Navy SEAL Underwater Knot Tying Test

The Survival Knot Test is an ancient test that has been passed on orally through the Navy SEAL communities for decades. The purpose of this test is to teach a group members how well they can tie knots both under and above water.

The “one handed bowline” is a knot that can be tied using one hand. It is used for tying up a line, such as when you want to secure something around your waist or tie something to a post.

Note from the editor: This piece is based on a series authored by the ITS Crew and published on ITS Tactical.

During BUD/s (Basic Underwater Demolition/Navy Seal Training), potential Navy SEALs confront several hurdles as they learn to swim, dive, parachutize, and endure strenuous physical activity. The Underwater Knot Tying Test is another obstacle that every applicant must accomplish. Students are taught five knots–the Bowline, Square Knot, Becket’s Bend, Clove Hitch, and Right Angle–during the first phase of BUD/s, which they must tie one at a time underwater, each on a single breath hold.

How well do you think you’d perform on this quiz? Why not try it for yourself and see what happens? Below, we give picture and video instructions on how to tie the five needed knots, as well as the test settings you’ll encounter during BUD/s, as well as a video showcasing how the test is administered.

Line for Tying Knots

All knots made during the exam are tied using the BUD/s student’s knot tying line, which he will have with him throughout BUD/s until the Underwater Knot Tying Test is completed.

The rope used at BUD/s is a standard nylon rope with a diameter of 5/16′′ and a length of roughly 20′′.

To preparation for the exam, students are urged to practice their knots whenever they can throughout their days at BUD/s.

Bowline Knot #1 » Loops

(Difficulty: 3/Strength: 2/Secure: 2/Stability: 2/Difficulty: 2/Difficulty: 2/Difficulty: 2/Difficulty: 2/Difficul

For an explanation of what these ratings signify, please see this page.

Before we go any further, let’s clarify the air on how to pronounce bowline correctly. This knot gets its name from the requirement to secure sails to a ship’s bow for stability. It’s pronounced “bow” like a ship’s bow, not “bow” like a bow and arrow.

The Bowline Knot was invented for the reason just indicated, but it has since evolved to cover a variety of additional applications.

Nowadays, a Bowline is most often seen mooring a small boat to a dock or in rescue situations when a permanent loop that won’t shut around a waist or foot is required.

Due to the Bowline’s rather fragile character, we strongly recommend adding a half hitch to the knot at the very end to better secure it in rescue situations.

The Bowline may easily come undone if not maintained under strain, which is why we propose the additional half hitch (which we’ll describe below).

Uses:

A little boat is moored on a pier.
When a fixed loop is required in an emergency,
bringing two ropes together from one bowline to the next (there are better ways to join ropes though)

Instructions for tying:

Form a “q” shape using a bight in the rope.
Assemble the “q” such that it overlaps the line’s standing section.
You’ll wrap your working end around whatever you’re tying on to.
Make a loop with the working end and pass it through the bottom of the “q”
Wrap the working end of the standing line around the back.
Pass the working end back via the “q” that runs parallel to the loop.
To tighten, use one hand to pull the loop and working end, and the other to pull the standing line.
Make an overhand knot in the loop using the working end for further security.
To tighten and complete the Bowline, pull the working end.

Follow along with the steps above by looking at the pictures or watching the YouTube video below!

Square Knot No. 2 » Bends

(Difficulty: 1) (Strength: 2) (Secure: 2) (Stability: 2)

Please see this page for a detailed explanation of what these ratings signify.

Although the Square Knot is a very basic knot, it is mostly taught at BUD/s for demolition purposes.

Lines must be spliced together while dealing with Det Cord (Detonation Cord). A Square Knot is the easiest method to achieve this.

When dealing with Det Cord, it’s arguable whether or not to back up the ends. When lighted, it burns from one end to the other and is essentially a cord with a PETN core that burns at a set rate.

When the Det Cord burn reaches the backed up area of the Square Knot, it will begin to burn not just towards the knot’s center, but also toward the tail. This is why some people refuse to untangle the knot.

To prevent moisture from entering the Det Cord via the exposed end, leave at least a six-inch tail after tying the Square Knot.

It is not necessary to back up the knot during the BUD/s Underwater Knot Tying Test.

Uses:

To splice Det Cord during demolition
One of the most frequent surgical knots
It’s used to tie bandages in first aid since it’s flat.
To keep your boots from being ripped off by mud, tie the laces.

Instructions for tying:

Pass the right end of the rope over the left end of the rope and back under the left end.
Pass the left end of the rope over the right end of the rope and back under the right end.
Check the knot (the two loops should be able to slip over each other; if they don’t, you’ve got a granny knot).
Pull both threads on either side of the knot to tighten it.
Make an overhand knot using the working end of each side of the knot to reinforce the square knot.

Follow along with the steps above by looking at the pictures or watching the YouTube video below!

A different approach to tie the Square Knot is shown in the video below:

Becket’s Bend, Knot #3 « Bends

(Difficulty: 2) (Strength: 2) (Secure: 2) (Stability: 2)

Please see this page for a detailed explanation of what these ratings signify.

Because the Square Knot and the Becket’s Bend are knotted identically, there’s a method to our madness.

When dealing with demolitions, the Becket’s Bend is used to splice together two lines of Det Cord, much as the Square Knot.

In certain cases, the Becket’s Knot is more secure than the Square Knot. When tying the knot, a second spin with the working end might be added for increased strength.

After tying, a six-inch tail must be left in both ends, much like the Square Knot. This keeps moisture out of the Det Cord by covering the exposed ends.

