different types of knots and their uses pdfdifferent types of knots and their uses pdf

different types of knots and their uses pdf different types of knots and their uses pdf

Or, to find a knot for a specific purpose such as to make a loop or tie a rope to an object, go to the Rope Knot heading above and pick the . However, in the case of a moored vessel, this is not very common. Feed the bight of cord through the inside of the sling. Prusik Knot. Pass the loop up behind the crossing strands on your palm. Capstan Nut This type of nut is round in shape and has small holes in its circumference. These days, the Carrick bend isnt as popular as it probably should be, but thats mostly because its more difficult to tie correctly than some of the other options on our list. It can also be used in load-bearing situations, such as in climbing and mountaineering, but with caution. !XC4ftZvRKF@YyKN$4i#I#Nos8P s5Jp/(7-vB5W;0 +JjQpV4 /?>0>j$.`S]u]h,v 4bkhuW:Wj?5RlW$ zY0&VVBZc4=EJI;/^x.q00!lz$>HMY8qqA.3HtCb\Yl$.e]`qy/sW\p[y\::s6]"fT,il{Sq4tL52jp.'1Nl6'tV-g(#4HAl+jBnJ=9`NM ;Q^T o}HOP_|F{ppyPG Y*cq ;Y/6c&[ u endstream endobj 3 0 obj 718 endobj 4 0 obj << /Type /Page /Parent 170 0 R /Resources << /Font << /F0 180 0 R /F1 182 0 R /F2 183 0 R >> /XObject << /im1 11 0 R >> /ProcSet 187 0 R >> /Contents 5 0 R /MediaBox [ 0 0 596 842 ] /CropBox [ 0 0 596 842 ] /Rotate 0 >> endobj 5 0 obj [ 7 0 R 9 0 R ] endobj 6 0 obj 1083 endobj 7 0 obj << /Length 6 0 R /Filter /FlateDecode >> stream Also, if you tie a clove around something too big, it can slip off. You can constrict it by tying a constrictor knot around the rope with a bit of twine, or you can tape it. Here are the different categories of nautical knots and what they're used for: Loop: This type of knot is used to create a strong loop that allows the rope to be attached to a fixed point (sail fasteners or mooring cleat). @v `> W/%Y?c)Wol. Its also useful for camping if you need to tighten guylines on tents and tarps. To create the girth hitch with a sling around another rope: Use: Creating a secure bight of rope. One of the most common knots in the world, the heel box is the knot that most of us actually use when tying our shoes. follow with the second Half Hitch., but in completing it, make a round. Additionally, the double overhand stopper knot tightens on itself. An anchor bend is used by attaching a knot to a ring. Not only does it teach discipline and focus, but the skill also comes in handy for survival in critical situations. Hold a bight of the sling cord in one hand. Place the working end of Rope B underneath the loop you created in step 2. Its best to practice this with a small amount of weight pulling on the opposite end of the line, like you would experience while pitching a tent. Different types of knots: tight interlacing of two ropes.A knot is also a unit of speed in aviation and marine navigation equal to one nautical mile per hour. It has also traditionally been used to make cargo nets. The Bowline is also one of the four basic maritime knots, the other three are the Figure-Eight Knot, the Reef Knot and the Clove Hitch. Then tie the left thigh to the left upper arm bicep. Cross the working end of the rope around the standing end once to form a loop. 0000002674 00000 n It is particularly beneficial if you need to load these two ropes but if you want to avoid the jamming that inevitably happens with the double fishermans. Thread the working end of the rope through the carabiner. A BEND is used to fasten two lines together or to fasten a line to a ring or loop. Choose a knot by name from the list. In the knotty would, capsizing means that the knot has rearranged itself into a different knot. If you choose to tie a sheet bend, keep in mind that you may need to use the double sheet bend if there is a very large size difference between your two ropes. In many ways, the Kleimheist is similar to the Prusik knot. It is formed by : First passing the end of the rope around the post twice. Dome Nut This type of nut is dome shaped and it's also protected from water, dust, etc. Named after German doctor Karl Prusik, who first promoted its use in the 1930s, the Prusik hitch is a popular friction hitch among climbers. If you want to tie a truckers hitch, youll need a line and an object to anchor it to. In many cases the economy is not that important. Annoyed by the lack of quality online outdoors publications willing to uphold high standards of value and ethics, he decided to make the resource he would have wished to read. However, keep in mind that there are much better closures, including double closures, if you dont use tape. bad maiden will be punished.bloomfield school district jobs May 31, 2022 different types of knots and their uses pdf Low profile construction infrequently gets stuck. Use: Creating two loops in a rope. Most people find that the figure eight on a bight is easier to untie than the overhand on a bight after being loaded. Use: Creating a secure stopper knot in the end of a rope or line. Wrap the loop