There are few things more important on a boat, especially a sailboat, than properly used and cared-for line. To dock or moor a boat, to set an anchor or a sail, to attach a fender, lengthen lines — all of these unavoidable processes require some knowledge of line handling and, of course, of knots.

If you are just starting on your path to becoming a mariner, check out our guide to the most essential knots that every boater should know. If you have already mastered these, however, and are looking to learn more about how you can use lines on a boat, keep on reading! Below is a guide to five more advanced boating knots that are used in more specialized situations than the ten in our first guide. These knots are all part of what is called marlinespike seamanship — the knowledge and skills to work with rope in all its forms and uses aboard ship.

You may notice that although all of the following are knots, some have the designation "hitch" or "bend." In technical terms, a bend is a type of knot that is used to fasten a line to another line or to a spar, while a hitch is used to attach a line to an object such as a cleat or ring. Another type of knot not mentioned in this guide is a splice, which is the method used to permanently attach two different lines or mend a snapped one. Nowadays, with the widespread availability of rope, many boaters prefer to replace a line rather than to repair the old one.

The Sheepshank Knot

For temporarily shortening a line, when taking up slack or securing a load to a truck or trailer, a sheepshank may be the way to go. Make sure to remember that this is only a temporary measure, and the knot will not withstand large amounts of pressure. It was mainly used before the advent of today’s more slippery synthetic ropes, and may come undone if tied with them. Once it is not under tension, it is easy to undo.

The Double Bowline

Thanks to its grace under pressure and its ease of release, the bowline is one of boaters’ best-loved knots. Sometimes, however, a slippery synthetic line can cause a bowline to come undone, or perhaps you just want to make extra sure that your knot is secure. The double bowline uses an extra turn in its construction, so that the knot is twice as strong as it would be otherwise.

The Rolling Hitch

This knot is useful for tying a small line to a larger line. If you need to haul on a line or tie down an awning, the rolling hitch is the right knot for you. It is also useful for tying a small line to a pole of wood or some other material, as this is the knot that is least likely to slip.

The Carrick Bend

The carrick bend is best used for tying lines of the same size together. Do not be alarmed if the knot changes shape once pressure is put on it — this is natural for this type of knot. It is best used for stiffer, heavier lines where a square knot may not be durable enough.

The Monkey Fist

Although used more widely in the past as a way to weigh the end of a line thrown from boat to dock or boat to boat, the monkey fist is now used for more decorative purposes. If you are looking for a challenging knot, or a way to while away a few hours at sea, the monkey's fist can be quite impressive upon completion. This knot was also used as a weapon by sailors of old in tavern and street bawls.

The Surgeon's Knot

Sometimes when tying a square knot, the first turn will begin to loosen as you tie the second, meaning that you either need someone to help you hold the knot in place as you tie it, or that your knot will be too loose. The surgeon's knot is an answer to this problem. It uses two turns at the start, as opposed to one, so the first part of the knot will hold against tension as you tie the second.

As you start becoming more familiar with knots and other uses of line aboard a boat, there are some specific terms that you can use to help yourself along the way and to educate others.

Standing part refers to the long end of a piece of line.

A bight is when the working end of the line is looped back on itself in the course of tying a bend, hitch, splice, or other knot.

A bight that goes around the rope or another object is called a turn.

The very opposite end if a line you are tying a knot in is called the bitter end.

Now that you have read this guide and understand more of the terms and uses of knots, it is time for the most important part of the lesson — practice. No knot is truly learned until you can tie it without thinking at the moment it is required. With that in mind, take out some practice rope whenever you get the chance. With each knot you get down, you will be taking greater control of your boating experience. Good luck, and happy knotting!