Synthetic shackles, line grippers ( http://www.ahoycaptain.com/shop/shockles_LineGrabber.html ) that are good for snubber and bridle attachment, removable forestays and baby stays such as Paul is using (much easier to handle), and running backstays. I don't envision the average crab crusher using this for rigging, but for faster boats and multihulls seeking to reduce weight aloft it makes sense.

In fact, any boat that has a C-F mast is paying 3-5x the cost of an aluminum spar to save weight aloft -- so is a possible candidate for synthetic standing rigging. The 7/16 Amsteel I'm planning to use is 0.041 pounds per foot vs. 0.21 pound per foot for stainless 8mm 1x19 wire rope. In other words, 100 ft. of 7/16 Amsteel is 4.1 pounds vs. 21 pounds for steel. So even though I'm up-sizing and doubling the strength the synthetic is roughly 20% of the weight, saving about 16 pounds aloft.

If you don't think that's going to affect boat performance try holding 16 pounds next to your body, then hold it at arms length (if you can), then attach it to a 50 ft pole and try holding it out at any angle.