Mast repair options

[Elie]

There is no need to answer all the insurances and marina responsability. This is notr part of the problem for witch I solicited knowledge on this forum. It seems that many opinions and comments do not take into account the simple fact that the breakage is roughly 5 inches on the side that is in fact 12 inches wide!.
However, I was able to contact an aircraft ingeneer, professor in aircraft structures. His speciality is calculations of wing structures. To him, it is an easy problem to solve: A patch well attached by rivets on each side of the mast will do the job and more. That is what is done as I understrand on main spars of the wing structure when is it affected by accident or corrosion. He will provide me will all the plans of part, and I will have then fabricated by a local shop that do work for aviation industry.

[jimbunyard]

Originally Posted by valhalla360

Please let us know where you do your design work so we can avoid those unsafe areas.

If you don't understand how taking out the entire side drastically reduces strength, anything you design is suspect.

Please, demonstrate where the 'entire side' has been "taken out'. Or are you unable to view, interpret and/or understand the illustration provided by the OP?

Conversely, since you profess to be able to calculate the loss of 'strength' associated with said 'massive damage', please give a reasonable value of both the amount and a definition of the 'strength' that is lost. It might also be interesting to see the calculations used, but I fear they may not make much sense to me...and likely anyone else...

I'd certainly appreciate you keeping yourself away from anything I've dealt with, for fairly obvious associative reasons...

[Elie]

Originally Posted by valhalla360 View Post
Please let us know where you do your design work so we can avoid those unsafe areas.

If you don't understand how taking out the entire side drastically reduces strength, anything you design is suspect.

Where did you get the idea that the entire side of the mast is taken out?...
The design work was done by a structural engineer at 'École Aerotechnique de St-Hubert, a highly regarded aircraft technical school in Montreal.

This forum is difficult to deal with at times, I suppose this has to do with the anonimity of the participants.
The breakage of the mast affects an area of less then 5x2 inches , on the side(no front or back affected) on a mast that is 12x5 inches of circonference, and partial interior doubling in the form of an inmast furler support. to restore any lost strength, the offered solution by aircraft structure specialist, is quite simple and it will in fact add a significant security factor.

[admiralslater]

Originally Posted by Elie

Remember, I'm a Canadian and we deal differently then some Americans with problem. But mostly, the real question I'm asking is technical opinion. For the legal/insurance problem its another subject.

I am Canadian as well, and I insure a boat in the Caribbean. I it was me I would call the insurance and at least find out what the situation is . If you have liability only that is a more complicated senario.
Boat insurance is not like car insurance , there generally aren’t rate hikes on individuals ( hurricanes may be different)

[chris95040]

Originally Posted by Elie

a mast that is 12x5 inches of circonference

Originally Posted by Elie

...aircraft ingeneer...

You should not be doing this repair yourself.

[pcmm]

If designed well, the patch could end up looking like its supposed to be there anyway!

[Elie]

Originally Posted by admiralslater

I am Canadian as well, and I insure a boat in the Caribbean. I it was me I would call the insurance and at least find out what the situation is . If you have liability only that is a more complicated senario.
Boat insurance is not like car insurance , there generally aren’t rate hikes on individuals ( hurricanes may be different)

I know, and I need not to say that my insurers are well aware of this accident, and I have a good understanding with them. But as often stated before, I'm posting a thread on this forum to try to get some technical information about mast repairs, and I'm not looking for anything else. I'm assured that this repair is doable, and much less of a trouble then replacing the whole extrusion. It is more efficient, faster, and I think more conform to our quest to be environmentally relevant. And I shall ladd that this idea is also a personnal challenge as well, and treat it like a project.

[Elie]

Originally Posted by chris95040

You should not be doing this repair yourself.

Why?. On what basis do you juge ?

[Cheechako]

Originally Posted by Elie

There is no need to answer all the insurances and marina responsability. This is notr part of the problem for witch I solicited knowledge on this forum. It seems that many opinions and comments do not take into account the simple fact that the breakage is roughly 5 inches on the side that is in fact 12 inches wide!.
However, I was able to contact an aircraft ingeneer, professor in aircraft structures. His speciality is calculations of wing structures. To him, it is an easy problem to solve: A patch well attached by rivets on each side of the mast will do the job and more. That is what is done as I understrand on main spars of the wing structure when is it affected by accident or corrosion. He will provide me will all the plans of part, and I will have then fabricated by a local shop that do work for aviation industry.

I think it was mentioned earlier, but Masts are built with doublers or sleeves etc all the time. Often the plate is secured on with various rivet devices and structural epoxy between the plate and the mast if it's external. Some racing designs with tiny mast sections beef up the trouble areas this way from the get go to save weight while remaining strong in the right places.
I had an in mast furling mast for a large boat rebuilt, and the spar company suggested we put large doublers around the mast opening for the reel/furling rope. They did it this way and showed me a racing spar they had there that typically had it for a class racing boat design. It came out very nice and super strong!