Lifelines - proper hand-swaging & meeting PIYA category II
If you're doing any kind of refitting (in this discussion - the lifelines) and you're interested in racing the Around Admiralty, then be sure to check the PIYA website to dowload their category certificate. Admiralty boats are supposed to meet Category II level specifications. (http://www.ussailing.net/piya/PIYA/2009%20PIYA%20Certificate.pdf)
The PIYA spec on lifelines (section 3.16) requires a Cat. II boat to have uncoated SS wire rope lifelines installed. I went with 3/16" diameter 7x19 wire (seven strands of 19 wires per strand) because it's more flexible, nearly same strength as 7x7, and in case of 'meat hooks', the wires are smaller and will do less damage. Just my thought process on this. Depending on what resource you've got, the Breaking Strength (BS) of this wire ranges from 3300-3400 pounds. According to PIYA section 3.16b, the minimum BS of your wire must be no less than 3700 #'s. So there's room for some mild interpretation here, but I would assume that being in the neighborhood would be good enough. Had I looked at my copy of Ian Nicholson's Boat Data Book prior to purchasing, I would have gone with 7x7 wire since it comes in right at 3700 #'s BS.
And to confuse things, PIYA recommends that you use 1x19 wire - typically only used for high-strength standing rigging. I would argue that this is unnecessary and might even be a bad idea since any high strength steel component will be less flexible and more fatigue prone.
If you're really happy with the measurements of your lifelines, and you're confident that you can transpose this information over the phone with a rigging shop down south, then have your lifelines machine swaged in a shop. If you're like me and you've screwed up phone/internet orders several times, then just order the hand-swage fittings and do the work yourself. I did half of my lifelines this evening in about an hour, and I could do all the work on the dock and "measure twice, cut once". The Johnson Rigging Company pretty much has a monopoly on hand-swaging fittings for SS wire rope. Use their hand-swage tool, not the "Swage-it" multipurpose swaging tool. Johnson designed their tool to work with SS fittings, while "Swage-it" is only designed to work with Nicopress-type fittings that are typically soft metals (nickel-plated copper or aluminum).
One thing most people neglect when they do a hand-swage job, is checking to make sure that you crimped the fitting correctly. Johnson's website has a free download of the swaging instructions, complete with approved caliper readings & a graphic of where to take the finished crimp measurement. http://www.csjohnson.com/PDF/instructions/53-215_HC.pdf
A word on Stainless: 304/306 is an alloy that has higher resistance to corrosion - something desirable for a boat in warmer climes. It's not as strong as the other SS alloy - 316, and it'll cost you more.
So until the PIYA lets us use the Dyneema's, Spectra's, or Vectran's that's as strong or stronger than steel and more comfortable to lean against, Cat. II specs will require the installation of uncoated wire rope.