Any one happen to know their spreader lengths?

[Mike]

Hi, what began as a bit of routine maintenance is fast turning into a slightly more involved overhaul.

Next on my list is getting new spreaders as the old ones have heavily corroded ends.

This should be simple, the mast is already on trestles, but I've found ways to complicate it

I'd noticed other single spreader rig boats seemed to have wider spreaders proportional to their size, and when I thought about it, the rig tension had seemed quite tight on my boat compared to others.

My suspicions were confirmed in Brian Toss's fantastic book, The Rigging Handbook- well worth a read, and Brian's flair for narrative make it great fun as well as informative.

Apparently wonderful things happen on the compression vs lateral resistance curve at around 12 degrees of angle, so spreaders should be set at a length to provide that 12 degrees between upper and mast. Mine was more like 9.5 degrees, which introduces a considerable amount more rig tension and compression to the mast if the shrouds are tensioned to stop the mast bending overly on a heavy beat.

This might explain why my shrouds have worn a groove at the bottom of the slot where they emerge from the mast- not enough angle! It all started to make sense.

Seems like a great opportunity to amend this, and there is a bit more room between the genoa and spreader tip when sheeted in, around 15cm from memory, which would get me a good deal closer to the magic 12 degrees.

However, before I get carried away fixing problems that might not actually be problems and meddling with forces I am only beginning to understand, thought I'd check and see if anyone else happened to have been up the mast with a tape measure, or even had a good direct angle photo of their Top Hat rig, or just knows about these kinds of geometric adventures?

After all, it is a heavy mast section, and all may be just as the designer intended?