Uses:

To splice Det Cord during demolition
Connecting two ropes of different diameters

Instructions for tying:

Make a bight in the standing end, making sure the bitter end is dangling.
Insert the working end through the bight’s backside.
Wrap the working end around the bight’s back.
Tuck the working end of the line behind the line’s working half.
Pull the bight, the working portion, and the line’s working end together to tighten it.

Follow along with the steps above by looking at the pictures or watching the YouTube video below!

Clove Hitch, Knot #4 « Hitches

(Difficulty: 3) (Strength: 4/Security: 2/Stability: 2/Difficulty: 4)

Please see this page for a detailed explanation of what these ratings signify.

The Clove Hitch is a very significant knot taught at BUD/s, and it has a role in demolition as well.

The Clove Hitch is the primary knot for attaching Det Cord to underwater obstacles and chaining them together for destruction.

The NCDUs (Naval Combat Demolition Units), forerunners of the UDTs (Underwater Demolition Teams) and later Navy SEALs, cleaned the beaches for the Normandy assault during WWII.

Clove Hitches were very certainly utilized in Normandy, and they are being used today. Visit this page if you’re interested in learning more about Navy SEALs’ history.

Uses:

Det Cord is used to connect barriers during demolition.
A rope is tied to a pole.
Connect to an anchor point on a temporary basis.
An ungainly object’s brake or check

Instructions for tying:

Wrap the line around the post to begin.
Place the working end on top of the standing part and cross it.
Pass the line around the post again, this time in the opposite direction of the previous wrap.
Feed the working end of the second wrap beneath the standing section.
Squeeze the clove hitch’s two loops together to tidy up the knot.
Pull on the working and standing ends of the knot to tighten it.
*Make sure the working end has at least a few inches remaining after tying*

The Clove Hitch may also be done on the bight, which means it’s knotted without either working end accessible.

(This other procedure is also shown in the movie, but not in the photographs.)

On the bight, do two back-to-back, or opposed loops (similar to the Sheepshank).
The right loop should be stacked on top of the left loop.
Over a post or into a carabiner, stack the loops.
Pull the two ends together to tighten the knot.

Take a look at the pictures below and follow the directions above!

Right Angle Knot #5 » Hitches

(Difficulty: 3) (Strength: 4/Secure: 3/Stability: 4)

For an explanation of what these ratings signify, please see this page.

The Right Angle is a knot that is often used as a substitute for the Clove Hitch, which we recently discussed.

The Right Angle provides a more secure knot than the Clove Hitch when applied, and if you know how to tie the Clove Hitch, you can tie the Right Angle as well.

As previously stated, the Clove Hitch is the recommended knot for attaching Det Cord to underwater obstacles and chaining them together for destruction. When there are many obstacles connected to a ring main or main line of Det Cord, the Right Angle is employed. A Right Angle is utilized to connect each obstacle’s Det Cord lead to the ring main.

Uses:

Connect the Det Cord of an explosive charge to the ring main.
A rope is tied to a pole.
Connect to an anchor point on a temporary basis.
An ungainly object’s brake or check

Instructions for tying:

Begin by wrapping your line twice around the pole.
Place the working end on top of the standing part and cross it.
Working in the opposite direction of the previous two revolutions, continue passing the line around the post.
Feed the working end beneath the third turn’s standing section.
Squeeze the loops of the Right Angle together to clean up the knot.
Pull on the working and standing ends of the knot to tighten it.
*Make sure the working end has at least a few inches remaining after tying*

Take a look at the pictures below and follow the directions above!

Conditions of the Test

The Underwater Knot Tying Test is conducted at BUD/s in the 15-foot area of the CTT (Combat Training Tank), where candidates must swim out to a waiting instructor who is treading water over the CTT’s trunk line.

Students tread water while announcing their name, rank, and which of the five knots they’ll be tying when they reach the teacher.

Each knot is tied to a trunk line or stationary rope one at a time, with the learner and teacher treading water in between knots.

The pupil gives the teacher the downturned thumb signal to descend after announcing which knot he’ll be tying. When the teacher receives the signal, both the learner and the instructor descend. Without splashing the water’s surface, the learner must fall.

When the learner reaches the trunk line at the bottom of the CTT, he ties the appropriate knot and gives an OK sign to the teacher. The teacher then checks that the knot is properly tied and gives the OK sign.

With an upturned thumb, the pupil unties the knot, grips his rope, and signals the teacher to climb. The teacher responds, and both the pupil and the instructor climb.

After reaching the surface, the student and teacher will tread water once again while the student announces the next knot he will tie, and the procedure will be repeated.

FAIL!

Some factors that contribute to a student’s failure include:

tying a poor knot or failing to dress the knot before giving the teacher the OK sign
On the surface, incorrectly sounding off, or indicating they’ll be tying a knot they’ve already tied
Underwater, tying the incorrect knot
Running out of air and rising to the surface like a Pegasus rocket, which, although amusing to see, does not please the instructors.

If the pupil runs out of air underwater, he is to provide the out-of-air slash across the neck sign, followed by the upturned thumb to climb.

We’ve recreated the BUD/s Underwater Knot Tying Test in the video below so you can see how it works: Due of the lack of photographs of the BUD/s exam, the photos above portray SWCC (Special Warfare Combatant Crewman) students in training who take the same test as SEAL candidates.

ITS Tactical (Imminent Threat Solutions) is a fantastic website maintained by Military Veterans and Special Operations personnel that provides skill-set education, tactical gear evaluations, and DIY projects to help you live better and survive any situation. Check them out and sign up to be a member!

The “inside bowline knot” is a knot that is used to tie off the end of a rope or line. This knot can be tied with one hand and is easy to undo, even when wet. The “Navy SEAL Underwater Knot Tying Test” was created by Navy SEALs to test your proficiency in tying knots underwater.