created in step 1 around the back of the standing end of the rope in the opposite direction of the anticipated load. This loop can then be used to tie into if youre climbing or to isolate a damaged section of the rope. justise winslow hip replacement surgery; what stores take venmo scan. Please note: If you are new to knot tying, please review the knots in the Brownie One final thing before we dive into our list of 25 types of knots: There are a few pieces of terminology that you need to know to make the most of this guide. Place your dowel (or ring) on top of the folded cord just above the loop. However, with proper knot-tying technique, there is nothing inherently dangerous about this knot. They are also easy to untie, even after theyve been loaded. They illustrate the fundamental principles of knot tying. Use two half hitches to tie a rope to a tree, ring or dock. It will allow you to adapt quickly, and use the best knot for your current . Once the seam is sewn and pressed open, zig stitch the raw edge and and trim away . However, the ease with which this package can be removed is one of its main drawbacks. %PDF-1.2 % Use: Tying two ends of a rope or line together in a non-load-bearing situation. While it is also effective when used with cord, the Kleimheist is second to none when making a webbing-based friction hitch. If you don't keep it under load then it may work itself loose. Clove Hitch. Take note of the overall shape of each knot. Pass the tail of Rope B in front of its standing end. Describe the knot types and their usage in the fire service. While this knot can be used for many purposes, its primary purpose is to create a loop in the middle of a length of rope. 0 . One of the less commonly used bends on our list, the zeppelin bend is a solid choice if you need to join two ropes together. In fact, we use a variation of the square knot, which is also called the reef knot, for many things in the outdoors, including for reefing a sail on a sailboat (hence the name). However, like the double fishermans, the zeppelin also requires very long tails (think at least 8 inches/20 cm). The strand in your left hand is Rope B. Do not use when safety is essential. Their story is a long one and shockingly global; many societies have developed motifs of endless or infinite knots. 0000004062 00000 n Create a figure eight on a bight or a directional figure eight in your line, about 2 feet (60 cm) from your anchor point. TOAKS vs. If the clove string is tied around something too smooth (think a metal post), it can slip and the bond will fall off. It can be used for ropes of different diameters, but this is not recommended. Also, there are five terms you should know: With these important knot terms out of the way, lets turn our attention to the 25 types of knots you need to know: Use: The two ends of a rope or rope are tied in a non-heavy position. There are thousands of different types of knots out there, many of which are infrequently used. Wrap the sling around the rope at least 3 times moving. Make a second Half Hitch and then wrap over the entire knot to finish with a final Half Hitch to the other side from your starting place. Bear Adventure - Bear Necessities 5: Demonstrate how to tie two half hitches and explain what the hitch is used for. The Carrick bends advantage over other bends is that it can be easily untied after being subjected to heavy loads. In many ways, the Orvis knot is similar to the Palomar knot, but the Orvis knot is popular because its relatively easy to tie. The tails of each rope should lie in opposite directions. However, few know the history and meanings behind these beautiful designs. Although it can also be used to join ropes of equal size, it is unparalleled in its ability to effectively join two different-sized ropes. Place the bight of Rope B over the bight of Rope A. Do note that this knot cant be tied if either or both ropes are under tension. The one major drawback to the double overhand stopper knot is that it is very, very difficult to untie after its been heavily loaded. Not to be used whenever safety is important. Pass the working end of Rope B over the standing end of Rope A and under the tail of Rope A. Thread the working end of Rope B through the loop in Rope A that you created in step 2. Popularly used for rappelling off of two ropes. Tie a double overhand in the working end of the rope. Eddie Bauer vs North Face: Which Brand Is Right For You? Pull down on the sling in the direction of the expected load (in this case, downward) to create the Kleimheist. different types of knots and their uses pdfproforce senior vs safechoice senior. montclair high school california famous alumni. The primary advantage of the bowline is that it is very easy to untie after its been loaded. If you want to practice tying the tensionless hitch, you need a rope, a carabiner, and an object to tie the hitch around, like a tree or post. Thread the working end of the rope through the loop. The main disadvantage of the double button on the handle is