The bowline knot is a very versatile knot that is perfect for sailing. It's fast, simple, and is commonly used to attach jib sheets to the jib's clew.
While not the most common knot, the Spanish Bowline is useful for towing and can also be used as a makeshift bosons chair for rescues, as the two loops can be placed around the legs.
Figure 8 Loop
Figure 8 loop knots are generally used to carry light to moderate weight, and are useful for climbing. Its figure 8 shape (where the knot gets its name) is very secure, but may become hard to untie.
The alpine butterfly is primarily a climbing knot, but can also be used with anchors. This knot is unique in that it can be loaded three different ways (each end and through the loop), and is considered one of the strongest and most reliable knots.
This is a very handy knot to use to tie together the ends of two ropes, and is very popular in boating. In sailor terminology, a sheet is a rope or chain used to hold a sail in place, and bend means to tie. Boat donations may have this type of knot on their ropes in order to conserve rope.
This knot, similar to the sheet bend, is used to join two ropes together. However, this knot is much stronger and will not jam even when wet, which is especially important for boating. Its interwoven shape makes it aesthetically pleasing, though it is surprisingly simple to tie.
This knot is very easy to tie and is considered to be a very secure double-looped knot.
The clove hitch is one of the most standard knots, and is the basis for many other types of knots. However, it should be noted that while it is a common and useful knot, it is not the most secure when used as a binding knot and is not recommended for boating.
The anchor bend, also know as the fisherman's bend, is the best knot to use when attaching an anchor to an anchor line, and is commonly used for warping.
A buntline hitch is a secure knot to use when attached rope to an object. It's a very old sailing knot and was originally used to secure buntlines to the foot of the sails.
This knot is a very popular boating knot that's commonly used to secure a rope very tightly to an object. Its an extremely tight knot and can only be easily removed if the knot is slipped.
The highwayman's hitch is a quick-release knot that is meant to be untied very easily. Legend says that it got its name from the type of knot robbers (called "highwaymen") used when they had to tie their horses to a carriage while they were looting - great for a quick getaway.
Heaving Line Knot
This knot has a very heavy end, which is useful for throwing (or heaving!) when you need to transport a rope (for instance, from ship to ship).
Overhand Knot & Double Overhand Knot
The overhand knot is a very common knot and is generally used as a stopper knot. The double overhand knot is similar to the regular overhand knot, and from there multiple overhand knots can be created.
The rolling hitch is an extremely versatile knot that is used to attach rope to rods. It's a friction hitch, and is designed for lengthwise movement. Its most common use in sailing is to rig a stopper so that the tension of a jammed winch or block can be cleared.
This is another common knot, and is used to climb masts. It's an interesting knot because it allows the rope to slide, but when heavy weight is applied, it tightens. It is named after its inventor, Dr. Karl Prusik, who used it for rope ascending when mountaineering.
The kleimheist is very similar to the prusik, but is more easily removed and can be released by loosening the loop at the bottom. More loops can be added to increase friction