Knots, Bends, and Hitches — Choosing the Right One Under Load

What the rule requires

Every question on this topic is a selection question dressed as a situation, and the three-way split decides which options are even in play. A knot forms an eye or secures a line to itself; a bend joins two lines together; a hitch secures a line to a spar, ring, or another line NAVEDTRA 14067 §3-2. When the stem says you must make two hawsers into one, the correct answer is a bend, whatever the distractors are named.

The working repertoire is the eight basic knots: bowline, clove hitch, cleat hitch, sheet bend, square knot, figure-eight, rolling hitch, and anchor bend USCG Boatswain Manual Ch. 1 §1.3. Knots are tied where the gear must be inspected and cast off after it has been loaded; splices are stronger and permanent.

The job each one does

Bowline — forms a fixed, non-slipping eye in a line's end, and is the workhorse for dropping a loop over a bollard or around an object; it does not slip, yet unties easily after loading .
Square (reef) knot — ties two lines of equal size for light duty, or secures a furled or lashed object. It is not trusted for joining two lines under strain, and it jams under heavy load.
Sheet (becket) bend — joins two lines, especially of unequal size, and holds better than a square knot.
Clove hitch — secures a line to a spar or rail and is quick to make, but it can work loose under a varying pull, so it is commonly backed with a half hitch.
Two half hitches — makes a line fast to a ring or post.
Rolling hitch — takes a strain along a spar or onto another taut line, which is what makes it the hitch for stoppering off a line that is under tension.
Figure-eight — a stopper knot, to keep a line from running out through a block.
Timber hitch — for hoisting or dragging a spar.
Cat's paw — for hooking a line to a hook.

A good knot is easy to tie, holds under the load intended, and can be cast off when needed. The seaman chooses the knot for the job, and does not overload a square knot where a bend or a bowline is called for.

A messenger has to be bent to a hawser of much larger diameter to haul it across. Which do you make up?

A sheet (becket) bend. It is the bend for joining two lines of unequal size and holds better than a square knot, which is for equal-size line in light duty only.

Splices hold what knots give away

A splice joins lines or forms a permanent eye by interweaving the strands, and a properly made splice retains most of the line's strength, far more than a knot, which weakens a line at the bend NAVEDTRA 14067 §3-3. That single sentence answers any question phrased as "which method retains the greater percentage of the line's strength."

The three splices in three-strand laid rope divide by what the finished line has to do:

Eye splice — a permanent loop in the end, usually around a thimble to protect the eye from chafe. Strands are unlaid and each tucked over one and under the next, against the lay, for at least three full tucks, and more than three in synthetics because they are slippery.
Short splice — joins two lines permanently and strongly, but leaves a thickened section that will not pass through a block.
Long splice — joins two lines while holding nearly the original diameter, so the line still renders through a sheave; it costs some strength and more rope.
Back splice — finishes an end against unlaying, and thickens it.

Where the end is only to be kept from fraying, it is whipped, either with a plain whipping or the more secure palm-and-needle whipping, using small stuff such as marline or whipping twine. On inspection, an eye wants enough tucks and a sound thimble, and a whipping wants to be tight and not slipped back from the end.

What the line is made of changes the answer

Manila, sisal and hemp have moderate strength, hold knots well, and give clear warning before failure, but they rot if stowed wet and are weaker than synthetics NAVEDTRA 14067 §3-1. Natural fibre is dried before it is stowed for exactly that reason.

Nylon is very strong and elastic, which is what recommends it for mooring and towing since the stretch absorbs shock; the same elasticity makes it recoil dangerously if it parts, and it loses some strength when wet. Polyester (Dacron) is strong with much less stretch, for work where low stretch is wanted. Polypropylene is light and floats, and is cheaper, but weaker and degraded by sunlight. Small-vessel practice runs predominantly on nylon and polypropylene, with wire rope kept for standing rigging and heavy-load work USCG Boatswain Manual Ch. 1 §1.1.

Laid rope is fibres spun into yarns, yarns twisted into strands, and usually three strands laid up together, most often right-handed; braided rope has a braided cover, sometimes over a core . Right-laid line is coiled clockwise, with the lay, or it kinks. Keep line clear of oil, chemicals and sharp edges, protect it with chafing gear where it bears, and inspect for external wear, cut or pulled strands, and internal powdering found by opening the lay. Retire line that is badly chafed, has broken or fused strands, or is stiff and discoloured from age or chemical attack.

Wire rope work

Wire rope goes where high strength and low stretch are needed: standing rigging, boat falls, cargo runners and towing gear NAVEDTRA 14067 §3-4. It is spliced with a marlinespike and heavy tools, or the eye is made up with a swaged or poured (spelter) socket .

A kink is the damage wire does not recover from: once a kink is pulled taut the wire is permanently distorted and weakened . Unreel and coil so turns are neither forced in nor out, by rolling the reel or using a turntable rather than throwing off loops. Keep wire off sharp edges and small-radius bends, and keep it clean and lubricated so the wires slide over one another and internal corrosion is prevented. Before cutting, put seizings on both sides of the cut so the strands cannot fly apart. Running wire is retired for broken wires counted in one lay length against the limit, reduction in diameter from wear or a wasting core, corrosion and pitting, birdcaging, kinks, crushing, or heat damage. Wire is stronger than fibre of the same size but gives less warning before it fails.

A temporary eye in wire is made with wire-rope clips, and they are fitted with the saddle on the live or standing part and the U-bolt on the dead end — never saddle a dead horse — in the correct number and to the correct torque NAVEDTRA 14343 §8-3. A thimble in the eye protects the rope from chafe at the connection. Shackle pins are moused and turnbuckles locked so gear does not work loose under vibration and load reversals.

