Cracked Mast at Spreader
 

I have a Isomat NG105 mast which is 61' long with a 7x11 cross section. There is a crack at the starboard aft end of the spreader base along where it was welded. I was planning to sleeve it with another section of an NG 105.
Today I was told I should grind off the old bases, put "Doubler Plates" about 6' long on the exterior, using a taper, fasteners and adhesive. Then replacing the bases and spreaders. This mast is one continuous extrusion and I hate to cut it if it can be avoided. Will this work? I will be sailing from Hawaii to San Francisco this summer. Does anyone have any ideas or recommendations?

Options
 

Hello,
First, the mast is already compromised by that crack, so is no longer exactly a continuous extrusion. The question is, how can you restore it?
If I am thinking of the same mast, the spreader bases are not flush with the mast, and they also take shroud loads, with stemball sockets built into the casting; not clear on how you could hope to double this one, except internally, and that would be a neat trick, but would provide strength too far away from that failing metal adjacent to the weld. So I like the grind-it-flush-and-start-over option. Lots of overlap, no stress risers, fasteners as well as adhesive -- it'll be stronger than new. Wouldn't hurt to drill-stop that crack first. And maybe six feet is more than you need.
Once the doublers are on, consider going with a saner configuration, with spreader brackets or through-mast spreader tenon, independent of conventional external tangs. The original configuration was a mass-production convenience, not the best way to do the two jobs. There's a reason they don't make them that way any more...
Fair leads,
Brion Toss

Omega 30
 

Hi, I have an Isomat NG-31 Mast with the welded on spreader roots with stemball and no through bolt also. The crack is small and i wish to fix it before it deforms. There are parts from Rig-Rite with aluminium doubler plates that fit a "through-mast spreader tenon" with stemball.

Doubler Plate for BF-3 SS Spreader Bar:

SS Spreader Bar for BF-3 Spreader:

Would this work?


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