Knots, as a way of joining rope without special equipment, are useful in many situations. On a sailboat, knots are essential both for daily use and for emergency repairs. This instructable describes several different common knots:, e.g.
Sheet Bend - to tie two lines together
Bowline - to make a loop
Reef Knot - to fasten a bundle of material
Fishermans Bend - to secure a line to a post or ring
These knots are good for regular rope - braided or 3-strand polyester or natural fibre (hemp, sisal). Monofilament (fishing line) or steel cable performs better with different knots.
Knots are typically quite a lot weaker than straight rope - when rope goes around a tight radius, such as in a knot, the outside is under more tension than the inside. Splices (which require special tools, and are time-consuming to make) are stronger, so permanent fittings usually have eye-splices
Step 1: Sheet Bend
The strain is taken on the ropes in the middle - not the one coming out the side.
How the knot is made is not critical - it is the final shape that is important. One can make the flat loop first, and work the other rope around it. Or one can make the crossed loop first - required when tying a bowline.
The two images show front and back views of the same knot
Easy to make
Easy to undo when tension is removed
Does not easily capsize
Hard to make under load
Dangerous to make under heavy load
Joining two equally-sized ropes
Extending a towline or stern line
Method 1: the same as a bowline
Method 2: starting with the flat loop
Step 2: Double Sheet Bend
The load goes on the line through the flat loop, not the one that comes out the side of the knot.
Securing a heaving line to a tow line
Extending a stern line if you don't have enough line of one thickness
Step 3: Bowline
The photos show the completed loop, and closeups of the front and back of the actual knot. Note that it is the same as the sheet bend - but it must be made the right way round. This loop does not tighten in use. The knot is quite easy to untie once the load is removed. With practice, it is very quick to tie.
Securing a dinghy line to a railing or stanchion
Securing an anchor line to an anchor
Tie a jib sheet to the sail
Tie a mooring line around a rock or tree
Tie a float to an anchor tripline
Use one in each line to tie two ropes of very different sizes - e.g. a throwing line to a large tow rope
Disadvantages: the knot must be completely made before it will take any strain - it is hard to tie if there is already a load on the rope
Step 4: Bowline on the Bight
A bowline "on the bight" is a bowline tied in a loop of rope (neither end is needed). The shape is the same as a bowline made with a double line, but the middle of the bight forms the loop around the standing part.
An impromptu bosun's chair - to sit in while being transferred between two boats at sea
Step 5: Clove Hitch
Securing a burgee pole to a burgee halyard (a continuous loop of thin line)
Securing a tiller from swinging
Step 6: Round Turn and Two Half-Hitches
Can be made under load - it is easy to take turns around the bar while maintaining tension on the rope
Strong - provided the bar is thicker than the rope, the rope is not weakened by sharp bends.
The end tends to work loose
Securing a line to a mooring ring or samson post
Step 7: Fishermans Bend
Secure against working loose
Hard to make under tension
Hard to undo under tension
May seize up under load when wet, making it hard to undo
Securing mooring line to ring
Securing fender lines to rail
Step 8: Studsail Bend
The studsail bend is like the fishermans bend, but the second hitch is also secured under the round turn, making it even more secure against working loose when under tension
Very secure against working loose
Hard to make under tension
Hard to undo under tension
Step 9: Figure-8 Knot
The double figure-8 knot is used in rock climbing, as an alternative to a bowline, to secure a climbing harness to the end of a safety rope. The double knot is made by making a single knot, then tracing back around the knot with the free end after passing it around the harness loop.
Easy to verify by inspection
Not prone to work loose
Slow to make and undo
Cannot be made under load
Step 10: Prussic Knot
The prussic knot may be used as a climbing ascender - when made around a vertical rope as shown, downwards tension on the ends locks the knot, while release of tension allows it to be slid up the rope. A pair of prussic knots on foot loops may be used in tandem to climb a rope.
Climbing a rope
Taking up tension to free a riding turn on a winch
Step 11: Reef Knot
It should not be used to make a loop, unless it can be tensioned around a solid object. It should not be used around a person - use a bowline instead. A capsized reef knot will slip easily and could constrict and cause severe injury.
Reefing a sail (tying the unused portion around a spar)
Securing a furled sail to a spar (sail ties)
Wrapping a parcel
May be made under moderate load
Capsizes (works free) if used improperly
Can seize up under load when wet
Tying the knot:
Capsizing a reef knot:
Step 12: Cleats
This is not a knot, but is very common on boats.
The first picture shows a rope cleated normally. The second shows one with a final locking turn - the last turn is twisted before placing over the cleat so that the tension on the rope helps secure the free end.
When working with ropes under tension, take a turn or two around a winch or cleat before trying to secure the end with a knot. The load on the free end falls exponentially with each turn taken. Severe injury can result if a finger or other body part is caught in a loop of rope, or between a rope and another object.