Essential military knots every soldier should actually know
There are only about eight knots you have to own cold, and the Army already wrote down which ones. This is the short list from TC 3-97.61 (Military Mountaineering) and the Ranger Handbook: what each knot is for, how to tie it, and — the part the how-to videos skip — exactly where people screw it up. Because a bowline tied wrong isn’t “a little off.” It’s a slip knot that lets go with someone’s weight on it.
The diagrams here are schematic — they show what the finished knot is doing, not a frame-by-frame video. Learn the moves with an actual rope in your hands, and never trust a life-safety knot you learned only from a screen.
Square Knot
What it’s forTies together the two ends of a rope of equal diameter — or ties a rope off around a bundle. In TC 3-97.61 it lives in the joining-knot family. It is the workhorse for finishing off other knots and lashings, not for holding a life load by itself.
- 1Right end over left, then under — like the first move of tying your boots.
- 2Now left end over right, then under. Right-over-left, then left-over-right. Reverse the second half and you get a granny knot, which is garbage.
- 3Dress it flat: both standing parts should exit the knot on the same side as their own working end. Snug it down.
Two ways people ruin it. One: they tie a granny knot (same twist both times) — it slips under load and jams so hard you cut it off. Two: they use it to join two ropes of different diameters, or as a critical load-bearing bend. The square knot capsizes — it rolls into a slipping pretzel — the moment the loads get uneven. Doctrine is blunt about this: it’s a finishing knot. If a person’s weight is on the line, you want a double fisherman’s or a retraced figure-eight, not this.
Bowline
What it’s forPuts a fixed loop in the end of a rope — a loop that will not cinch down or slip no matter how hard you load it. This is the knot for tying a rope around a fixed object, hauling something up, or putting a non-slipping loop around a person or anchor. TC 3-97.61 lists it among the special knots for exactly this reason.
- 1Make a small overhand loop in the standing part — that's "the hole." The tail is "the rabbit," the standing part above is "the tree."
- 2Rabbit comes up out of the hole, around the back of the tree, and back down into the hole.
- 3Pull the standing part to seat it, then dress it and finish with a backup — an overhand or half hitch in the tail around the standing part. Every serious reference wants that safety on there.
This is the one that actually kills people, so read it twice. A bowline tied with the loop the wrong way — rabbit going around the tree the wrong direction — isn’t a bowline. It’s a slip knot that looks right, holds while you inspect it, and then runs when someone’s full weight comes onto it. The other failure is leaving it undressed with no backup: a clean bowline can shake itself loose under repeated on-off loading (climbing in and out of tension). Tie it, then tug-test it hard and confirm the tail exits inside the loop. No backup knot, no trust.
Round Turn & Two Half Hitches
What it’s forAnchors a rope to a fixed object — a post, a tree, a picket, a beam — under tension. The round turn carries the load and the friction so you can hold the strain while you tie off; the two half hitches lock it. TC 3-97.61 puts it in the anchor-knot family, and it's the knot you reach for to build a fixed anchor fast.
- 1Take a FULL round turn — the rope goes completely around the object, twice, not a single pass. Those wraps are doing the real work.
- 2Bring the working end across the standing part and tuck it through to form a half hitch.
- 3Do it again the same direction — second half hitch — and dress both hitches snug against the standing part.
People skip the “round” part and take a single turn — now there’s no friction wrap holding the load and you’re fighting the full tension with your hands while you tie. The second classic screw-up: two half hitches tied in opposite directions. Matched hitches form a clean, secure clove-hitch-style lock; opposed ones (a “cow hitch” finish) sit ugly and can creep. Same wrap direction both times, dressed tight.
Clove Hitch
What it’s forA fast, adjustable hitch for fixing a rope to a round object — a post, a rail, a carabiner. Great for the middle of a rope and for anchors you'll tension and re-tension. In mountaineering it's a go-to for clipping into an anchor because you can adjust your length without untying.
- 1Wrap the rope around the object once.
- 2Cross over the first wrap and wrap a second time in the same direction.
- 3Tuck the working end UNDER that second wrap (under the diagonal you just made) and pull both ends tight. Two turns, tail trapped under the cross.
The clove hitch is quick, which is exactly why it’s dangerous when you get lazy with it. Left loose or undressed, it slips and rolls — especially on a slick or tapered object, or when the load pulls off-axis instead of straight down. It also works loose under cyclic loading (load on, load off, repeat). It is not a stand-alone life-safety anchor knot: back it up or use it only where a failure won’t drop anybody. Fast to tie is not the same as safe to trust.
Water Knot
What it’s forTHE knot for joining webbing — tying tubular nylon into a runner or sling, or joining two ends of flat webbing. Rope knots do not hold reliably in flat webbing; the water knot is the retraced overhand that does. TC 3-97.61 specifies it for building runners out of tubular nylon.
- 1Tie a loose overhand knot in one end of the webbing. Don't tighten it.
- 2Take the other end and retrace that overhand exactly in reverse, so the second strand follows the first through every turn and lies flat alongside it.
- 3Work out all the slack, dress it flat with no twists, and cinch it down hard. Leave at least 3 inches of tail on each side.
The water knot has a nasty habit: it creeps. Under repeated loading the tails slowly work back through the knot and get shorter — and if a tail feeds all the way through, the knot comes apart with a person on it. That’s why the rule is minimum 3-inch tails and inspect it every time before you weight it. The other failure is a lazy, twisted, or loose tie — the two strands have to lie perfectly parallel through the whole knot and be cinched tight. A water knot you tied last month and never re-checked is not a water knot you should trust today.
