wharfrat
06-28-2002, 03:21 PM
My 22 foot sailboat has an aluminium mast with single shrouds. The lower set fit into the tang, which also incorporates a socket for the aluminium spreader. The name of this part eludes me; I’ll refer to it as a tang/spreader plate. It is stainless steel and is riveted to the flat sided oval mast. The port side spreader has been knocked backwards by something unforgiving and is about on a 10 degrees further aft angle than the STB spreader.
The damage is a twisted tang/spreader plate, which has popped one of the forward rivets and dinted in the mast. I would say the dint is about 3 inches long and about 3/8 inch in depth at it's deepest point (created by the edge of the tang/spreader plate). The dint is at the aft edge of the tang/spreader plate right underneath it, still on the flat side of the mast just as it starts to round off. I got the tang/spreader plate off and two of the 1/4 inch holes that the rivots went through have significent cracks around them.
My last option is to cut the mast at the dint which is have way up the 27 foot mast (3"X6") and insert a sleeve after getting the dint out and machine screwing it all back together. However first I would like to get the dint out with out cutting the mast in half. Perhaps by tapping it out with a long drift from the holes on the other side where the other tang/spreader bracket is rivoted on. This will have to come off anyway if I cut the mast in half. Then I would like to shape a piece of aluminium to the contour of the inside of the mast and aluminium weld studs to it in the same position as the existing holes for the tang/spreader plate. Then I intend to slide the reinforcing shaped plate down the mast with a long stick with a clamp devise on the end. with the mast lying with the damaged side down hopefully the studs will position themselves in the holes of the mast and I will be able to get nuts on them and then put on the tang/spreader plate and tighten them up using anti seize. The problem I see is the lack of strength of the aluminium studs which will be threaded. Stainless Steel would be better but then how would I fasten them to the aluminium reinforcing plate. (plate must be tight to the inside of the mast) The plate could be SS but then it would be difficult to shape it to contour of the inside of the oval mast.
I could go with a solid piece of aluminium for the inside reinforcement (say 3" thick and shape it and then tap holes in the appropriate places in line with the tang/spreader holes and then use Stainless Steel 1/4" bolts with Anti seize. If I make it about 16" or 2 feet in length I would then drill many holes in say four rows and machine screw through the mast into the solid piece above and below the splice
If anyone has any other suggestions or thoughts on the subject it would be greatly appreciated. Thank you to any and all that reply
The damage is a twisted tang/spreader plate, which has popped one of the forward rivets and dinted in the mast. I would say the dint is about 3 inches long and about 3/8 inch in depth at it's deepest point (created by the edge of the tang/spreader plate). The dint is at the aft edge of the tang/spreader plate right underneath it, still on the flat side of the mast just as it starts to round off. I got the tang/spreader plate off and two of the 1/4 inch holes that the rivots went through have significent cracks around them.
My last option is to cut the mast at the dint which is have way up the 27 foot mast (3"X6") and insert a sleeve after getting the dint out and machine screwing it all back together. However first I would like to get the dint out with out cutting the mast in half. Perhaps by tapping it out with a long drift from the holes on the other side where the other tang/spreader bracket is rivoted on. This will have to come off anyway if I cut the mast in half. Then I would like to shape a piece of aluminium to the contour of the inside of the mast and aluminium weld studs to it in the same position as the existing holes for the tang/spreader plate. Then I intend to slide the reinforcing shaped plate down the mast with a long stick with a clamp devise on the end. with the mast lying with the damaged side down hopefully the studs will position themselves in the holes of the mast and I will be able to get nuts on them and then put on the tang/spreader plate and tighten them up using anti seize. The problem I see is the lack of strength of the aluminium studs which will be threaded. Stainless Steel would be better but then how would I fasten them to the aluminium reinforcing plate. (plate must be tight to the inside of the mast) The plate could be SS but then it would be difficult to shape it to contour of the inside of the oval mast.
I could go with a solid piece of aluminium for the inside reinforcement (say 3" thick and shape it and then tap holes in the appropriate places in line with the tang/spreader holes and then use Stainless Steel 1/4" bolts with Anti seize. If I make it about 16" or 2 feet in length I would then drill many holes in say four rows and machine screw through the mast into the solid piece above and below the splice
If anyone has any other suggestions or thoughts on the subject it would be greatly appreciated. Thank you to any and all that reply