As part of spring prep for my 1985 Cat 30 recently purchased, I replaced the mast exit blocks for the internal halyards. When I removed the 6 screws it was apparent that the screw holes were badly corroded and when I replaced the exit box several screws turned freely becasue the internal threads were corroded away. I of course planned to go sailing later today but am now in maintenance mode. Short of replacing the mast, suggestions for how to repair this problem and make sure its safe for windy SF Bay use? Thanks in advance.
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OK, here come some suggestions.
I had a turning block on my Ericson shoot into orbit because I didn't through bolt it. I used the replacement block for a template and marked the other side of the mast and drilled away. The benefit was that I then had a mount on the other side for another block. This may or may not work for you but short of having your old holes welded shut and re-drilling, or drilling out the corrosion until you have a really big hole, thats about all you can do.
I had a turning block on my Ericson shoot into orbit because I didn't through bolt it. I used the replacement block for a template and marked the other side of the mast and drilled away. The benefit was that I then had a mount on the other side for another block. This may or may not work for you but short of having your old holes welded shut and re-drilling, or drilling out the corrosion until you have a really big hole, thats about all you can do.
How about Marine-Tex
Thanks for the suggestions. How about cleaning the holes out with a wire brush and then filling from both sides with Marine-Tex epoxy, which West Marine claims bonds like steel to aluminum and can be drilled and tapped?
Thanks for the suggestions. How about cleaning the holes out with a wire brush and then filling from both sides with Marine-Tex epoxy, which West Marine claims bonds like steel to aluminum and can be drilled and tapped?
Dave, you're asking two questions...
The first is how to repair the exit box. It isn't the screws' threads that are failing, the issue is that your aluminum mast became an anode and dissolved over time in the presence of salt water while the more noble stainless fasteners remained unaffected. This is such a common, almost always inevitable problem that I wonder why the thousands of customers who buy the mass produced boats each year don't arise in unison and make a huge stink about something as simple as installing mast hardware with a proper bedding compound. (Or maybe manufacturers do now...anyone know?) You will probably be fine if you just drill out the stainless hardware, and move up a size or two in fastener dimension sufficient for the remaining aluminum to give a purchase. Each new screw gets a slight but thorough application of Tef-Gel (visit www.briontoss.com if you don't know where to get this; this is NOT the rip-off product now sold by WM - Tek-Gel). There are many things that can be used to insulate (in a pinch, use silicone sealant or a bedding compound) but Tef-Gel's the best and a small tube lasts a long, long time. The second question is 'What is this a symptom of...?' and the answer is anything else on the boat where dissimilar metals see splashing spray or anything more solid. Think about removing - with patience - all of your other mast and boom hardware over time to check for other nasty surprises (after all, you do point out how windy it is out there) and rebed as above. It's a great time to think about things like the electrical connections on the nav lights (copper, brass, stainless), how well sealed the VHF antenna connection is at the masthead, and so forth. Chip away (sorry for the pun...) at the obvious list and you'll not only find problems if they exist but prevent further damage which, inevitably, will make itself know at the wrong time. Hang in there; you are a member of a large club!<g> Jack
The first is how to repair the exit box. It isn't the screws' threads that are failing, the issue is that your aluminum mast became an anode and dissolved over time in the presence of salt water while the more noble stainless fasteners remained unaffected. This is such a common, almost always inevitable problem that I wonder why the thousands of customers who buy the mass produced boats each year don't arise in unison and make a huge stink about something as simple as installing mast hardware with a proper bedding compound. (Or maybe manufacturers do now...anyone know?) You will probably be fine if you just drill out the stainless hardware, and move up a size or two in fastener dimension sufficient for the remaining aluminum to give a purchase. Each new screw gets a slight but thorough application of Tef-Gel (visit www.briontoss.com if you don't know where to get this; this is NOT the rip-off product now sold by WM - Tek-Gel). There are many things that can be used to insulate (in a pinch, use silicone sealant or a bedding compound) but Tef-Gel's the best and a small tube lasts a long, long time. The second question is 'What is this a symptom of...?' and the answer is anything else on the boat where dissimilar metals see splashing spray or anything more solid. Think about removing - with patience - all of your other mast and boom hardware over time to check for other nasty surprises (after all, you do point out how windy it is out there) and rebed as above. It's a great time to think about things like the electrical connections on the nav lights (copper, brass, stainless), how well sealed the VHF antenna connection is at the masthead, and so forth. Chip away (sorry for the pun...) at the obvious list and you'll not only find problems if they exist but prevent further damage which, inevitably, will make itself know at the wrong time. Hang in there; you are a member of a large club!<g> Jack
Jack, I bought Tuf Gel at West Marine and
rebuilt my mast. But I ran out of it and went back to the store. GONE! Figures. They had some other stuff designed to maximize profits. WM is a publicly traded company now and hasn't been the same since. I called Tuff Gel direct and they saved the day. Don't ask me for the number, I have to look it up.
rebuilt my mast. But I ran out of it and went back to the store. GONE! Figures. They had some other stuff designed to maximize profits. WM is a publicly traded company now and hasn't been the same since. I called Tuff Gel direct and they saved the day. Don't ask me for the number, I have to look it up.
I don't know about Tuf(f) Gel but here's the link
This is the real deal...and maybe longest URL every used.<g> Jack
This is the real deal...and maybe longest URL every used.<g> Jack
rivets?
a lot of mast hardware on my c380 is done with rivets. the gooseneck is very heavily loaded and it is attached with rivets. the rule of thumb is to use aluminum rivets if the fitting is loaded in shear, and stainless rivets if it is loaded with a direct in line pull. i use a product i got from hall spars called durolac. it is especially made for the purpose of separating dissimilar metals.
a lot of mast hardware on my c380 is done with rivets. the gooseneck is very heavily loaded and it is attached with rivets. the rule of thumb is to use aluminum rivets if the fitting is loaded in shear, and stainless rivets if it is loaded with a direct in line pull. i use a product i got from hall spars called durolac. it is especially made for the purpose of separating dissimilar metals.
long link address
for those long links try tinyURL.com does just what is says makes those long links tiny
for those long links try tinyURL.com does just what is says makes those long links tiny
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