here it is!
stephen
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Small world eh??
I have trouble with the joiners in my "converted" one piece masts bending (They have a lot stress 1/2 way up the mast)
The joiner is 4.8mm aluminium machined to the correct taper, which usually ends up about a 3mm wall thickness at the top of the base section joiner.
These were bending, so I fitted a hard wood insert, I turned up on the lathe and glued into the full 400mm (200mm in/out as the joiner) and this has still bent on a 5350mm IMCS 29 mast.
The proper carbon joiners must be VERY solid.
The stress on the bottom of the mast will be even greater, so I would be hesitant to extend it here.
I like the vacuum cleaner solution much more.
I have machined up timber extensions for the tip, if they are sticking out less than 200mm and the mast tip is still greater than 35mm, otherwise a tube extension is needed, as the mast stands a chance of splitting from the localised internal pressure combined with a reduced diameter of the mast tip. Particularly in the event of an upset.
The feather banners you see for advertising have a 6 piece telescopic carbon mast inside them, with a "smorgas board" of sizes, just for this job.
I found 3 broken ones thrown out behind our local art centre, while waiting for my wife.
Don't forget the 25mm x 3mm Flat bar, mast strap, as there are some huge stresses applied to the mast step. don't weld it all the way round though.
This is "Landyachts" solution and has worked to date. This is a pic of my yacht #1, "Code Red"
