Rotating mast step catamaran

[snowcat 0]

I have a rotating wing mast on my 12m catamaran. I recently took the mast down for the first time and discovered that it is pivoting on a long pin, which slides into a sleeve in the mast. (See photos) This now explains why the mast base keeps coming loose and the mast binding up because as the rig leans the pin jams. I am looking for feedback on a new mast base design. I am considering welding a 3.5 tonne tow ball onto a steel plate and creating a cup in the bottom of the mast.

Will this work? Or is there a better solution.

Thanks

[Frank 192]

A tow ball will concentrate the loads over a much reduced surface area, given the consequences of failure I would consult the original designer or another who has designed performance multihulls Roger Hill @Roger Hill Yacht Design could likely give you some good contacts. 

[TimB 7]

Balls have been used often, sometimes stainless steel, sometimes even a hard wood. The mast has to be able to wobble a wee bit, as the shrouds are usually a little bit loose to allow for the rotation.

The cup and curved surface should work. Need to make sure the mast can't jump off and the tube would do that but it needs clearance.

 

Cheers