you decide to purchase docklines, it is possible to be overwhelmed by
the variety of rope available . If you are after rope to secure your
boat to the dock, you can - and should - ignore most of those spools.
Most marine cordage is for general or specialized use aboard
sailboats, and the less it stretches, the more it gets revered by
sailors. For docklines, however, sailors and power boaters alike need
a rope that does stretch.
Nylon has three characteristics that
make it ideal for dockline. It is incredibly strong, it is very
stretchy, and it resists the harmful effects of sunlight.
The value of strength is
self-evident, but the benefits of elasticity may not be as obvious.
When your boat surges against an unyielding dockline, the load on the
line goes from zero to the maximum at the instant the line becomes
taut. The likely consequence is a broken line - not unlike how you
might snap a piece of thread with a jerk. Even if the rope is strong
enough not to break, it is hammering cleats and bitts with every
surge. Nylon doesn't become taught suddenly, but dissipates the load
by stretching. It is like the difference between hitting the steering
wheel or hitting the air bag in an accident.
As for nylon's resistance to
ultraviolet damage, docklines - particularly permanent docklines -
live in the sun. Nylon enjoys a much longer life in that environment.
Nylon actually has a fourth
characteristic that you will surely appreciate; it's less expensive.
The only exception is polypropylene.
Polypropylene rope is stiff, very
slick, and usually bright yellow; but it's most distinguishing
characteristic is that it floats. You will be familiar with this rope
if you water ski. Polypropylene has a relatively low breaking
strength, the quality of the rope is notoriously erratic, and because
it is so slick, it does not hold a splice.
Braid or 3-strand?
Nylon rope is available in both
braided and 3-strand twist construction. Each has its advantages.
Nylon braided line looks "dressy". It has better abrasion
resistance than 3-strand nylon, and
typically is slightly stronger. Braided line can be a good choice for
tying up in your home dock, but because braided lines have a tendency
to snag on rough pilings, it is not recommended for traveling
docklines. As anchor lines, however, braided nylon handles easier and
stows more compactly and with less of a tendency to tangle, but at the
cost of some elasticity.
The main advantages of 3-strand
nylon for docklines are that it doesn't snag, it is easy to splice,
and it is considerably less costly than braided rope. 3-strand also
has the significant advantage of being more stretchy than braid. As a
practical choice for docklines, 3-strand nylon is unbeatable, and how
often is the best also the least expensive?
Since larger diameter line takes
longer to chafe through, a case might be made for selecting the
largest diameter that will fit your cleats. But as the line diameter
gets larger, it also becomes less elastic - making the "right" line
diameter a bit of a catch-22. The line diameters shown in the chart
should deliver both sufficient strength and the beneficial effects of
For docklines that are a fixture of your permanent
slip, work out the appropriate lengths using old line - making
allowances for eye splices.
Nothing is more convenient than pulling into your slip and simply
drooping eyes over the mooring cleats. If your dock is fixed - not
floating - be sure to leave a little extra length for unusually low or