Below are listed 3 recent threads which discuss most aspects of the construction and use of a short board leash in surf kiting. There are many members of KF who see a need for the use of a board leash in certain situations. In the past 6 years, I have paid attention to the comments of the members interested in this subject, and have arrived at a design for such a leash. I have discussed the components of this design in the threads listed below, and have included a picture of the leash, that I have been testing in both small surf and flat water.
The one thing that I like about your design, is the fact that the row of "Zip-ties", located at the harness, allows the rider to easily hook his leash back up, after an incident, where the board was torn away from the rider. In order to hook the leash back to the harness, with my design, the rider needs to do some prior training to develop the skill to hook the "automatic mushroom push away release", using only ONE hand. The requirement of "reassembly by the use of only one hand" is a very important component in the design of any board leash. Also, the fact that your "Zip-ties" are located at the riders hip is a very good design, in that it allows the rider to grab the floating leash and not the board, in order to do the reassembly of the leash.
As far as the question about what size "Zip-tie" to use, for the proper amount of release-force... I have experimented with this, and have concluded that a good compromise force is around 100 pounds. "Zip-ties" are rated in pounds of force... 10...20...30...etc. So, the use of 2 "Zip-ties" each rated for 50 pounds of force, will achieve this goal. In order to achieve this amount of release force for my surf leash design, I have created a "fuse" that automatically and consistently releases the leash at about 90 pounds of pressure. I have discussed the construction of this "fuse" in one or more of these threads, but if anyone is interested in more detail, just say so, and I will expand on the construction detail.
One suggestion, which would improve on your design, would be to incorporate 2 quick releases (one at each end of the leash), so that when you get rolled in the surf, and the leash wraps around your body (which it will do often), then, you can release either end of the leash...letting just the board go loose, or letting the whole leash and board go loose. You can see these 2 releases in the picture. I have tested the leash in both surf and flat water, and have been glad to have had both of those releases, along with the automatic force calibrated release.
Having a very thick leash, that the rider can feel as it wraps around the riders body is an important component, and your leash has this characteristic.
One other improvement to both your leash and my leash would be a large yellow float, located at the harness end of the leash, which would guarantee that the loose end of the leash would float, and be visible in the surf, allowing the rider to more quickly and easily locate and grab the end of the leash, prior to reattaching it to his harness.
Anyway, keep up the good work, and maybe we will arrive at a fairly safe, reliable, and practical leash design, even though leash-less will probably always be the safest way to ride.
Board Leash Attack:
Board Leash In Light Wind:
Surf Leash Length: