Double Lower Shroud Tangs

[Brob76]

I am in the process of replacing the standing rigging on my Alberg 35 (new wire and Hayn turnbuckles/comp terminals). I've gotten everything sorted out except for the lower shroud tangs. The four lowers were originally 7/32 wire and I plan to replace with the same. The current setup consists of through-bolted (with compression tubes) stainless spreader roots with an intergral tang. Double delta plates (if that's the correct terminology) with 1/2" upper clevis holes and 3/8" lower clevis holes (for eye fittings) attach to the integral spreader root tang as shown below.


I would really like to make a stronger/simpler mast attachment for the lowers. The spreader fitting is 1/8" plate and the clevis hole has stretched and deformed a bit as shown below. This was obviously a retrofit as the original Pearson spreader roots were an aluminum casting. I'm not sure how the lowers attached originally. Seems like the 1/8" plate was a bit undersized.


I was wondering if it would be better to cut away the integral spreader fitting tang and fabricate tangs of ~3/16"x1" stainless flat bar and attach directly to lower spreader fitting bolt which is 1/2". I would then use the Hayn toggle forks rather than eyes. Seems like a simpler and stronger solution. I was thinking of doing something like pictured below (courtesy of www.bristol29.com) or possibly making a solid triangle plate from flat bar rather than the two separate straps.


Does this sound like a viable option or should I stick with the current config and fabricate heavier spreader fittings?

[Brion Toss]

Hi there,
Yeeks, someone got unengineeredly creative there. Cut off that tab, as you described. Ream the deformed hole to accept a shouldered stainless bushing, suitable for a 1/2" throughbolt. This will clean up the deformation in mast and tangs, plus provide a larger bearing surface. Hang a pair of double tangs on the throughbolt, the threads of which will have been cut so that they stop when they reach the bushing. That way you don't need a compression tube. I have the bushings if you can't find them locally.
If the old tangs are in good shape, and if they are properly bent to lead fair to the shroud and square to the pins, use those. Otherwise get new ones.
Fair leads,
Brion Toss

[Brob76]

Hi Brion,
Thanks much for the quick response. The deformed hole I was referring to is the one in the tab I plan to cut cut off. It is the hole the double triangle plate rode on. The hole I am planning to mount the tangs on is the lower hole of the spreader fitting in the picture (once the tab is removed). That hole and the corresponding hole in the mast wall are still in good shape..perfectly symmetrical. There are currently compression tubes for both lower and upper spreader fitting holes. Do you think it would still be prudent to over-drill the mast wall for 11/16x1/2 (or even 3/4x2) flange bushings to increase bearing surface shear strength? Something I'm not clear on is elimination the compression tubes. I understand the concept of eliminating the need for compression tubes if the threads stop short of the flange but being that these are spreader fittings, won't the compressive load on the spreaders tend to crush the mast without the tubes?

When you reference hanging double tangs on the through-bolt, are you referring to double strap style tangs like the ones shown in the last picture above? I was planning to fabricate similar tangs and use toggle forks. The old fittings are double triangle plates that hang off that tab I'm removing with eye fitting between. These fittings are not bent. The tab I am removing was the part that was bent out to provide the fair lead. The new tangs will be bent the same as the tab so the shrouds lead fair.

Thanks for your help,

Brian