Standing Rigging Question

[ack]

I have a 45' Bruce Roberts (fiberglass), sloop rig, with internal chain plates and I'm in the planning stage to switch to external chain plates. The rigging on this boat is somewhat atypical in that the lower shrouds are not symetrically spaced from the main upper. The aft lower measures, from the main, 31 inches or 84.4 degrees. The forward lower measures, from the main, 80 inches or 75.87 degrees. The mast spreader has zero aft sweep and I can only assume the original rigger configured the lowers this way to prevent mast pumping? I've had this boat about ten years and the unusually forward lowers have not been much of a problem as yet, but the boat doesn't get sailed all that much either. I hope to cruise full time within five years and want external chainplates for ease of inspection and access. My questions are:

1) Does this lower shroud configuration serve any real purpose?

2) If I change to external chainplates and the answer to #1 is no, how should I configure the chainplates?

[Brion Toss]

Hello,
First, it is extremely rare to have lower shrouds at the same angles, laterally or fore-and-aft. Most often, the aft lower has more "sweep" in both planes, which makes for difficulties in tuning; if the same tension is on both wires, the mast will move aft at the attachment point, which is the opposite of what we want. Also, the further the aft lower is swept aft, the sooner the boom hits it when you are off the wind. So I like it when the forward lower has a bit more sweep. But 80 inches? Really? If I understand you correctly, this is really silly. It serves no purpose, and will limit spinnaker pole travel.
As for the external chainplate idea, don't do it. Inboard chainplates, properly installed, can be just as accessible and inspectable as outboard ones.And they can be less vulnerable to corrosion. Plus they will allow for appropriate sheeting angles, and usually make for better deck traffic ergonomics. Oh, and moving the chainplates outboard often makes for problems with compression on the bulwark.
Fair leads,
Brion Toss