Boat Info: 1970 Islander 37 M S
I've searched for information but did not find a lot about the method used to evaluate a mast and when to replace it.
My mast has some (2 inches) corrosion at the base but nothing visible up the tube.
I read where racing boats have their mast's replaced due to.... cumulative stress loading. I'm a airplane mechanic and understand why a alum. mast is stain hardened and becomes brittle & fails under heavy load... specifically in a raced boat.
My question is geared against a non raced boat but 43 years old. Logic may dictate.. it may/ should be at the end of it's service life. If I was inspecting it in the airplane world... I'd strip the paint and inspect it for cracks and return it to service if found A Ok. I have the mast off the I-37 and did not see a bending set in the mast.
My reason for asking this question is receive advice, & what others have learned over the years. I understand the saying... if it ain't broke, don't fix it. I'm concerned about sailing in higher wind conditions and my mast fails. I could address the 42 year old mast now and save a much higher $$ expense, should it fail at sea. I was pricing new masts, they run about $ 4 K.
Note, the hull is in good shape, blister/ defect free. A lot of money has been spent on this boat. If I bought a new mast... it would not be throwing money away against a boat that need's everything else to be seaworthy.
I see you are an air plane mechanic. Have a question for you. Can air frames last "forever" if they are inspected regularly (and cracks and defects repaired). I know fatigue in a salt envivronment can be devastating on aluminum:
From above link:
"Investigation by the United States National Transportation Safety Board (NTSB) concluded that the accident was caused by metal fatigue exacerbated by crevice corrosion. The plane was 19 years old and operated in a coastal environment, with exposure to salt and humidity.
According to the official NTSB report of the investigation, Gayle Yamamoto, a passenger, noticed a crack in the fuselage upon boarding the aircraft prior to the ill-fated flight but did not notify anyone."
Also, I understand some planes use wire to move control surfaces. Is this wire and the fittings stainless steel? If so, would you know the type (316 or 303). How does an airplane mechanic inspect the aircraft cable and fittings? Do you pass the cable as good on a visual inspection, or does it need to be replaced based on age?
Seems planes and sail boats have a lot in common.
When I had my boat surveyed, I asked him how long the mast should last. His answer was forever, as long as I don't bend it.