Mast pulled from deck

Hermit Scott · Jun 23, 2009

Do you have any pictures? It helps when these guys give advice.

sailingdog · Jun 23, 2009

Do you mean the backstay broke??? I've never heard of a stern stay.

Also, what is the metal receiver you're talking about? Is it the mast step, where the base of the mast sits? Is it the aft chain plate for the back stay??

Using the proper terminology helps a lot when describing things. Photos help too.

In either case, the hardware should probably be through-bolted rather than attached with screws. Through bolting with a decent backing plate will be far stronger than screwing anything to the deck, especially on a fiberglass boat, since fiberglass is relatively brittle and a poor holding medium for screws.

Also, is the metal receiver bent or twisted? If so, you'll have to get it bent back into the proper shape before going ahead with the repair.

Joseph Shirley · Jun 23, 2009

Justin; It's hard to picture what you're describing. The backstay normally pulls the mast down and back, and when it parts, the normal reaction for the mast would be to move forward at the head. Lower after shrouds and uppers would resist the mast from going completely forward or up, so the pulling of the receiver up would seem completely foreign to me. Do you mean the mast step?

Did you part the backstay while trying to raise the mast with the backstay, and before your aft lowers were in place?

Hermit is correct that pictures would help, but if for some reason you can't get them, you will have to make what you mean much clearer.

Good Luck,

Joe S

Ross · Jun 23, 2009

I'm with the rest of the gang. I could tell you that you need a hexical jack shaft to make the repairs but that doesn't exist either. Too many pronouns and not enough proper names.

sailingdog · Jun 23, 2009

My guess is that the OP is talking about a mast step, which goes up in to the base of the mast. If the backstay let go, the mast would be pulled forward, by the forestay, and it could lever the mast step forward and pry it from the deck, using the mast as a very, very long lever. If that is what happened, he's very, very lucky that is all that happened. There could have been a lot more damage.

Ross · Jun 23, 2009

My mast step is little more than a shallow dish. About an 1.5 inches high and fits inside the base of the mast . But it is a loose fit, no better than a pot lid. More designed to prevent the base of the mast from being knocked sideways than to provide any vertical support.

Ron20324 · Jun 23, 2009

Justin, I hope you'll overlook those who feel they need to chastize you and then not even make mention of your actual question. They know what you meant, but yes, since you are a boat owner it would help if you knew the proper nomenclature for things nautical. Get a West Marine catalog and look thru it once in a while.

The MAST STEP is secured mildly by screws whose purpose is to stop the sideways movement of the step, not hold it from vertical movement. In a way, they are like a zinc- designed to sacrifice themselves so that more importannt equipment may survive. (If you don't know what a zinc is, look it up - don't ask.) If the mast falls there is a tremendous amount of leverage force to pull those screws out, and if there were thru-bolts, you may just end up with holes down into the cabin.

If there is some deck area that has the same glass layup as where the original holes are, then redrill holes for the new location. I would think the entire area under the step is solid glass. An option would be to drill out the original holes, fille with epoxy, redrill for the previous size srews (but get new screws.) You would want to fill the old holes anyway.

sailingdog · Jun 23, 2009

Mine is a three-sided box that the mast step slides into. Two pins are used to prevent the mast from leaving the step once it is up.

Ross said:
My mast step is little more than a shallow dish. About an 1.5 inches high and fits inside the base of the mast . But it is a loose fit, no better than a pot lid. More designed to prevent the base of the mast from being knocked sideways than to provide any vertical support.

Allan12210 · Jun 23, 2009

Justin,

I think Ron's post was the most helpful. (Kudos to his patience.) I also understand that the nautical terminology used up in the Maritimes is different from ours, but perfectly understandable and equally correct.

If your mast step is attached to the mast as to allow it to hinge forward (tabernacle), I could see how it bent up from the deck. It probably should be removed from the mast base and checked for straightness. If it is not cast aluminum, maybe it can be bent back flat. As Ron says, the original screw holes should be filled back in with a mixture of epoxy and thickener like West Systems microballoons. Then you can either re drill in the same location or if the step is big enough, drill adjacent and reattach to the deck. If you are really lucky, there could be an aluminum plate under the deck that you can tap and use a machine screw on. Put plenty of sealant on the screws so no water can get into the core.

If you are from St. John, NB, I was there in September and was very impressed with the reversing rapids. With a 50 foot tidal range, I guess you plan accordingly.

Good Luck,

Allan

sailingdog · Jun 23, 2009

I'd point out that it is difficult to address a question, when the question is so poorly written as to be almost impossible to discern the original poster's intent. While I did take a wild guess, it isn't necessarily correct.