that it is very difficult to remove it after a heavy load. Square Knot. Although there are a number of other knots out there that are easier to tie and that can do many of the jobs of the alpine butterfly, they are simply not as good in most situations. Knots For Joining Two Ropes Together. A toggle knot is preferred because of its size and reliability. However, the ease with which this knot can be untied is also one of its key drawbacks. First of all, the rope should be attached before the bracelet. Thread the working end of the rope twice through the loop you created in Step 3. Cross Rope A over Rope B. Rope A should now be in your left hand. The tail of Rope A should face up and to the right while the tail of Rope B should face down and to the left. I^pWCv]KRkX{`0"!LDz$auX>,RoPug`_N511fY" HUn0@vHjvhNE.MGeQI-Vj0L,o,\g 8HV! Make an underhand loop by taking the running end of the rope and passing it under the standing end. You might have unknowingly formed this knot many times. Cultural . If you are reading this article to learn which knot to use in non-life situations or because you consider yourself a master at tying knots, then take the knot as you wish. Create a bight in the thicker of your two ropes. Also, please note that there is a similar, but very different knot called the flat figure eight that should never be used for load-bearing situations. The biggest advantage to the clove hitch is that it is easy to untie, even after being loaded. If you expect strain to come from more than one direction, an alpine butterfly knot is generally best. Another fantastic stopper knot, the aptly-named figure eight knot is a fan-favorite among climbers everywhere. 176 0 obj << /Linearized 1 /O 178 /H [ 688 384 ] /L 252004 /E 6593 /N 28 /T 248365 >> endobj xref 176 14 0000000016 00000 n A knot is not a knot if it cannot exist on its own. You can make this type of knot through two successive hitches half tied to an object. In a general sense, it includes the words bends and hitches. Not to be used whenever safety is important. 8 Basic Knots and Their Uses. Steps to tie the Line-to-Hook/Lure Uni knot: 1. Otherwise, you may not get enough friction on the tensionless hitch to support a given load. With those key knot-tying terms out of the way, let's turn our attention to the 25 types of knots that you need to know: 1. This knot can be used to latch onto another object, and can be adjusted to be tightened or loosened as preferred. Relatively easy to inspect for proper technique. Hold two ends of rope or webbingone in each hand. There are many different types of . These knots are especially good for nylon monofilament, Fun fact: most shoelaces are tied using a variation of the square knot. Related: Learn how to hem jeans by hand or machine. Decorative wall hanging can have rye knots added throughout the weave as well. Use the bight to create a figure eight shape, just like you would do with a regular figure eight knot. Pull it tight. Make a constriction around the rope about 7.5 cm from the end. The Four In Hand is one of the oldest knots, thought to be an invention of British horsemen. Thats because it offered a straightforward way to belay and rappel before the advent of modern belay devices. Create a loop with the working end of the rope. Very popular in rock climbing and sailing. "W(P6br'r{nt^C;CT0Pro01o4WmY4z2I{[Mqi4yM1%|/G?`< 1f4};>vZ73,dwV(r=, g+ii%. Its actually one of the most reliable stopper knots out there because it has substantially more bulk than its relative, the overhand knot. Pass the working end of the rope through the loop you created in step 2. While we used these words interchangeably in some of our directions for simplicitys sake, its worth knowing the difference between these terms before you embark on your knot-tying career. Many are also components of other knots or they provide the underlying structure. 5 Different Types of Maps General Kinds, History of Mapmaking & Parts of a Map (Photos, Infographic and Facts). Reef knot: interlacing of ropes made of two half-knots inverse to each other. Therefore, in load-bearing situations, the bowline should always be tied with a stopper knot (preferably a double overhand) on its tail. By: Scott Way If you're a boater knowing how to tie a few knots isn't just handy, it's a valuable life skill. Use: Joining two ropes of unequal size. There are several types of knots. Ensure that the tail is. There should be a sizable diameter difference between these two lines, with the cord being at least 3 mm thinner than the other rope. The Different Types Of Knots For Different Tasks. Use: Making a tight knot at the end of a rope or rope. Grasp a section of the rope and twist it into a loop. Requires more rope to tie than the overhand, Can flip over itself and fail when used as a stopper knot. Simple way to secure two ropes for load-bearing situations, Popular option for creating Prusik Loops for climbing, Tails must be left very long to prevent failure, Additional precautions needed for slippery rope fibers (Dyneema, etc. The