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Old 14-01-2015, 11:32   #16
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Re: Rod in cabin just aft of keel stepped mast

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Again I want to thank you all for the lesson here. Always good to add knowledge to the ole data base. Have a good one!
Hunt around. There was a whole thread on it previously.
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Old 14-01-2015, 12:36   #17
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Re: Rod in cabin just aft of keel stepped mast

From SailNet:

We have just bought a Coronado 41' (sloop), she needs some work and a good cleaning, we want to do this right so we found the original plans/owners manual for her, (Did I mention that we have had power boats in the past and this is the first sailboat that we have owned.) we have sereral people giving advice, some helpful some not, We have a question that no one seems to know the answer to. There is a threaded rod connected to the outer mast collar all the way down thru the headliner to the plate on the keel where the mast is seated (on the aft side of the mast), The only reference on the plans or in the owners manual, that could be a mention of it, is a notation on a blueprint that states "Panting rod". I cannot find any references as to what this is or what it is used for, can any one help out here? We plan on living aboard not racing.


Another comment:
Kittie, "Panting" is the term used to describe the breathing like movement that takes place in a ship's hull caused by pitching.
Very often extra beams called panting beams were fitted in older boats to counteract this movement, which is very destructive to the hull.
Your boat's manufacturer attempted to thwart the problem with the rod you have described.

Never knew what is was called, but "panting rod" sounds good. Maybe "anti-panting rod"?
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Old 14-01-2015, 13:48   #18
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Re: Rod in cabin just aft of keel stepped mast

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Originally Posted by George DuBose View Post
...Never knew what is was called, but "panting rod" sounds good. Maybe "anti-panting rod"?
Just what we need--more individuals making up their own names for boat parts, the names of which are well established.
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Old 14-01-2015, 14:23   #19
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Re: Rod in cabin just aft of keel stepped mast

Always called it a tie rod...

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Old 14-01-2015, 14:34   #20
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Re: Rod in cabin just aft of keel stepped mast

Tie rod =

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Old 14-01-2015, 15:48   #21
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Re: Rod in cabin just aft of keel stepped mast

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Tie rod =

Wise ass!
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Old 14-01-2015, 16:19   #22
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Re: Rod in cabin just aft of keel stepped mast



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Old 14-01-2015, 21:00   #23
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Re: Rod in cabin just aft of keel stepped mast

All good answers gentlemen. But what about the boat such as a older Ericson or S 2 where they attach a turnbuckle to the mast about 10-12 inches under the deck and attach the turnbuckle to the aft side of the deck at the partners and a pad eye to the mast. The whole premise here is to stop the mast from being shot through the keel when the rig is loaded. The panting rod and the turnbuckle stop the deck from being pushed up and the sides of the boat from sucking in which will raise the bulkheads off the bottom of the boat. Really simple physics which I know nothing about. It is action reaction. The mast loads the keel which if not stopped will push down on the keel causing the sides to come in and the deck to be pushed up, causing the bulkheads to become unattached off the bottom of the hull of the boat !!! See simple.
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Old 14-01-2015, 21:07   #24
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Re: Rod in cabin just aft of keel stepped mast

Quote:
But what about the boat such as a older Ericson or S 2 where they attach a turnbuckle to the mast about 10-12 inches under the deck and attach the turnbuckle to the aft side of the deck at the partners and a pad eye to the mast. The whole premise here is to stop the mast from being shot through the keel when the rig is loaded.
Umm, I don't think this is quite right, Rick. The keel structure is far stronger than the deck, and is what absorbs the down thrust generated by the rig. That short bit between deck and mast has the same job as the panting (tie) rod: to hold the deck down when it tries to rise due to halyard loads or the "squeeze" from the sides of the hull.

I think that it also satisfies the requirement set by some racing rules that a keel stepped mast must have some sort of restraint to prevent movement if the mast should break at or below the partners... but I'm a bit unclear about the latter.

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Old 14-01-2015, 21:18   #25
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Re: Rod in cabin just aft of keel stepped mast

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Originally Posted by Jim Cate View Post
I think that it also satisfies the requirement set by some racing rules that a keel stepped mast must have some sort of restraint to prevent movement if the mast should break at or below the partners... but I'm a bit unclear about the latter.
It does not, at least under the wording of the current rule, which requires that the heel of the mast be secured to the mast step or adjoining structure. It's to prevent the mast from jumping the step and becoming a swizzle stick and scrambling the cabin's occupants should the rig fail. However, a safety inspector would likely look at the turnbuckle arrangement, purse their lips, and 50/50 say it met the requirement since it effectively accomplishes the same thing.