Ron20324 said:
Justin, I hope you'll overlook those who feel they need to chastize you and then not even make mention of your actual question. They know what you meant, but yes, since you are a boat owner it would help if you knew the proper nomenclature for things nautical. Get a West Marine catalog and look thru it once in a while.

Hermit Scott · Jun 23, 2009

Stern stay=backstay
receiver ...for the mast=mast step
79 mirage 26= circa 1979 mirage 26' sailboat
new to these forums=take it easy on the guy

no name · Jun 23, 2009

yea whwat he said

after my narzle-bart separated from the hookinob I got me a book.

alexco38 · Jun 24, 2009

Mirage

I raced on a similar boat a few years back. It has a U shape tabernacle with a thru bolt for the mast in the front. I suppose if you have a gin pole, you can winch the mast up and step it without a crane. Unfortunately some people also put a thru bolt on the back side. That might explain the lift up.

As I can recall, the tabernacle is made of cast aluminium thus un-bendible. He can try but I think it will break. Having said that, you can find someone in the area that does sand-casting and make a new one. If you are handy you can make a plywood model and have a new one made. The design is not complex.

Alternately, you can find a machine shop and weld a aluminium or stainless steel plates together for cheaper price. It is just a U shape thing anyway. BTW, if he has it thru bolted to the deck, the deck would have been pulled apart. The screw is actually a good thing in this case.

bffatcat · Jun 24, 2009

mast step trouble and old rigging problems

Most 70`s boats with deck stepped masts have a cast aluminum shoe to hold the mast in place. If during the mishap the cast aluminum got bent you probably will not be able to straighted it out. Cast Aluminum is brittle and dosent take kindly to straightening. If you need a new mast step go to a machine shop with the old one and get a duplicate made out of stainless steel. If you cant get stainless where you are you can probably use galvanized. Please what ever you do DO NOT use plywood for a mast step. Rain water will get in and rot the wooden step.

Also: You mentioned your back stay let go did the wire part from fatigue? Is the chain plate
loose? Is the rest of your standing rigging 70`s vintage? If so it needs replacing in a salt
water setting. Just some stuff to think about to avoid more failures.

Ross · Jun 24, 2009

Re: mast step trouble and old rigging problems

If he can find a shop with CNC machines they will be able to duplicate the old one with ease. Machining it from 6061 aluminum would be ideal.

RichH · Jun 24, 2009

I know that the famous designer Robert Perry designed most of the larger Mirage line of sailboats.
Dont know about the 26, but he definitely did the 27 (and larger) and I would be suspicious that the 26 had the same typical Perry designed deck stepped (FLANGED AND THROUGH-BOLTED) mast arrangement (to keep parts inventory simple). Perry's deck stepped arrangements are NOT the typical 'slip into a shoe' arrangment and use hefty 'through bolts' onto welded flanges on both the 'shoe' and the top of the 'inside the boat' compression post - makes a deck stepped mast just as strong as a keel stepped mast.

See if this is 'close': The mast butt/end fits into a large aluminum casting (mast shoe) and is further connected to a large stainless steel plate that has 4 LARGE bolts at each 'corner' of the plate - the plate is *under* the shoe but is on TOP of the 'roof'. These large bolts then connect through the 'coach roof' (rooftop) and connect to another plate inside the boat and are welded onto the compression post inside the boat ????

If so, youve probably bent the plate when the bolting broke, and you 'may' have also bent the compression post. Rx is to remove the mast, 'straighten' or have a new plate made (or repaired) if it actually is 'bent', get new through-bolts, generously SEAL the bolts/plate and bottom of the 'shoe' with caulk, ... and reinstall. If the compression post is now also bent (use a straight edge to check), you should also repair (straighten or replace) this too. When reassembling, the IMPORTANT item for consideration is that the assembly is FULLY SEALED so that water doesnt leak into the 'roof' of the boat, thus starting it to ROT. The rot growing in the wooden core between the upper fiberglass and the fiberglass that is on the inside (ceiling).

Is this the arrangement that you see? how about a digital pic if you are unsure?

Ron20324 · Jun 24, 2009

Guys, I have to look at this thread and chuckle- if not laugh out loud. There are 3 or 4 replies that tell what the mast steps are like on THEIR boats.... Though the original post does not say the mast step was even damaged, we have repilies to send him to welding shops, machine shops, forging/casting shops, fabricators.... Although inquiring minds want to know, it was not particularly important as to what happen to his back/stern stay.... I assume Mirage 26 will chime in with some input or at least results.

bffatcat · Jun 24, 2009

Check my post Ron I inquired about the condition of the standing rigging

Bffatcat

Mast pulled from deck

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no name

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