mast hold down repair question

[Zippy]

Greetings - I have a 1989 E 32-200 and over the years the mast hold down has been slowly cracking the inner coming where the mast passes through, is this normal? I'm wondering if this is due to flexing of the cabin top or the yard guys cranking too hard on the turnbuckle where it attaches.

My repair plan was to mix up some West System epoxy with CSM and silica, trowel the mix into the void with the stainless hold down in place so it molds a nice groove for future placement. The final step is to drill a hole through the cured epoxy mix for the bolt that keeps it in place.

Has anyone else done this type of repair? You can see that someone before used Bondo but obviously that didn't work very well......

Thanks!

 

[Christian Williams]

I'm not familiar with that particular strap, but it's probably there to hold the mast collar down against the upward forces of the halyards on the turning blocks.

That's probably the sort of repair I'd do, just to assure that the strap has a firm surface and the surface is able to spread the load.

 

[Pete the Cat]

I have that same strap on my boat. As you say, this shows a boffo "repair" job of some vintage. I would do what Christian suggested: You are going to need to do a fair amount of grinding to get all that crud out of there. You will need to lay up several layers structural mat fiberglass cloth and bond it back from the rim of the mast hole (AKA "partners") several inches. there is generally not shock load at this point (unless the boat was hard grounded--which can create immense downward shock force on the mast and mast step--my slip neighbor just put his mast through the bottom of his brand new racing boat hitting something) so your idea that someone over tightened things too much makes sense. Hard to actually see in the picture, but it also appears there might have been a layup problem in the original glass that caused delamination and failure. Take your time. This is going to be a fussy but doable job. I would ask someone in the boatyard what they are using for heavy structural glass cloth these days. I would offer some types I have used, but I am out of date with the new products folks are using. Are you sure this boat does not have grounding damage elsewhere? if it is out of the water, look carefully at the trailing edge of the keel/hull joint. If you see a bunch of cracks, you might have more grinding to do. Seems like it would be a good idea to see if you can find evidence of what caused this as you fix it.

 

[bgary]

I'm wondering if this is due to flexing of the cabin top or the yard guys cranking too hard on the turnbuckle where it attaches.

Probably that second thing. It's a tie-rod, not a stay, but people often seem to want to tension it like crazy.

The right amount of tension is "firm" to the point where it doesn't rattle. The goal is to keep shroud tension from distorting the deck upward (not so much a problem on our Ericsons, where shroud tension goes through the deck to the grid)

Tighter than that and it may distort the deck (and/or cause the kind of damage you're seeing).

 

[Pete the Cat]

Probably that second thing. It's a tie-rod, not a stay, but people often seem to want to tension it like crazy.

The right amount of tension is "firm" to the point where it doesn't rattle. The goal is to keep shroud tension from distorting the deck upward (not so much a problem on our Ericsons, where shroud tension goes through the deck to the grid)

Tighter than that and it may distort the deck (and/or cause the kind of damage you're seeing).

FWIW, I think the purpose of this tie rod is also to off set the pumping of the halyards against their deck attachments and turning blocks. Folks often underestimate the shock loads a boat endures in those tacks and jibes. Short duration, high load. My neighbor's brand new Farr racer just shattered a carbon fiber compression post and drove it through the bottom of his new boat after just hitting a large wave. Viewing the destruction was frightening. I did not see a lot of poor workmanship in the actual layup. Probably some design issues, but sobering. Out boats and Ericsons, in particular, were grossly over built in general, but do not escape the laws of physics.

 

[Zippy]

I'm not familiar with that particular strap, but it's probably there to hold the mast collar down against the upward forces of the halyards on the turning blocks.

That's probably the sort of repair I'd do, just to assure that the strap has a firm surface and the surface is able to spread t

I have that same strap on my boat. As you say, this shows a boffo "repair" job of some vintage. I would do what Christian suggested: You are going to need to do a fair amount of grinding to get all that crud out of there. You will need to lay up several layers structural mat fiberglass cloth and bond it back from the rim of the mast hole (AKA "partners") several inches. there is generally not shock load at this point (unless the boat was hard grounded--which can create immense downward shock force on the mast and mast step--my slip neighbor just put his mast through the bottom of his brand new racing boat hitting something) so your idea that someone over tightened things too much makes sense. Hard to actually see in the picture, but it also appears there might have been a layup problem in the original glass that caused delamination and failure. Take your time. This is going to be a fussy but doable job. I would ask someone in the boatyard what they are using for heavy structural glass cloth these days. I would offer some types I have used, but I am out of date with the new products folks are using. Are you sure this boat does not have grounding damage elsewhere? if it is out of the water, look carefully at the trailing edge of the keel/hull joint. If you see a bunch of cracks, you might have more grinding to do. Seems like it would be a good idea to see if you can find evidence of what caused this as you fix it.

Thanks Pete and Christian for your input. I mixed up some epoxy resin and chopped strand with silica the other day and troweled it into the void with the tang in place so it would mold around it (on the back side of it only - so I can get it out if I want). I also layed up two layers of wetted out 1708 structural fiber glass, also imbedded into the epoxy mix. once it cures I'll grind it all fair and apply some gelcoat to pretty it up

 

[Pete the Cat]

Sounds perfect. I don't think you can see any of it after it is all covered, so the gelcoat seems unnecessary, but whatever you like. Good job.