girth hitch is one of the easiest knots to tie and it is used in nearly all aspects of our lives, such as for attaching the strings of zipper pulls to the zipper itself. The clove hitch is a simple but important survival knot that's easy to tie. It can be dangerous if you use the wrong knot for something. Pull on all strands to tighten and form the zeppelin bend. Tighten the working and standing ends of the rope to create the figure eight knot. In particular, there are five phrases that you need to know: With those key knot-tying terms out of the way, lets turn our attention to the 25 types of knots that you need to know: Use: Tying two ends of a rope or line together in a non-load-bearing situation. Use: Joining two pieces of webbing or rope together. Sharks In Lake Michigan: True Story or Urban Myth? Grasp the working end of the rope in your right hand. Unravel the end of the rope all the way to the constriction. Essential skill for forming dozens of other knots, Can be difficult to untie after being loaded, Hold the working end of a rope in one hand. Yucatan knot; J knot; Drop shot rig; Fishing Knots for Connecting the Parts of Your Fishing Gear. Remember that almost every puzzle can be recorded in different ways. Fold one half of the right loop over itself and to the left. Two Half Hitches. Can also be used with cord. Strong and reliable bend for two ropes Secure and reliable bend for two ropes Securing a rope to a taut line Securing 2 ropes with a loop at each end For securing lines of large diameters . Maintains much of a lines breaking strength. Useful, though less common, in many other outdoor pursuits. Our content is reader-supported. Its not necessarily obvious by looking at a photo of it, but the double fishermans is effectively two double overhand knots stacked on top of each other. 3. Then go around the standing end and up through the loop. It is one of the most reliable knots because it is much larger than its counterpart, the folding knot. However, we cannot teach you about all recording methods in this article. Describe the types of knots to use for given tools, ropes, or situations. Carl is the founder and strategist of Outforia. This is the primary characteristic of most Celtic knotsthere is no . Pull the standing ends of each rope to create the double fishermans knot. We will also describe our chosen method as if you were tying the knot with your right hand. After it was first developed in the 1950s, the Munter hitch became a popular choice among climbers. Cross the working end of the rope around the standing end to create a loop. 4. Wrap the working end of the rope behind the standing and of the rope. Additionally, if you tie a clove hitch around a very large object, it can also slip. Grab the top of the two loops that you created around your left hand. Tuck the lower left loop through the upper left loop. Also, remember that while you can tie a figure eight to the ribbon, its not ideal. Pull on the standing end of the rope to tighten and create the round turn and two half hitches. Pull on the working end of the rope to tighten the Orvis knot. Use: Joining two ropes of similar sizes together. It's amazingly simple. Celtic knots are strongly associated with the Irish culture in Ireland and overseas. The knots in this guide can be used in a wide range of different activities, so theres sure to be something in this article that will be useful in your life. When tied properly and with a large amount of tail on either end (think 2 feet/60 cm or more), the clove hitch is one of the most versatile tools in your knot-tying toolbox. Secure the pulley to a stationary object (like a pole or branch) with a quick-release half-hitch or, for extra security, two or more standard half-hitches. It can also be used to apply friction to a rope system, such as for creating a one-way pulley. Bind the ends of the strands with tape to keep them from unraveling. Two half hitches knot is one of the recommended knots of Idaho State University. The main advantage of the square knot is that it is easy to tie and untie. Greatly reduces the breaking strength of rope, Requires equal tension to be applied to both rope strands. The knots in this tutorial can be used in a variety of ways, so there is something in this article that will be useful in your life. Thread the other end of the sling through the bight you created in step 1. The truckers hitch is a commonly-used hitch for tensioning lines in a wide variety of situations. However, this is not possible with carabiners when the hook is properly attached. If you climb, consider hiring a guide or instructor to show you the ropes. As its name suggests, it has long been used by truckers to secure loads and tarpaulins. Half Hitch. HVn0k{i, One of the best knots for joining two lines of similar size. Knot Types And Their Uses theory of knots quickly leads to deep results in topology and geometry. If youre working with ribbon, consider an overhand knot instead. The round turn and two half hitches consists of two parts: