The Prusik Knot

And Its Kiting Applications

The Prusik knot. Where would kite-fliers be without this great shiftable, lockable knot... A bit of a pain to tie at first, but it makes adjusting a bridle so easy! Pulling the bridle straight unlocks the knot, letting you shift it along the bridle line. Pulling on the lines as pairs as in the last photo causes the knot to fold, locking it in place.

Knot Tying Illustration - The Prusik Knot.
The Prusik Knot - 3
The Prusik Knot - 5
Knot Tying Illustration - The Prusik Knot - 7
Knot Tying Illustration - The Prusik Knot - 2
The Prusik Knot - 4
Knot Tying Illustration - The Prusik Knot - 6

I use the Prusik on horizontal bridle loops to shift the knot left or right across the kite, for trimming purposes. More commonly, it's also used to slide up and down the bridle line of, say, a Diamond kite to adjust the Towing Point fore and aft.

On kites with 4 legged bridles, arranged as an upper and lower loop plus a connecting line, this means 3 shiftable knots. For example, the Dowel Rokkaku and Dopero. At least you only have to tie these knots once.

Although it seemed a little excessive at the time, I took this approach on even my smallest Dopero. A tiny kite with a 30cm (12") wingspan. But it sure paid off, since some fiddling was required to get a decent flight out of it!

More recently, I have also used this knot on the vertical bridle loops of a large Genki. Same deal, tiny adjustments can trim the kite left or right.

Now, if you really want to go overboard with knot-tying...

The book Knots: The Complete Visual Guide has an amazing average review score of 5 stars from 12 reviewers - the last time I looked. If it's a more general knot-tying resource you need, this would definitely be it!

There are other ways, some possibly a little simpler, to obtain a shiftable knot. However, the Prusik has worked so well for me over the years that it's the one I would recommend.

This mountaineering knot was invented in 1931 by Dr. Karl Prusik. With one 's'. At least this web-master has finally got it right. Many others still haven't! Prusik later authored a mountaineering manual, which was the first publication to feature this well-known sliding knot.

Tying a Prusik knot actually becomes fun after a while, funnily enough! Be sure to put a Simple knot into the short end of the line though, since constant use tends to pull line through the knot. The short end gets noticeably shorter than you remember tying it originally. Perhaps this happens during locking and unlocking...

E-book special of the month (25% off)...

Click to get 'Making The MBK Parachute Kite'

This printable e-book takes you step-by-step through making a 119 cm (4 ft) wide Parachute kite. It's not quite that wide in the air since the canopy takes on a distinct curved shape when inflated. This 14-cell kite performs best in moderate to fresh wind speeds. That's 20 to 38 kph or 13 to 24 mph. In gentle winds, this kite will hang in the air at fairly low line angles. In fresh winds, it pulls firmly for it's size, so small kids should only fly it while supervised!

Every kite design in the MBK Soft Series satisfies the following points...

  • Materials are plastic sheet, tape and line – and nothing more!
  • Tools are a ruler, scissors and a marker pen - and nothing more!
  • All cuts are along straight lines.

For the greatest chance of success, I make recommendations regarding the materials. For example, the type/weight of plastic, type/width of tape and line type/strength. Close enough should nearly always be good enough, since the design is well-tested and should be tolerant of small differences from my original.

Get the e-book for making the MBK Parachute kite. After making your first one in plastic and seeing how it performs, you can try soft Tyvek or rip-stop nylon for your next build.

The e-book is a PDF file - which means printable instructions to refer to while you make the kite. It also means convenient off-line access if that suits you better.

What's New!

  1. The Classic Cody Kite

    Aug 23, 17 06:00 AM

    This previously published page gives a quick insight into the structure and materials of the original 'War Kites' by Samuel Cody. Plus some history and photos of course. Intriguing stuff...

    Read More


Plenty of fun kite info, photos and videos - there's definitely too much here for only one visit! Feel free to leave your impressions of this site or just this page, below...

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Wind Speeds

Light air
1-5 km/h
1-3 mph
1-3 knots
Beaufort 1

Light breeze
6–11 km/h
4–7 mph
4–6 knots
Beaufort 2    

Gentle breeze
12–19 km/h
8–12 mph
7–10 knots
Beaufort 3    

Moderate breeze
20–28 km/h
13–18 mph
11–16 knots
Beaufort 4    

Fresh breeze
29–38 km/h
19–24 mph
17–21 knots
Beaufort 5    

Strong breeze
39–49 km/h
25–31 mph
22–27 knots
Beaufort 6

High Wind
50-61 km/h
32-38 mph
28-33 knots
Beaufort 7