Telling it apart

Joining two lines: square knot against sheet bend

The criterion is whether the join will carry a working strain, and whether the two lines are the same size NAVEDTRA 14067 §3-2.

Square (reef) knot — equal-size line, light duty, or securing a furled or lashed object. Most often misfiled as the answer to "join two mooring lines," where it is wrong on both counts: it is not trusted under strain, and it jams under heavy load.
Sheet (becket) bend — any join, and the only one of the two rated for lines of unequal size. Misfiled as "only for small stuff," when it is the general-purpose bend.

Making fast: clove hitch, two half hitches, rolling hitch

The criterion is what the line goes around and which way the strain comes on.

Clove hitch — around a spar or rail, strain athwart the spar, quick to make; it works loose under a varying pull, which is why it is backed with a half hitch.
Two half hitches — to a ring or post.
Rolling hitch — strain along the spar, or onto another line that is already taut. This is the hitch in any stem that says a line is under tension and must be stoppered off.

Short splice against long splice

The criterion is whether the spliced line must still render through a sheave NAVEDTRA 14067 §3-3.

Short splice — stronger join, thickened section, will not pass through a block.
Long splice — nearly original diameter, passes the sheave, at the cost of some strength and more rope consumed.

Working a question

You are shifting a nylon mooring line from the warping head to the bitts. The line is under strain and must be stoppered off first. Which do you use? A. Clove hitch on the standing part B. Rolling hitch on the standing part C. Square knot to the standing part D. Figure-eight in the bitter end

Name the job. The stopper is being made fast onto another line, not onto its own end and not to a fitting. That puts it in the hitch family and rules out any option that forms an eye or joins two ends.
Read the operative condition in the stem. The line is under tension, and the strain runs along it. The rolling hitch is the hitch that takes a strain along a spar or onto another taut line, which is what stoppering off is NAVEDTRA 14067 §3-2. B is the answer.
Kill A on the condition, not on feel. A clove hitch is quick, and on a rail it would serve, but a stopper on a mooring line sees a varying pull as the load transfers, and that is the condition under which a clove hitch works loose.
Kill C on category. A square knot ties two lines of equal size for light duty. It is not trusted under strain and jams under heavy load.
Kill D on function. A figure-eight keeps a line from running out through a block. It grips nothing.
Then work the deck. Stand clear of the bight and out of the snap-back zone, because a loaded line that parts whips its ends back along its own lead with lethal force NAVEDTRA 14067 §4-1. Surge the line around the bitts to take the strain gradually rather than cleating it hard; a line that can be eased is a line that does not part.

For the transfer itself, the line is made fast with a round turn on the after bitt and then figure-eights across both bitts, finished so it can be surged or slipped.

Where candidates lose the point

Choosing the square knot to join two lines of different size. The stem says "join two lines," the candidate remembers the square knot joins two lines, and stops reading. Equal size and light duty are both part of the rule; unequal size sends you to the sheet bend, and strain sends you there as well.

Treating a knot and a splice as equivalent. A splice retains most of the line's strength; a knot weakens the line at the bend. Any option offering a knot as the way to preserve strength is wrong on that ground alone.

Answering "three tucks" for a synthetic eye splice. Three full tucks is the floor for laid rope. Synthetics are slippery and take more than three, so an option specifying additional tucks for nylon is the better answer, not an over-careful one.

Reaching for the short splice on a cargo runner. The short splice is stronger and simpler, and that is what attracts. The thickened section will not pass through a block, so a line that must render through a sheave gets the long splice.

Fitting wire clips with the saddle on the dead end. The distractor reads plausibly because both parts of the eye look alike. Saddle on the live part, U-bolt on the dead end.

Coiling right-laid line counter-clockwise. Right-laid line coils clockwise, with the lay. Against the lay puts kinks in it, and in wire a kink pulled taut is permanent damage.

Believing the danger is only at the fitting that let go. The ends of a parted line whip back along the line's lead, so hands never stand in the bight, never stand in line with a line under strain, and stay out of marked snap-back zones.

Check yourself

You must put a temporary eye in a mooring line to drop over a bollard, and it will have to come off after the line has been loaded hard. What do you tie?

A bowline. It forms a fixed, non-slipping eye and unties easily even after loading, which is exactly why it is preferred to a splice where the eye is temporary NAVEDTRA 14067 §3-2.

A three-strand nylon line has parted and must be made up permanently so it will still pass through the block on the cargo whip. Which splice?

The long splice. It keeps nearly the original diameter so the line renders through the sheave. The short splice would be stronger, but its thickened section will not pass a block NAVEDTRA 14067 §3-3.

You have hitched a line to a stanchion with a clove hitch and the pull on it will surge as the boat works alongside. What is the deficiency and the remedy?

A clove hitch can work loose under a varying pull. Back it with a half hitch.

Which is correct: a line is "made fast" to bitts by taking a round turn on the forward bitt, or on the after bitt?

On the after bitt, then figure-eights across both bitts, finished so the line can be surged or slipped NAVEDTRA 14067 §4-1.

You are to cut a length of 6x19 wire rope on deck. What do you do before the cut?

Apply seizings on both sides of the cut so the strands cannot fly apart NAVEDTRA 14067 §3-4.

Which line would you choose for a mooring line where shock loading is expected, and what is the hazard that comes with it?

Nylon. Its stretch absorbs shock, which is why it is used for mooring and towing, but it recoils dangerously if it parts and loses some strength when wet NAVEDTRA 14067 §3-1.

An eye is being made up in wire rope with clips, and you find the saddles bearing on the bitter end. Accept or reject?

Reject. The saddle goes on the live or standing part and the U-bolt on the dead end, in the correct number and torque NAVEDTRA 14343 §8-3.