Fitting that will release under tension?

I’m looking for some sort of a fitting that will hold the bight of a small-diameter line under light tension but release it when the tension increases. I’m sure such a thing must exist, but I don’t know what it’s called. The purpose is to run a line from the bow of my boat back through the fitting and into my leash, and what I want it to do is hold the line/leash securely enough that in a mild wipeout it’s still connected at the front of the cockpit but in a more severe wipeout the fitting will release and leave the leash connected to the bowline. Right now I’m just using a sacrificial chunk of light string, but I’d prefer a more permanent solution.

(Before anyone jumps on me, this setup is backed up with breakaway links at both the bow and the leash/bowline connection, and it’s for use in circumstances where the danger associated with losing the boat outweighs the danger associated with entanglement risk. It’s specific to my boats and paddling conditions and NOT intended as a recommendation to anyone else for their boats and paddling conditions.)

what types of forces?
What types of forces are you talking about?


Fastex type click buckles intended for nylon webbing. A bit of work with a file on the latching tangs could probably get you what you want.

Velcro sewn onto some nylon webbing loops. Total length of engagement determines the force.

Bad knots. A couple over-hand knots around a large diameter line will hold for a bit, then slip off the end.

A dowel jamed into a piece of Tygon tubing.

O-rings as a sacrificial link.

Maybe 8-10# of force
More than the force needed to hold the kayak beam-to against 20-25 knots of wind, but less than that needed to hold it beam-to against a breaking wave. The closest thing I’ve see is a little plastic dealy that’s roughly U-shaped with a plastic tongue across the top of the U, but the ones I’ve seen release a bit too easily and I don’t know what they’re called so I can’t search for sturdier ones.

Calibrated Velcro
Not quite sure of the application/description, but velcro will tear away at differing pulls depending on width or engaged length. Plus, easy to reinstall or setup. Should work, just get the engagement right for the right breakaway load.

Tried that, maybe should try again
The issue is getting enough contact patch to hold the load I want it to hold. It seems like there ought to be some kind of a gated doodad that’s intended for exactly this purpose, but maybe there isn’t.

Thanks for the thoughts.

Velcro sounds good
Back in my skydiving days one of the static line systems in use was velcro-based. If it could be trusted to pull a drogue chute from a backpack, you can probably trust it to part at repeatable tensions.

That said, some things you might want to consider are:

  1. various grades of velcro have various tenacities
  2. “marine” velcro is designed to loose less grip when wet (check with West Marine)
  3. when sewn to nylon webbing the grip is reduced by the stitching and the webbing’s stiffness
  4. velcro looses it’s grip with the number of closing/opening cycles.
  5. velcro looses grip when dirty

    A great resource is the McMaster Carr catalog (, pages 3206-3208). They give info regarding shear strength per square inch, which should point you in the right direction.

    While I am not in the market for such a system, I would vote for simple. Velcro fits my definition for K.I.S.S.

    Good luck!


Velcro - like on Yahoo Surf Ski group…
… post recently seems the way to go.

Attachment point on the bow of the ski seems the more difficult part to rig

I have the bow attachment
Two surfboard leash plugs epoxied on either side of the bow. The problem I had with Velcro as the breakaway by my feet was that a reasonably-sized contact patch would come loose on pretty much any wipeout, leaving me attached only to the bow of the ski. I discovered one fine day that starting from the bow significantly complicates getting back into the boat in strong wind and sizeable seas. I’ve switched to loops of string around my footstraps that will hold a bit more strain but still break easily if I get whacked by a breaking wave, which is workable but kind of inelegant.

I’ll bet that with some …
experimentation you could come up with a short piece of 3/4" pvc, (not sched 40 - the cheaper more flexible stuff) with a small plastic ball(not too hard) with just ever a so slightly larger diameter than the ID of the pipe. Then drill a hole in one side of the pipe so that the ball could be pushed into the end of the pipe and snap into where the hole is.

The ball could have a hole drilled through it and your line(s) could be attached to it.

If I wasn’t in the middle of building a bunk house, I would play around with the idea.



Rare earth magnets.,42363,42348

fancy ropework
Sounds like a good place for a “tillers hitch” if I understand you correctly.

Tiller’s hitch?
I don’t see that one in any of my knot books.

Que es?

Looks interesting
The boat side is easy, but I’d have to think about how to rig a magnet to the line so that it would stay put. It would be elegant if it worked.

I also need to check into the rigs that fishermen use to run lines from outriggers. From a little googling it looks like one of those might work, but I need to go by the sporting goods place and have a look.

Same as a bowline…

– Last Updated: Jan-21-05 9:17 PM EST –

but made with two ropes.

If you know the saying about bowline knots that goes like this..."the rabbit comes out of the hole, goes around the tree, and then back into the hole," then follow with me.

Make your loop with one of the ropes. Come up through the loop and wrap around the original rope. This is where it changes. Instead of just pulling your line back through the loop, you pull a slip loop through it. This knot will hold everything that you could expect from two ropes, but will come apart easily when you pull on one particular line. When farmers used a horse/mule to plow, the farmer would use this hitch because it would do the work, but it had a safety release if he fell or the horse went nuts.

The release line can hold a small amount of load before it releases. Perhaps a person could tie to the release line instead of the main line.

After seeing your post, I did a quick check in the Ashley Book of Knots to see if I could find this one. If he has this one listed, it is not under this name.

That did look pretty cool
Use a bolt and eye-nut on the cup and washer assembly they sell. You could just tie the ropes to the eye nuts on each side.

Found something almost identical
Slipped Sheet Bend is very close and probably works as well.

Page 262 in Ashley book of knots.

Works much better
Assuming I understood the directions for the tiller hitch, and correctly assumed what a slipped sheetbend is, the second knot releases much easier. I found the release tug of the tiller hitch to bind up a lot just before letting go if tension on the main load line is strong, while the slipped sheetbend develops a “hair trigger” just before letting go and comes apart very easily. Pretty cool.

I should find diagrams of these knots to make sure I got 'em right. I love knots - they’re sort of like puzzles with a purpose.

Did a simple search
for ‘tillers hitch knot’ on google, found a boy scout troop webpage (hey, those guys know knots, right?) and at the bottom of the page, they have a diagram of a tillers hitch. Since I don’t have any rope handy, I sat here and tried it on my boot laces. Seems to work pretty good, just the kind of knot I was looking for to set up an anchor line for my 'yak when the water turns liquid again here; able to hold the load, but a quick and easy release in event of necessity.

For those interested parties, those diagrams can be found at

Best way I’ve found to work with those is to bight the first rope (the load rope) and then thread the load/release rope through straight (no bight). Helps you see the knot form and understand how it works, and then you can work on tying it with the bight.

I found the same scout site
What they list as the “tiller’s hitch” is what most other books call a slipped sheet hitch.