Importance of cap shrouds being in column ?

[Jon Neely]

Hi guys, currently putting on new chainplates on my HC33. I talked to Brian at this years Strictly sail West bouncing the Idea of mounting external plates made of bronze due to the originals come out of the cap rail and are glassed into the hull. I feel I left with Brian giving me the nod of approval for the idea. Making my jigs out of aluminum plate so I can get all the bends (two of them) perfect on the 3/8'' aluminum bronze plate. While staring at the main cap shroud I noticed under the spreader it take a good turn aft. Now after listening to Brains seminar I am under the impression everything should be in column and this to me seems odd. Now I know our boat is a little different because It has a tabernacle mast which I think its the only one of its kind in the HC line up. So my question is while Im mounting the new plates should I relocate the cap shroud plates so they become in column with the top of the mast. Currently they are about 7'' too far back from having a direct run. I Am attaching some photos to try to show what I am seeing. Seems to me the current design must put a lot of stress on the spreaders.


Cheers,

Jon

[Brion Toss]

Hi again,
No good reason for that bend to be there; you are right, the wire will be constantly trying to tear the spreaders off, and one day they will succeed. Possibly the designer had raked spreaders in mind, possibly the mast was stepped further forward than designed, possibly the chainplates are too far aft.Rake wouldn't affect this. Hmm. No harm in raking those spreaders, I suppose, but no significant benefit either. If you are interested, just pull the forward pin on the current spreader roots, and watch as the spreaders magically line up, showing you a chainplate-compatible rake. Then you could get new spreaders made that conform to the angle. If you want sane athwartships spreaders, you'll need to move the chainplates.
Fair leads,
Brion Toss

[Jon Neely]

Thanks for the reply Brian! Pulling the stick tomorrow and will look for stress fractures on the spreaders. If you where having to decide wether to change the spreaders or move the plates what would you do personally? The only negative side I see with moving the chainplate is it would be potentially less strong because Im not tapping into the old root system of the old chainplates. From what I heard from the builder is that the original pates go strait to where I am drilling the new ones but from there they go to a "s" shape and continue down the curvature of the hull for a few more feet.

On another note, be sure to say hi when you come and visit Peter on Pegasus here in Berkeley. Hopefully we will be up and sailing by then.

[Jon Neely]

PT.2, Got the mast down today!!! quick question, lots of screw that haven't been moved in years and where not coated at all. After heating them I still am breaking off about 50% of them. Do you have a better method? For the screws that have broke do I leaved the stainless or do I attempt to drill them out?

Thanks!

Jon

[Brion Toss]

Hi again,
Ah, frozen fasteners. Heat, Kroil or P Blaster, and especially an electric impact driver are your friends here. Also cursing. Even if you get all the rest of the fasteners out intact (unlikely), you will still have at least a few stubs. If you try to remove them by drilling, you will almost certainly have the bit wander off-target and punch through the adjacent aluminum. But if you leave them there, you won't be able to put the fitting they were holding back in its original place. What then? If you move it a slight amount, you'll have holes that are too adjacent for comfort. But if you move it a lot, you could end up with fittings that are poorly placed.
So do your best to get the rest out -- for reasons we can go into if you like -- and hope that everything is already poorly placed, so you can drill fresh holes, far away, in the right place.
As for altering spreaders vs. chainplates, the continuous reinforcement of the original structure is a good thing, especially for the uppers, which take almost half the total transverse load on your boat. On the other hand, most boats don't have that setup, and do just fine, so long as the chainplates are mounted with sufficient distribution area.
Fair leads,
Brion Toss