the mainsheet
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At the request of Kevin Pegler (W1071) of New Brunswick, I hereby plug a hole that was left in my rigging sheets: the mainsheet. Thanks for pointing this out to me, Kevin!

Aboard SHADES, we have used a number of different mainsheeting systems, and I must say that I think the current system that we've been using for the past three years (see photo below) seems to be pretty well flawless for our needs. 
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You may be able to see that we used to use a(n adjustable) bridle with 36' of 5-mil softbraid for a mainsheet. 

This "new" mainsheet was once part of a very old spi sheet that was pressed into service at this year's Nationals. When our 8-mil braided rope being just a bit too short finally annoyed me enough, I took it out of the swivel cleat for a run and then rushed to re-thread it for a rapidly approaching beat. It was a close race with only half a beat to the finish, and a bad time to discover that I had (inadvertently!) installed a new barber hauler for the starboard jib sheet!

Well, I was not going to repeat that manoeuvre! So - during our on-the-water lunch, I rummaged about in the aft tank (which still had not quite returned to normal after Mike Mac had totally emptied it just to sail one club race at TS&CC!) and found our old 58-foot continuous spi sheet from before the days of the "balls system". It was in there to comply with the 25' towing line requirement plus it could be pressed into service if our somewhat frayed spi sheets gave up the ghost. And now it developed a third function: it was threaded in as a new mainsheet, tested for length with the bridle pulled as flat as it goes and the vang off. Then I left an extra two feet of rope just in case I had overlooked some possibility - and ended up with a mainsheet that is 36 feet long.
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Using a sheet that is no more than 8 mil. in diameter (preferably less!) not only makes your sheet cheaper to buy, it also enables you to use Harken (082) bullet blocks instead of larger, heavier, more expensive boom and traveller blocks. We have the kind of boom that has slides with U-brackets on its underside which means we have to use twist shackles to attach the bullet blocks to the U-brackets so that the blocks will face fore-and-aft as opposed to sideways. The block in the middle doesn't really bear any load and we have replaced it with a tiny shackle which still keeps the mainsheet off my throat as we gybe!
Note: If you don't have a boom that can use the slides, you can use eye-straps (without shackles if you fasten the eye-straps with the Harken 082 already threaded in) but make sure you use strong (stainless steel or Monel) rivets or #8 half-inch self-tapping screws (with the points filed off to avoid snagging on any outhaul ropes that may run inside the boom) since these eye-straps will bear a fairly heavy load!
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With apologies for my atrocious art work, the diagram below shows our system:.....

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We used to use a block with a becket at the end of the boom - which required one less slide - but I find I prefer the system diagrammed above with the end system that I just finished laying onto my scanner with the result at left:

You can probably see how thin that sheet is - it doesn't bother my hands but then I

  • have fairly tough hands
  • cleat and uncleat the mainsheet hundreds of times per race
The carabiner (left) is fairly permanently attached to the aftermost U-bracket on the boom but in last year's drifters on the Sunday of the Midwinters, it was nice to be able to unsnap it from the boom. 

This takes one purchase and a lot of rope pulling out of the system for places such as the leeward mark! And a thin sheet runs much more freely through its blocks, which is faster and sometimes safer!!
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The Swivel Block & Cleat Assembly
As luck would have it, I inherited what I believe to be the perfect swivel block assembly (see photo below). Made by Barton Marine and given the number 42600, it has a short, low-rise plate that attaches the metal cam cleat to its base. Much as I love Harken stuff of almost every description, I have dumped at least twice when using a borrowed boat that had their standard high-rise swivel cleat. The problem was that, during a tack, the sheet cleated itself on the Harken swivel whereas my Barton swivel takes a conscious effort to cleat - i.e. I have to reach down, or push on the sheet with one foot, to make it cleat. I find this easier to do than to explain, and for me, it is certainly much safer (and drier!) To find it on line go to Barton Marine > Products > Dinghy & dayboat fittings.
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I believe the glass boats tend to come with a spot provided for the swivel mount at the aft end of the centreboard box. If I had a glass boat, I would not use this location since it's too low for my taste. And above all, it's too far aft - considering that I go aft of the mainsheet each time I tack, and that the further aft I go, the more transom drag I get.

I have just jotted this down off the top of my head more or less. Your critique, questions and/or suggestions for improvement will be welcome c/o Uncle Al.