I Recently bought a Catalina 27. One problem is the bottom of the mast shows a split about a 1/2 inch up from the deck. The prior owner drilled a small hole at the upper end of the split to stop it from running. How concerned should I be reqarding sailing under this condition. One person told me I need to pull the mast and have it welded.
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LaDonna Bubak - Catalina Owners
Yikes!
I would be very concerned about that! I'm sure that welding it would probably work just fine but I don't know if I personally would be comfortable with even that, considering the potential for disaster if it failed. I hate to say this but I hope you got a screaming deal on that boat. Good luck! LaDonna
I would be very concerned about that! I'm sure that welding it would probably work just fine but I don't know if I personally would be comfortable with even that, considering the potential for disaster if it failed. I hate to say this but I hope you got a screaming deal on that boat. Good luck! LaDonna
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Gene
Split
The problem with any response relating to a safety issue is it is hard to get an honest answer. Everyone is more concerned with covering their butt, especially if they are connected to an organization which could be sued! The first problem is you called the problem a "split mast," boy that sounds dangerous!!! But in you description it sounds like you are describing a 1/2" "crack" which has been controlled by drilling a hole at the end to stop it from spreading. The base of the mast is under compression hence there is no side loads or stress. Big question is what caused the crack, did the previous owner try to step his own mast. Would really quiz the previous owner to establish a cause. Worst case, what is going to happen, Is the mast going to break in two? Don't think so. If it was my boat I would just keep it under observation and not even weld it. Welding has the potential to cause even more problems.
The problem with any response relating to a safety issue is it is hard to get an honest answer. Everyone is more concerned with covering their butt, especially if they are connected to an organization which could be sued! The first problem is you called the problem a "split mast," boy that sounds dangerous!!! But in you description it sounds like you are describing a 1/2" "crack" which has been controlled by drilling a hole at the end to stop it from spreading. The base of the mast is under compression hence there is no side loads or stress. Big question is what caused the crack, did the previous owner try to step his own mast. Would really quiz the previous owner to establish a cause. Worst case, what is going to happen, Is the mast going to break in two? Don't think so. If it was my boat I would just keep it under observation and not even weld it. Welding has the potential to cause even more problems.
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John Visser
Don't worry about it
I agree with Gene, disagree with LaDonna. My recommendation: 1. ask previous owner about it, including how log it has been stable. 2. Check it occasionally. The chances of the rig coming down because of this are zero. If it becomes unstable, meaning it begins to grow or change, it can be welded fairly cheaply. Loss of hardness locally due to welding in this area is not an issue.
I agree with Gene, disagree with LaDonna. My recommendation: 1. ask previous owner about it, including how log it has been stable. 2. Check it occasionally. The chances of the rig coming down because of this are zero. If it becomes unstable, meaning it begins to grow or change, it can be welded fairly cheaply. Loss of hardness locally due to welding in this area is not an issue.
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Echo Gulf
No Problem
I agree with John and Gene, it sounds like the crack (not split) has been stopped. This method of stopping cracks from spreading is routinely used on commercial and military aircraft. If it continues to cause you concern, consider having the mast shortened by 1/2 inch (preferably by a machinist or similar qualified technician). The rigging should have enough adjustment in it to compensate.
I agree with John and Gene, it sounds like the crack (not split) has been stopped. This method of stopping cracks from spreading is routinely used on commercial and military aircraft. If it continues to cause you concern, consider having the mast shortened by 1/2 inch (preferably by a machinist or similar qualified technician). The rigging should have enough adjustment in it to compensate.
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Dave Bousquet
How does welding weaken the mast?
I have a groove that has worn on my mast, starboard side below the spreaders. It was caused by the topping lift. It was tied against the mast by the yard over the winter (2 years ago). The pad-eye rubbed against the mast and left a groove. I called catalina about it and they said its size and location on the mast were not an issue and that it could be left alone. I've sailed two seasons in some rough conditions with no problems. I was considering having the yard weld a bead of aluminum in the groove, but I was unaware that it would actually weaken the mast more. How is this so?
