Typically yes. Although there was another thread in the FCT forum of a rotating mast ball failing, perhaps a manufacturing defect?solid metal, right? Non-compressible for all intents and purposes.
That or shear loads failure. Lotsa shear load when raising the mast. Depending on the geometry, could get shear loads while sailing if rig is canting (or just loose).
Old thread but I'm finally trying to get my boat launched within a year. Amgpuma: where did you source your ball? I'm looking for a stainless trailer ball hitch in the 1-7/8" size.. I'm thinking of using Kurt Hughes's design, which is water-catcher mode.. maybe not the best but he likes it so since I have no experience will do as my designer says. Similar to this (second image is different boat than first image, but same idea):My tow ball SS is 750 grames while Ti is over a pound (475 grames) Thas not even the weight of a can o beer. Bending stiffness pre and post fatigue with such weight is also pointless for pourposses.
It's fine. I'm sure it is 304. The boat is dry-sailed and washed off after every sail, and the ball is ridiculously over-spec for the application, corrosion on a 304 part is the least of my worries to be honest. The ball and cup with cutout has worked flawlessly in raising and lowering the mast with no extra hardware needed at the mast base, so that's a nice clutter reduction.Thanks KONeill, I had seen those and figured they were 304 stainless rather than 316L since they don't say the grade. How is it holding up for you?
How hard can it be? You got a drawing?Can Colligo CNC mill the F-39 ball? Is the ball for the F-39 the same as the 44 cat that Farrier designed? Anyone have a source for a cnc or lathe guy who understands what is needed for a rotating mast ball and socket? I can not find a 3" off the shelf road trailer ball in 316 to save my life. 70,000 lbs mast compression on a 50' day charter 49 passenger CG inspected cat.
You could just call up Aquarius Sails and get a Supercat 20 mast base.....Hi Groucho,
I am looking for a solution similar to what you suggest.
I got a mast from the SuperCat 20 for my Sardine 23 trimaran project and need to build a mast step that will fit. The trailer hitch solution seems a little overengineered and heavy.
Can you show your fiberglass mast step, that seems like a good approach.
How did you achieve a halfway smooth ball shape? what female mold did you use?
Greetings from California
Thank Groucho for the comments on making the ball joint.Difficult to see but you can get the idea. I roughly shape a wooden base then sand to make a semi-circular shape for the male bearing, then glass coat. The female bearing takes a bit longer because you're having to cut and grind to make a hollow cup. Glass that too. You can then mate the two with sandpaper between the two to get a smooth surface. And then a thin layer of lubricant. On the male bearing you cut away some of the lower area of the base - so that when lifting mast the female cup can sit on the male bearing edge. Once the liting compression loads go up it will slot into position.
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