As an aside, I like me a good panting rod. Makes a good handhold.
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Old 14-01-2015, 21:18   #26
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Re: Rod in cabin just aft of keel stepped mast

Jim until you have had the rod rigging pull the bulkheads off the bottom of a Nelson Merck 45 2 inches, 300 miles offshore on the way to Mexico in 40 knots of wind for 4 days, you will not understand what I just said. 90,000 miles in racing sailboats of all types and being involved with the brightest and most innovative fiberglass designers in the industry gives me the insight to know of what I speak. And the deck is supported heavily at the partners so the rod and below deck components can do what they do, which is support the mast and chain plates and keep everything where it should be under load. The rod and deck concerns are not required when the designers actually build full bulkheads that carry all of the chain plate loads from the mast step to the keel without even effecting the deck. Just saying !!!
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Old 14-01-2015, 21:22   #27
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Re: Rod in cabin just aft of keel stepped mast

Snow--sorry, if Henderson calls it a tie rod, that must be a suitable term.

Jim--good pointing out the running rigging loads imposed by turning blocks mounted to the deck.
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Old 14-01-2015, 21:35   #28
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Re: Rod in cabin just aft of keel stepped mast

This is the "panting" rod of our boat. The windex is just being stored while the mast is out of the boat. The rod runs from the collar to the mast step structure.
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Old 14-01-2015, 21:44   #29
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Re: Rod in cabin just aft of keel stepped mast

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Originally Posted by RickDelaune View Post
All good answers gentlemen. But what about the boat such as a older Ericson or S 2 where they attach a turnbuckle to the mast about 10-12 inches under the deck and attach the turnbuckle to the aft side of the deck at the partners and a pad eye to the mast. The whole premise here is to stop the mast from being shot through the keel when the rig is loaded. The panting rod and the turnbuckle stop the deck from being pushed up and the sides of the boat from sucking in which will raise the bulkheads off the bottom of the boat. Really simple physics which I know nothing about. It is action reaction. The mast loads the keel which if not stopped will push down on the keel causing the sides to come in and the deck to be pushed up, causing the bulkheads to become unattached off the bottom of the hull of the boat !!! See simple.
That's pretty much what everyone already said other than the "shot through the keel" bit. And I agree with Jim that the risk is not that the mast will be "shot through the keel". The risk is distortion of the hull, which needless to say will separate your bulkheads from the sole, or worse.

That turnbuckle attached to the partners is not going to keep the mast from driving down through the hull. The partners are free floating and unsupported. The turnbuckle supports the coachroof so that it can maintain it's lateral rigidity.

Maybe by saying "shot through the keel" you meant something different. I, and I think Jim, interpreted it to mean actually penetration for the heel of the mast through the hull.
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Old 14-01-2015, 22:16   #30
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Re: Rod in cabin just aft of keel stepped mast

Quote:
Originally Posted by RickDelaune View Post
Jim until you have had the rod rigging pull the bulkheads off the bottom of a Nelson Merck 45 2 inches, 300 miles offshore on the way to Mexico in 40 knots of wind for 4 days, you will not understand what I just said. 90,000 miles in racing sailboats of all types and being involved with the brightest and most innovative fiberglass designers in the industry gives me the insight to know of what I speak. And the deck is supported heavily at the partners so the rod and below deck components can do what they do, which is support the mast and chain plates and keep everything where it should be under load. The rod and deck concerns are not required when the designers actually build full bulkheads that carry all of the chain plate loads from the mast step to the keel without even effecting the deck. Just saying !!!
Well, Rick, your credentials are just fine, but you did say "The whole premise here is to stop the mast from being shot through the keel when the rig is loaded." Your example above does not address that statement as I see it. A panting rod of either type would (should) have prevented the bulkhead distress that you describe, and that situation, while disturbing, does not suggest the mast penetrating the keel step. Nor, IMO is the deck structure strong enough to absorb the downward thrust of the rig loads, and to prevent your hypothetical "shooting" of the mast. It is the keel structure that does that job on a keel stepped mast.

In general, some sort of athwartships stiffening of the hull in way of the chain plates is required. Bulkheads, ring frames, deck beams... there are lots of ways to accomplish this. If that is done well, the panting rod has only to absorb the loads from the halyard turning blocks, if any.

Cheers,

Jim
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