I have a groove that has worn on my mast, starboard side below the spreaders. It was caused by the topping lift. It was tied against the mast by the yard over the winter (2 years ago). The pad-eye rubbed against the mast and left a groove. I called catalina about it and they said its size and location on the mast were not an issue and that it could be left alone. I've sailed two seasons in some rough conditions with no problems. I was considering having the yard weld a bead of aluminum in the groove, but I was unaware that it would actually weaken the mast more. How is this so?
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Pete
Here's my $.02
Calling upon my metallurgy and engineering experience from years ago, here's my go at your problem. While you decide whether to remove the mast, I would place some type of band around the base as insurance against a sudden and catastrophic reopening of the split. Be careful of using dissimilar metals as this could cause corrosion problems - heavy duty plastic strapping may be good. Even with plastic, you should routinely rinse out any residual salt in any gap since the salt will tend to concentrate and cause the aluminum to corrode faster. Welding of any metal can be a problem for several reasons, depending on the particular composition and any heat treatment it has undergone. Because welding involvesapplying intense heat to a specific area, there will be a large temperature gradient around the area, with different areas seeing different temperatures and cooling rates. This results in small areas in which the heat treating is different from the rest of the structure. Welding also involves melting and re-solidifying portions of the structure. In doing so the composition can change over small areas. These areas can be more or less brittle, or more or less corrosion resistant, than surrounding areas. With all that said (and you're sorry you asked!), the aluminum may be of a composition that is readily welded without risk. You will just have to seek out someone with experience doing it. Good luck.
Calling upon my metallurgy and engineering experience from years ago, here's my go at your problem. While you decide whether to remove the mast, I would place some type of band around the base as insurance against a sudden and catastrophic reopening of the split. Be careful of using dissimilar metals as this could cause corrosion problems - heavy duty plastic strapping may be good. Even with plastic, you should routinely rinse out any residual salt in any gap since the salt will tend to concentrate and cause the aluminum to corrode faster. Welding of any metal can be a problem for several reasons, depending on the particular composition and any heat treatment it has undergone. Because welding involvesapplying intense heat to a specific area, there will be a large temperature gradient around the area, with different areas seeing different temperatures and cooling rates. This results in small areas in which the heat treating is different from the rest of the structure. Welding also involves melting and re-solidifying portions of the structure. In doing so the composition can change over small areas. These areas can be more or less brittle, or more or less corrosion resistant, than surrounding areas. With all that said (and you're sorry you asked!), the aluminum may be of a composition that is readily welded without risk. You will just have to seek out someone with experience doing it. Good luck.
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John Visser
Welding weakness
The only weakness issue with welding is that any heat treatment of the mast will be ruined in the area of the weld. Honestly, if this crack has been stopped by drilling, meaning it is stable for some time, don't even worry about it. jv
The only weakness issue with welding is that any heat treatment of the mast will be ruined in the area of the weld. Honestly, if this crack has been stopped by drilling, meaning it is stable for some time, don't even worry about it. jv
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Garry @ S/V TASHTEGO
Welding
Your mast is almost certainly aluminum alloy 6061 T6. The T stands for temperature hardened and 6 is the highest level of hardening. 6061 T6 has a tensile strength of about 40,000 psi. Welding anneals the area around the weld. Annealed 6061 has a tensile strength of only around 3,000 psi. Welded 6061 extrusions (like your mast) are prohibited on Navy vessels because welding seriously weakens the metal. The band around your mast is a much better idea. I'd wrap the mast with a plastic insulator of some kind and a couple of large stainless steel hose clamps. Keep them as clean as you can and don't let the stainless steel rest directly on the aluminum.
Your mast is almost certainly aluminum alloy 6061 T6. The T stands for temperature hardened and 6 is the highest level of hardening. 6061 T6 has a tensile strength of about 40,000 psi. Welding anneals the area around the weld. Annealed 6061 has a tensile strength of only around 3,000 psi. Welded 6061 extrusions (like your mast) are prohibited on Navy vessels because welding seriously weakens the metal. The band around your mast is a much better idea. I'd wrap the mast with a plastic insulator of some kind and a couple of large stainless steel hose clamps. Keep them as clean as you can and don't let the stainless steel rest directly on the aluminum.
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