I know what those are... and have used them in other areas. WM sells them. Yeah, it is something like that at the end of the halyard.

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=888651&catalogId=10001&langId=-1&storeId=11151&storeNum=50045&subdeptNum=50046&classNum=50051#.UoKL2uL6Wz4

OK but the reason I had to laugh is I was looking at the location of the snatchblock in the pic, and the lines you have running through it... and the angles seemed all wrong... then it dawned on me... oh yeah, this guy has more boat OUTSIDE the lifelines... D'OH! Nice trick.