Join Date: Dec 2008
Location: North Carolina
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There's lot more to lines than just nylon and polyproplene. Get a copy of West Marine's catalog and look at what they offer and the advice that they give. Polyproplene (in general except where you want a floating line such as a ski rope) is a horrible line for boats...little shock absorbing stretch and deteriorates extremely fast (i.e. looses its strength) when exposed to sunlight. There are two basic lines for boating today .. first is nylon for dock lines and anchor rodes...strong, elastic to absorb shock. Comes in several make ups with three strand or double braided mosty common. Both stretch, but double braid stetches less but stays more flexible so it's easier to handle. Either one works for dock lines. If you are in a rough spot, be sure to have extra lines of a suitable size. Working load of lines is normally about 15% of breaking strength. Chafe, not line strength is going to be your worry, so protect the line anywhere the line will rub on something or take a sharp turn around an object. Polyester has comparable strength to nylon but less stretch...there are lots of variations by manufacturers to get less stretch for halyards, so don't use these for dock lines (except in severe storm conditions as backups to nylon lines when you have no other lines ...and then use them slacker than the nylon lines. There are a whole range of new exotic new special application line types that have been developed for halyards and other applications where very high strength and very low stretch is desired....these lines are extremely expensive and usually of little concern for the average, non racing sailor. None are suitable for dock lines. Stay away from the cheap "poly" lines that are also sometimes labeled nylon that are sold in some non boating stores...most short cut the manufacturing steps needed for good line and often use significant amount of polyproplene....which looses strength in sunlight.
Last edited by NCC320; 07-20-2009 at 08:29 AM.