the round turn, and two half hitches. Step 3: Reverse directions, and go across the top of the cleat going the other way. It can be tied in a number of different ways, depending on personal preference and the situation at hand. Tie a single overhand knot using both ropes. There are 7 knots ever firefighter must master early in their career. The Windsor is almost a perfect triangle. Note that this knot requires a large amount of tail (1 ft/30 cm is a good minimum). The sheet bend can handle fairly heavy loads; however, care should be taken to provide very long tails if the sheet bend is going to be used in load-bearing situations. The flat figure eight is tied just like the flat overhand but with an additional loop to create a figure eight shape. The choice of knot is based on many years of sailing combined with the opinions and advice of many assistant captains. Like the Prusik, the Kleimheist is a friction hitch, which means that it can provide friction on a rope for rope ascension and for the creation of one-way pulleys. Thread the working end of the rope through the bight you created in step 1. Square Knot. Plus, the alpine butterfly can be subjected to heavy loadsall without rolling over and failing. But theres a technical difference between these three techniques. The simplest knot, the overhand knot is another knot youve tied many times in your life even if you dont know its name. Thread the working end of the rope through the loop you created in step 2. This means that you can only load a Kleimheist from one direction. luis garcia astros contract. With these important knot terms out of the way, let's turn our attention to the 25 types of knots you need to know: Use: The two ends of a rope or rope are tied in a non-heavy position. Create a small loop in the working end of the rope, approximately 1 ft (30 cm) from the end of the rope. Knot tying is a time-honored pursuit that takes hours of practice to truly master. The Four-in-Hand is much more narrow. The knots used should hold well under water and not come undone under tension. Step 1: Wrap the line around one side of the base of a cleat, under the "horns" (the ends on either side). Pull the working and standing ends of the rope to create the double overhand stopper knot. Anchor bends, also known as Fisherman's Hitch and sheet bends, are also essential knots. The Bowline is a common rescue knot used when securing and lifting people or equipment. Commonly used in climbing, hammock set-ups, and other similar situations. One of the benefits of learning the overhand knot early in your knot tying career is that the overhand is the basis for a slew of other knots. 1. Wrap the working end of the rope around your anchor point. But note that the girth hitch substantially reduces the breaking strength of rope. Halyard knot: interlacing of ropes used to attach the halyard to a sail. The Prince Albert has a second fold that peeks out at the bottom. Knot - An intertwined loop of rope, used to fasten two such ropes to one another or to another object. The Lark's Head Knot is a popular knot for attaching your macram cords to a dowel or ring. However, the truckers hitch is somewhat less easy to adjust than the less common rolling hitch. Considerations: To tie make a loop on the standing side, slide the end of the rope through the loop like if making an overhand knot. It's for a quick temporary use, not long-term. Use: Creating a loop in the middle of a length of rope. A knot, even when not in use, will hold its shape or form. Take working cord 1 and take it to the right, under the filler cords and over working cord 4. You will need rope and an object, like a post, to practice tying this knot. This knot is ideal for use in thin fishing lines that need to be attached to a fish hook. These knots need to be made by hand and can be quite tedious. Therefore, learning this knot will prepare you well for your future tying endeavors. Also called the ring bend, the water knot (actually a bend) is one of the knots in the overhand series. If you want to keep things simple, you can use the word knot as an umbrella word for all of these terms. Can fail when loaded in the wrong direction. 1. Pull the working end of the rope back toward the anchor point until you achieve the appropriate tension. Clip the loop from Step 3 into the carabiner to create a Munter hitch. Pass the working end through the second loop that was created in step 3. Use: Attaches rope or rope to a post, carabiner, tree or other object. It is important to learn different types of knots and what the purpose is for that knot. 4. Wrap the working end of the thinner rope around the backside of the standing end of the thicker rope. Prusik Knot. Also, keep in mind that, while you can tie the figure eight in webbing, doing so isnt ideal. Wind the rope head back to where it came from, and pass through the gap formed in Step 7. The main advantage of the tensionless hitch is that it is very easy to untie after being loaded. An essential skill for any knot tying enthusiast, the half hitch is an ancient hitch that forms the basis of a wide range of other hitches, knots, and bends. This should create a butterfly-like shape in the rope with two upper and two lower loops. Line Parts. The Square Knot (Reef Knot) and Sheet Bend are the two basic methods of joining two ropes; and the Figure 8 . A bow knot is more of a decorative basic knot because of its large loops. 