I was on the boat.
Chartered two boats with a group of friends. On their boat was calamity after calamity due to improper or lack of maintenance. On the next to the last day of our week long excursion was a long sail down the bay. 13 kts of breeze on a tight reach, an absolutely beautiful day. The wind shifted slowly throughout the day till it was right on the bow. Wanting to make it to our set anchorage by nightfall we decided it might be a good idea to motor the rest of the way. Cranking up the engine we put her in gear and began to furl the sails. As the boat slowly came to a stop we soon realized there was a problem. A little investigation revealed that the shaft was still spinning, but there wasn''t anything in the water for it to spin. At first this appeared to be a minor setback. Until, as we tacked our way into the anchorage, the wind died. And then of course the coast guard came on the radio advising of a squall line moving south directly towards us with torrential downpours and winds up to 50kts. And half an hour later there it was, an eerie line of nastiness moving right towards us. Taking a moment to review our situation: we have no propeller, no wind (yet), we''re in a narrow channel and there''s a whole lot of wind and rain coming our way. I''m rambling way too much so I''ll just say that we got out of it unscathed and our companions on the other boat ended up towing us in to anchor (the wind died again after the squall past). We were in a potential world of crap all because someone forgot to put a locking pin on the driveshaft.
So to answer your original question, yes, there definitely are people that stupid out there. By taking nothing for granted you remove yourself from a lot of dangerous situations and the blame that can result from creating such situations....
With much contriteness I can only say that often I live up to my username. I let life get to me sometimes.
Your stories were all to believable. And if I think back I could probably remember similar experiences in my own history.
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