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Know The Ropes

Published By: Heather Robertson

Like most other things, ropes come in a variety of types and styles; some of them are highly suited to different boating applications, while others will give you nothing but grief. Taking a few minutes to learn the differences between various kinds of lines will allow you to choose wisely, not only making your time on the water far more enjoyable, but potentially saving your boat from damage and keeping you out of embarrassing or even dangerous situations. Ropes are made from a wide variety of materials, but the most common are manila, polyethylene, polypropylene, nylon and polyester. Each material has its own pros and cons. 


With its dull brown colouration and hairy appearance, Manila rope is fairly easy to spot.A hard, natural fibre, manila rope is strong, doesn’t stretch much and holds knots reasonably well. And as a natural fibre, it won’t melt when subjected to heat or friction as synthetic ropes will. It’s also surprisingly resistant to sunlight.   The downside to manila — and it’s a big one –— is that it must be stored dry to avoid mildew. Put it away wet and it will deteriorate quickly. Exposure to chemicals like oil or gasoline accelerate that process. Accordingly, manila rope (along with sisal rope, made from a similar but slightly weaker fibre) has been largely replaced by synthetic products for use on boats. You still see it around, but most often because the buyer simply didn’t know any better.    


Often sold at gas stations and discount stores, polyethylene rope is relatively inexpensive stuff. It’s generally the number one choice among retailers who need to meet a certain price point. In other words, it’s cheap.   Accordingly, polyethylene rope is most often made in comparatively small diameters that limit its suitability for boating applications. Most often, you find it used for ski rope and other light-duty, utilitarian purposes. Picture it tied to an anchor someone made by pouring cement into an old paint can.   One of the big knocks against polyethylene is that it tends to kink easily, making it prone to tangles. And God help you if you accidentally get a fishing lure snagged in it. Even pliers won’t help.   Polyethylene rope has a place, but if you need line that can do more than just hold your canoe over a good walleye spot, you’ll want to consider some other alternatives.    


Likely the most widely used type of rope on Canadian lakes and rivers, polypropylene rope is also relatively inexpensive and is available in a wide variety of sizes, in both three-strand and full-braided versions.   The fact polypropylene rope floats like a cork makes it perfect for a number of boating applications. For example, it’s an ideal choice for ski-tow ropes, or for heaving lines. It’s also perfect for securing tenders or dinghies, since excess line that falls into the water isn’t likely to become snarled in the boat’s propellers. Polypropylene rope doesn’t absorb water, doesn’t shrink when it’s wet, holds knots securely and remains flexible regardless of the temperature. These are all good qualities, so what’s the catch?   The two big strikes against polypropylene are that it’s not terribly strong compared to other materials, and it doesn’t have much stretch. A polypropylene rope of a given diameter is only about half the strength of a similar nylon or polyester line. Combined with its relatively low elasticity, polypropylene rope will snap long before other lines will. That makes it a poor choice for high-stress jobs like anchor rope or dock lines.   Being somewhat sensitive to ultra-violet light, polypropylene rope also tends to deteriorate fairly quickly, so you’ll want to store it out of the sun. And because it has a fairly low melting point, polypropylene rope doesn’t work well in applications where it will encounter any amount of friction. The fibres will either soon abrade, or melt together, as if they were glued.    


Nylon rope isn’t nearly as widely used as polypropylene simply because it costs more. But the premium price reflects premium quality, and you really do get what you pay for. Like less-expensive polypropylene, nylon rope comes in sizes ranging from about the diameter of a pencil to about as thick as a flashlight, in both three-strand and fully-braided versions. Both varieties hold knots well and maintain their knot strength when wet. It’s resistant to oil and gasoline, so even a dunking in the bilge won’t really harm it. Between the two, fully braided nylon rope costs a little bit more, but is much easier on the hands, especially when wet. Many boaters feel braided line offers a classy look three-strand ropes simply can’t match.   Although nylon rope doesn’t float like polypropylene, it offers the kind of brute strength few other materials can match — steel cable included. And while nylon line will absorb some water, it remains comparatively elastic. This unique quality makes the stuff absolutely ideal for high-stress applications, like towing or for use as dock lines. Nylon has an extraordinary ability to absorb impact from a boat rocking in the breeze or bouncing from careless wakes, greatly minimizing strain on the boat’s cleats. It offers tremendous weather and abrasion resistance too, so it can take a beating day after day without losing its shine.  


Once the darling of 1970s fashion designers, polyester has moved on and found its niche with rope manufacturers. You’ll never find it at the discount store, but upscale chandleries and marinas catering to discriminating clientele sometimes stock polyester line – truly the Rolls Royce of ropes. You can usually spot the stuff by price alone, as it’s brutally expensive compared to other types.   Polyester, as you may recall, is an ultra-low stretch, ultra-high strength fibre (especially the pre-stretched varieties) that remains pliable regardless of temperature and doesn’t shrink when it gets wet. And, it offers remarkable abrasion resistance. Those qualities make it an ideal choice for truly punishing applications, like anchor rope or sailboat rigging.   But polyester’s lack of elasticity makes it a lousy choice for dock line, since any stress from wind or wakes will transmit directly to the boat’s cleats. It’s also a poor choice for applications where it will be subjected to any kind of shock, such as towing another disabled boat.    

High Modulus Polyethylene

Remember those cheap polyethylene ropes from the discount store? Meet their steroid-enhanced second-cousin – high modulus polyethylene, which is ounce-for-ounce the strongest, toughest fibre in the world.   Known by a host of trade names including Dyneema and Spectra braid, high modulus polyethylene fibre is all the rage these days with professional tournament anglers, since fishing lines made from the stuff offer unmatched strength and abrasion resistance, yet are so thin the fish can’t even see them. Weave the stuff up to boat rope diameter and you have a line strong enough to tow a Greyhound bus.   High modulus polyethylene rope looks like a giant hunk of sewing thread, and is noticeably slippery to the touch. It remains pliable over a fantastic range of temperatures, while its abrasion resistance and wet knot strength is significantly higher than anything else known to mankind. It absorbs very little water and it doesn’t shrink when wet. If you want the absolute best, this is the stuff. Don’t look for it as a stock item in your local marina, though. You’re in special order territory here, and you’ll probably need a second mortgage to pay for it.    

Rope Care

No matter what type of rope you use, be sure to check it periodically for nicks, knots, frayed spots or kinks, all of which can seriously impair its strength. Polypropylene ropes are particularly susceptible to fraying and surface cuts, especially when frequently scraped across rocks or aluminum gunnels. Replace any suspect-looking ropes before they cause you problems.   It's usually a good idea to carry some extra rope someplace onboard. That way, should a rope snap while you’re on the water, you’re able to replace it right on the spot.     Twisted or Braided?   Ropes come in two basic styles — twisted or braided. Twisted rope is formed by coiling three individual strands together in the same direction, and opposite of the direction of the individual strands themselves. This keeps the rope from unraveling and prevents it from curling excessively.   Braided rope has its strands wrapped against each other in an overlapping pattern. Solid braid rope is manufactured by tightly wrapping several lengths of yarn together, and may be constructed from four, eight, 16 or 32 individual pieces (subsequently called four-, eight-, 16- or 32-plait rope). Solid braid rope is consistently firm to the touch and almost perfectly round in profile, so it passes easily through pulleys or winches.   Braided rope is also sold in hollow form, which may be spliced. Still other styles use a braided outer sleeve over a central core, which may be of solid fibres or another braided base. Known as braid-on-braid or double-braid, this style of construction is usually reserved for the strongest, most expensive materials where cost is secondary to strength.