0000005416 00000 n So long as you provide it with enough tail (at least 10 in/25 cm; more is better), its unlikely to come undone while under load. Pull on the standing end of the rope to tighten and create the half hitch. Loop the line under the end of the cleat. This is considered one of the most essential knots and commonly called a double hitch. If you want to use webbing, the overhand knot is best. It has long been used for nautical purposes, hence the name bowline, which is an amalgamation of the words bow (meaning the fore of a vessel) and line (referring to the rope itself). Preferable to the overhand knot due to its added bulk and reliability. Pass the end of the rope through the standing end to create the first half hitch. Use: Attaching rope or line to a post, carabiner, tree, or any other object. This is the easiest and most basic of all macrame knots. Describe hoisting methods for tools and equipment. Insert the working end into the same loop again. For securing a line to a cleat For wrapping a line . Pull the tails and standing ends of both ropes to tighten and form the Carrick bend. Pass the bight of the sling around the back of the rope. Hb```f``d\g`@ r@24 ;NPWTX@KEX12NyE@/3+O,/2*v*MV)d65(,|D,&,"LNTAMrknj```PJk````Hk`6R@>JP$B84[ Knot strength is often expressed in percent, such as the percentage of the strength of the line at which the knot (weaker than the line) will break. Lay on one side, and "Tie wrists together with a basic wrist tie. Often used in climbing. Zigzag. The strand in your left hand is Rope B. Practical Uses of a Square knot. Many of the knots that we discuss in this guide can be used for a wide range of different purposes, from tensioning a tarp at your campsite to tying up your sailboat at the dock.In many cases, a knot isnt a serious risk management concern. 2. Its also easy to untie after being loaded. Rope Knots Sketch Set With Different Hitches And Bends On White Background Isolated Vector Illustration Stock Vector . In fact, there are only two sides of the figure eight. Transportation costs. This makes it ideal for use on guylines in windy conditions. 0000001565 00000 n The main difference between a Kleimheist and a prusik is that a Kleimheist is unidirectional. ), Take the working end of Rope A and create a double overhand knot, Take the working end of Rope B and create a double overhand knot. Its a knot that many of us learn to tie as children, even if we dont know its proper name. For example, the knot you use to tie-in to the rope while rock climbing is whats responsible for protecting you in a fall.If youre reading this article to learn knots that youll use in non-life-or-death situations or just because you fancy yourself a knot-tying master, then feel free to get knotty as much as youd like.But, if youre here to learn how to tie knots for rock climbing or any other situation where your knot is an important safety tool, then please be cautious with your new skills. *q\B~_-X%` `, d~.HB At the same time, because this knot tightens on itself, it cant be untied while under load. 1. Cord thats anywhere from 5 to 9 mm (0.19 to 0.35 in) thickness is usually best for practicing your knot tying skills, but anything you have available is better than nothing. Traditionally used for ascending a rope. used kompact kamp mini mate for sale. It is a temporary knot unless the eyes are fastened to the standing part of the rope on both ends. Fold one macram cord in half creating a loop. Attach the carabiner to the standing end of the rope. The figure eight is designed to be self-tying, so it cannot be untied when tied with too much tail. Take the last cord (working cord 4) and move it to the left, over the filler cords (cords 2 and 3) and under the first cord (working cord 1). The only major downside to the round turn and two half hitches is that it can work itself loose if it is not under tension. Pull down on the loop and on each of the other strands of rope to tighten and create the directional figure eight. When tying the Carrick bend, note that the tails of each rope must be diagonal from one another. If you load the Kleimheist from the wrong direction, it will not provide the same level of friction. Knot - a knot is tied in a rope or piece of webbing. One big advantage of the Prusik over other friction hitches is that it can be loaded from the top or bottom.

Angela Morrison Clinton Morrison Wife, Iowa Farmer Dead After Tractor Accident, Mesa Airline Flight Attendant Uniform, How Much Did Keanu Reeves Make For Cyberpunk, Alcoholic Chicken Seinfeld, Articles D

No Comments

different types of knots and their uses pdf

Post A Comment