dazarter wrote:Ever heard of a roll leash? works about 100 times better than a normal surf leash, board never can spring back at you - ever, and after a spill the board just comes slowly back to you….….
I hope the “roll leash” that is referred to, is not some variation on the old Oceanic Reel Leash shown in the attached picture. If it is one of these, then please read this lengthy analysis of the physics and the scenario, which is likely to take place a split second after this picture was taken:
"I wonder if all of the injuries (in the gory pictures) resulted from some “variation of the theme”, happening in the few seconds after this picture was taken. The “theme”, which may be the common element of most board injuries, would be that of the “loading up” of the leash, due to the resistance of the board, causing the leash to stretch, and thereby gain “potential energy”…which then turns into the “kinetic energy” force, responsible for propelling the board toward the kiter?
I haven’t tested the conventional surfboard leash, but have tested the ½ inch single thickness, nylon webbing strap that comes with the Oceanic Reel leash for its ability to store up this “potential energy”…and the results were scary…I would like to know how the plastic tubing of the conventional surfboard leash compares to the ½ inch webbing.
Here are some facts:
(1) When I applied 85 pounds of force (with my weight machine) to a 44 inch length of the ½ inch webbing, the webbing stretched about 4 inches (11% of its length). When the webbing was under tension and I applied about 100 pounds more of force to the suspended weights, it made the 85 pounds of weights on the machine…bounce up and down about an inch.
(2) This ½ webbing has a rated strength of 1000 pounds. Like most strength ratings, this is probably an under-rating of the true strength.
(3) The webbing is about 4 times as long as my test sample, so I think that it is reasonable to assume that the full length of the webbing can be loaded up with at least 4 times 85 pounds of force or 260 pounds of force…and I would guess that the full potential load and resulting force of the leash would be 3 times that amount of force.
(4) Without doing the math to determine the momentum with which an 8 pound kiteboard has the potential to slam into the kiter’s body, I would conclude from the damage seen in those pictures that it is something to be feared and respected.
(5) The fact that many kiters have actually broken the webbing on the reel leash indicates that the situation actually occurs, whereby the webbing is loaded up with more than 1000 pounds of force. The expected deterioration with time may allow the leash to break at less that this force, so this should be considered also.
(6) When these leashes break, most often the conclusion of the kiter, and the resultant complaint from kiter is: “the problem with the leash is that is not STRONG enough’…Why don’t kiters conclude that the breaking of the leash was a good thing?
Answer: Kiters don’t wear the reel leash on their ankle or wrist, or I think that they would conclude that it was good that the leash broke, when it did. Instead the leash is attached to the harness, and the harness is attached to the kite… and the source of the force on the leash is the power supplied by the kite. The kiter’s role in this system of lines and power supply can be viewed as simply …”ballast”… so the kiter never feels the extreme forces from the resistance of the board loading up due to the action of it “tombstoneing” or “fish-luring” of the board in the water.
If all of the injuries, shown in the pictures, were due to this one factor…that of the extreme ‘loading-up’ of the leash webbing material, then, I suspect that most of these injuries could have been prevented by the insertion of a “tension-triggered” automatic release, into the leash design. Many different “fuse” or “breakable link” designs have been suggested on this and other kite forums…everything from a piece of string with a breaking rating of 50 kilos…to straps of Velcro…to 50 pound rated zip-ties…to plastic snap shackles…to a design, suggested by the forum member ‘Kamikuza’ involving the use of bungee and quick-release. I favor Kamikuza’s suggestion, and have created and tested such a device. Some time in the future, I will present the results of this design and the on-the-water testing of this project.
I wonder how many of the injuries, shown in the pictures would have been prevented by the use of a “tension-triggered” automatic release? I would like to see the “paper work” on each of these injuries…that is a description of the type of leash each victim was wearing, and a play-by-play description of what happened. I would be surprised if many detailed accounts of such incidents were available, however, due to the fact that this kind of incident happens quickly and is rarely witnessed. Also, things are happening too fast for the victim to remember much of anything, and head wounds may result in amnesia.
The loading-up effect of a board leash may be a major factor in most board leash injuries, but I suspect that there are other ways that a board leash can result in injuries. For instance, a friend told me that she broke a rib once when she jumped and the board came off and remained in the landing zone, resulting in a situation which would have been less likely, without a leash. I have heard of other incidents where the leash got wrapped around the kiter, or the board went through the lines, like a bobbin on a weaving loom, leaving the board in an awkward position.
I wonder how likely it would be to receive an injury from a board, simply swinging on the end of a leash, as the kiter performs a jump where the board slips off the kiters feet…it would seem more likely to happen on big jumps, air jibes, or beginners practicing back rolls.
When an injury from a board leash is made public on forums such as Kiteforum, rarely is there a description of the incident, and usually the incident is posted by someone other than the victim… along with the standard warning.
If a kiter chooses, for some reason, to use a certain type of board leash, there are some obvious things that the kiter can do to decrease the risk of severe injury, such as:
(1) Don’t hook up the leash until you are in the water
(2) Don’t use sharp edged fins
(3) Don’t attempt to learn tricks
(4) Use a board without sharp or serrated (from wear and tear) edges
(5) Wear protective gear
(6) Attach the leash to the board in a manner which minimizes the likelihood of the board “tombstoning”
(7) Incorporate a “breakable link” into the leash
(8) Attach the leash to the harness with a “push-away” quick release
(9) Attach the leash to the board with a quick release
(10) Use the appropriate length leash for the conditions, such as wave riding, long-distance crossings, flat water, etc.
These suggestions are only a few of many ideas that may be able to make a certain type of leash “safer”, but of course, no board leash will be a “safe leash”."
im a big of the muppets... 
, there are properly so many pictures of people injured from kiting on the internet (just look a pros knees) and they don't even use a leash…..