mast sleeve

[jedkins]

Hi,

Can anyone help me with a design for a mast sleeve.? Specially, I need to sleeve a Hobie 16 mast about 1 foot above the gooseneck

Thanks

[frosh]

Hi, this is risky even with a really good sleeve as this location is the most highly loaded of all. In theory the sleeve should be of a similar material and exactly the same shape as the mast section, but smaller, so it fits precisely inside the original. If this is available it might be OK by gluing in with epoxy, but if the sections do not match really well it will probably break again.

[jedkins]

Thanks for input. The mast could be reversed by swopping mast head and foot. Sleeve would then be at the top, actually just 2 feet 6 inches from top.
Any idea of what the stress is like up there? I understand how a sleeve works
but dont know how to go abt building one , also unsure what material to use

[frosh]

Hi, the stresses about 2 and a half feet from the head are very much less.
I don't know whether a quality sleeve can be built at home. The Hobie mast is sort of an elliptical section I think in aluminium. I assume that you can't buy the same section a few mm. smaller as this would be perfect. Otherwise sometimes it is possible to take a piece of the identical mast section, cut out a longitudinal sliver, and compress slightly, so it fits inside snugly. Use about 1 foot and glue with best epoxy glue you can buy.
Note; that to glue to aluminium effectively it needs to be degreased, and sanded until shiny and slightly rough. Then apply glue to both surfaces without delay.

[alex fletcher]

Hi jed find yourself a good aluminium fabricator welder and get him to fabricate a
tube the exact shape to fit inside the mast it must be Double the wall thickness of the mast and be more the 200mm long the butt of the broken mast is weld prepared with a chamfer that forms a vee when assembled insert the sleeve half way in one half of the mast Pop rivet it securely in position
push the other half of the mast over the sleeve Ensure the mast is straight
then Pop rivet it securely in place
now weld around the mast in the little Vee formed by the weld prep.
Then drill out the rivets and weld the holes over welding both the mast and sleeve a Angle Grinder with a fine flap wheel will finish it beautifully