Figure-Eight (and the Retraced Figure-Eight)
What it’s forThe plain figure-eight is a stopper that keeps a rope from running back through a device or anchor. The retraced (rethreaded) figure-eight and the figure-eight on a bight put a strong, easy-to-inspect fixed loop in the rope — the standard tie-in loop in mountaineering. It holds most of the rope's strength and, unlike some knots, you can eyeball whether it's tied right. TC 3-97.61 covers the whole figure-eight family.
- 1Figure-eight loop: make a bight, cross it over the standing part, around behind, and back down through the first opening — the rope traces a figure "8."
- 2Retraced version (to tie into a fixed point): tie a single figure-eight a couple feet up the standing part, pass the tail around the anchor, then follow the original eight back through in reverse so two parallel strands make the shape.
- 3Dress it: every strand parallel, no crossed lines, no slack. A well-dressed eight is symmetric and obvious. Leave a solid tail.
The figure-eight is forgiving, which breeds complacency. The real failure is a mis-dressed or half-traced knot — strands crossed, or the retrace not carried all the way through, leaving a shape that looks like an eight but isn’t one. The fix is the whole reason the eight is popular: you can see it. Learn what a correct one looks like and check every strand. Also leave enough tail — a figure-eight with a stub tail can invert (“capsize”) under heavy load.
Prusik
What it’s forA friction hitch that grabs a rope when weighted and slides freely when not. Made from a loop of smaller-diameter cord wrapped around a bigger main rope, it lets you ascend a rope, back up a rappel, or build a movable, load-releasing attachment point. TC 3-97.61 covers it as a core mountaineering skill — it's how you climb a rope with almost no gear.
- 1Use a loop of cord notably THINNER than the main rope (roughly 60–80% of the rope's diameter — e.g., 6–7 mm cord on an 11 mm rope).
- 2Girth-hitch the cord loop around the main rope, then feed the loop back through itself two or three more times so the wraps stack neatly side by side.
- 3Dress the wraps flat and even, then load it. Weighted, it bites; unweighted, slide it along the rope.
Diameter is everything. Cord too close in size to the main rope — or the same rope — and the prusik will not grab; it just slides, and you find that out at the worst possible moment. Too few wraps, same result. On the other end, wet, icy, or muddy rope reduces the bite, so you add a wrap. And a prusik loaded and slid at speed can glaze and melt the cord from friction heat — inspect the cord, retire it when it’s fuzzy or hard. A friction hitch that doesn’t catch isn’t a backup, it’s a decoration.
Swiss Seat (Rappel Seat)
What it’s forAn improvised rappelling harness made from a single length of rope or tubular nylon tied around the waist and thighs — no manufactured harness required. The Ranger Handbook and TC 3-97.61 both teach it as the field-expedient seat you rappel off of when all you have is rope and a locking carabiner. It exists for the situation where you have to get down and don't have a harness.
- 1Find the middle of the rope, place it at your hip, and wrap around your waist, tucking the wraps.
- 2Bring the ends between your legs, up over each thigh, and under the waist wraps to form the leg loops — snug, not strangling.
- 3Join the ends with a square knot secured by two half hitches on each side, positioned on the hip (not the front, not the spine), and clip a locking carabiner through the seat where doctrine specifies. Then have someone check it.
This is the one where “read it on a webpage” gets someone hurt, so here’s the honest version: a Swiss seat tied wrong is a fall. Tied too loose, it rides up and you invert off the rope. The square knot in the wrong place or not backed up with half hitches can capsize under load. Wrong carabiner orientation or a non-locking ‘biner is its own disaster. We are not going to pretend a paragraph makes you safe on a cliff — learn the Swiss seat hands-on from a qualified instructor with a real safety check before you ever trust your weight to it. Use this as a refresher on what it’s for, not as your first and only teacher.
Key takeaways
- Every knot has one job. A square knot joins and finishes; it does not hold a life load. A bowline makes a fixed loop; a clove hitch anchors fast; a prusik grabs. Pick the knot for the task, not the one you happen to remember.
- Dress it, set it, inspect it. Most knot failures aren't the wrong knot — they're the right knot tied sloppy: crossed strands, no backup, short tails. Doctrine treats dressing and inspecting as part of tying, not an optional extra.
- A bowline tied backwards is a slip knot, and a water knot with short tails walks itself apart. The failure modes are specific and known. Learn them so you recognize a bad knot before you weight it.
- Every knot weakens the rope it's tied in — that's a known cost in the doctrine, which is exactly why you use the right knot, dress it clean, and don't stack unnecessary knots into a system.
- Life-safety and rappelling knots are learned hands-on, checked by someone qualified. This page is a reference and a refresher. It is not a substitute for a rope, an instructor, and a real safety check.
Sources
- TC 3-97.61, Military Mountaineering — Headquarters, Department of the Army. The rope management and knots chapter documents the joining knots (square knot, water knot), anchor knots (round turn and two half hitches, clove hitch), the figure-eight family, the prusik friction hitch, the bowline, and the rappel/Swiss seat referenced throughout this page.
- Ranger Handbook (TC 3-21.76) — Headquarters, Department of the Army. Its military mountaineering material covers the same core knots and the Swiss seat / rappel seat as a field-expedient harness.
These are public U.S. Army doctrinal publications. This page is an educational reference, not a substitute for hands-on, instructor-led training — especially for any knot that will hold a person’s weight.