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WebSurfer3000 07-26-2010 04:02 PM

Hairline crack on mast
 
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Hi I have an old steel 43 ft boat with an aluminum mast of unknown name. The mast is a 43 ft (13 meters) in length. At the base of the mast there is a crack in star port and a larger one in port side of the mast. I could post pictures. Is there any way to fix the mast without spending more money than the boat is worth? I heard welding aluminum is out of the picture. And second does anyone know the factory for this mast? The boat is a 1978 - 13m Finot Reve Des Tropique (DREAM OF THE TROPICS)
Naval Architect: Jean-Marie Finot.
Thanks in advance.
George

tommays 07-26-2010 04:18 PM

It looks like corrosion built up between the mast and the piece inserted into the base that is part of the mast step


IF you can get the part out without destroying the mast :) you could clean it up and fill the parts with epoxy

I think a substantial wrap of fiberglass/epoxy on the outside the cracked area would be a fairly painless way to beef up the mast

CaptainForce 07-26-2010 05:31 PM

I think the safest and most conservative fix would be to cut off the bottom 10cm off the mast; remove clean and refit the insert for the mast step; and refurbish the step. It appears that the expansion from oxides developed with corrosion has split the mast. Of course, my suggested fix requires cutting down the shrouds and possibly a required move of the gooseneck or a bimini top adjustment. It's doubtful that this 10cm removal will result in an apparant change in performance, but a much improved security of the rig. Take care and joy, Aythya crew

cormeum 07-26-2010 05:32 PM

looks like someone tried drilling the mast to arrest the cracking already. you need to pull the insert whcih is probably where your problems lie. when that's addressed, welding a band on the base probably would only cost a couple of hundred- if the crack progresses the price to fix it mounts.
Capt. Force's solution is a good one too (if there isnt too much taper to refit the step)

mitiempo 07-26-2010 11:31 PM

I wouldn't think there is much taper at the heel of the mast.
What about doing what CaptainForce suggested but instead of shortening the rigging raise the step on the deck by the amount you cut off the mast.

WebSurfer3000 07-27-2010 01:59 AM

Thank you all for all the good ideas.
Does anyone know where I could order a raised step as suggested that I could rivet the mast on plus a collar for extra safety? (The piece must be able to be shipped to Cyprus in the med where the boat is on dry dock!)

mitiempo 07-27-2010 10:15 AM

It would probably have to be fabricated out of aluminum or stainless. Best to get it done locally I think.

scraph 07-27-2010 10:50 AM

I agree that cutting the affected portion of the mast, reinstalling the mast step insert and having a riser for the mast step fabricated and installed would be a good solution.

You might also want to attempt to determine the cause of this destructive corrosion and solve it before it happens later on down the road. Maybe you could do a hard powder coat to the insert and step to insulate them. Maybe also drill small drain holes at the base of the mast (I imagine water has pooled up on top of the step insert to accelerate this corrosion). If the component that is corroding is the step insert (instead of the mast itself) you could have a new one fabricated of a superior material.

I agree with all that the mast should be cut short and saved. The mast step and all involved components appear to be of dissimilar metals and also not very corrosion resistant. You might seek the advice of a local engineer or machinist on a better solution to the materials.

TQA 07-27-2010 11:57 AM

Hey guys it is at the base of the mast. Masts don't break there. I absolutely agree that it is corrosion related damage where the expansion has caused the "weld lines" produced during the posrthole extrusion process to crack.

But I do not see the need to shorten the mast. Get the base out clean it up get a GOOD ali tig welder to weld the cracks and then refit the base. Winding some carbon fibre / kevlar string and epoxy coating the base can not hurt from a strength point of view providing the top is water tight. But I think I would not bother preferring to leave it so that I could make a regular visual check on the welds.

A raised mast step would work too but I suspect the cost would be higher. Mind you it is a steel boat so a raised step would be easy to do. ?

scraph 07-27-2010 01:22 PM

Providing the mast is water tight? Or the reinforcement "jacket"?

I have no personal experience welding aluminum ... if those cracks can be cleaned and filled with weldment, absolutely. I imagine then it would make sense to really clean up those cracks. Grind a nice, clean channel in their place with a smooth radius at the termination.

It sure looks like that step insert though is a cast piece of carbon steel. That bothers me. I'd much prefer a billet of stainless milled to shape.


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