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"You call that a KNIFE, Mate"?

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tomatkins
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"You call that a KNIFE, Mate"?

Postby tomatkins » Thu Aug 30, 2007 4:53 pm

Naaah, Mate....this is a knife!

My new hook knifes just arrived. Rick described the knife and the source in this thread:

phpbb/viewtopic.php?t=2341425&start=0&p ... highlight=

Thanks for the "heads-up" on this new knife, Rick. It looks like it should do the trick, if I get tangled in lines.


I purchased the knifes for about $15. each from:

http://www.austinsdiving.com/homepage/


I have modified my helmet to accommodate this larger knife. I will test this new arrangement, and report back if I find any problems with it. I have experimented with different locations for carrying hook knives....over the heart, on the cuff, in a pocket glued to the top of the helmet, in pockets on the harness, etc...and I favor this location in the back of the helmet, for ease of access, and minimal tangling risk. The cutting away of a small amount of foam, probably voids the warranty of the helmet, and slightly reduces the protection by the helmet, but I evaluated the risk, made a decision, and chose to do this. Here are 2 links to threads which give a good discussion and criticism of this modification:

phpbb/viewtopic.php?t=2320414&highlight=hook+knife


phpbb/viewtopic.php?t=2333430&highlight=hook+knife


Here are 2 self-explanatory pictures:
Attachments
kf- hook knife sizes.JPG
kf- hook knife sizes.JPG (116.3 KiB) Viewed 2613 times
kf-lhook knife helmet.JPG
kf-lhook knife helmet.JPG (115.97 KiB) Viewed 2613 times

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klimber
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Postby klimber » Thu Aug 30, 2007 5:16 pm

I can't even comprehend that this is the best place to store your knife. right next to soft access to the brain stem?

wjb
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Postby wjb » Thu Aug 30, 2007 5:54 pm

It seems that reaching toward your chest or your hip would be a more natural move then behind your head in a crisis situation. Also a possible line tangle vs reducing the effectiveness of you helmet is not a tradeoff I would be willing to make. I like the position of the Mystic knife, right at your hip.

tomatkins
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Postby tomatkins » Thu Aug 30, 2007 6:07 pm

klimber wrote:I can't even comprehend that this is the best place to store your knife. right next to soft access to the brain stem?
I guess, that in an accident, so severe as to push a thick piece of plastic, covered with a half inch of heavy foam padding, through a layer of bone or ligament, into your brain stem, then, the forces involved in that accident would be so severe as to possibly shatter your helmet and drive the pieces of plastic into your brain stem, also. One could then make a weak case that the helmet, itself, is a potential danger. Lets face it, this type of helmet is not designed to be extremely protective, and in effect, offers no protection at all to the vulnerable neck area. At best, this type of loosely fitting helmet is designed to prevent lacerations to the scalp, and to absorb enough of a blow to prevent a wearer from being knocked unconscious, and to give enough cushioning to minimize impact shaking of the brain. As minimal as the protection is, it is probably adequate for types of impacts, likely to be encountered in our sport.

I considered the idea that you present, and feel that the helmet would most likely be ripped off the head, before the scenario you refer to would occur. The little plastic buckle that holds it on is not very strong. This helmet is not designed like a motorcycle helmet, and probably offers protection only from impacts, which, although damaging to an unprotected skull, are really, in the overall scheme of things, relatively minor force impacts. Of course, I would prefer wearing a properly engineered and designed helmet, which would be reinforced in all the right spots, but I don't think it is likely that one will be produced.

Here is a picture of the inside of the helmet, showing the thickness of foam still overlying the hook knife.

Klimber,

Thanks for the critical look at this proposal. You have presented the best case for not carrying the knife in this location, so far. An external location would be better, or at least a helmet designed with an extension of the occipital region of the helmet to cover the neck area, giving a solid area of protective helmet plastic, between the skin and the handle of the knife. Let's see if we can design one!
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kf- helmet foam inside.JPG
kf- helmet foam inside.JPG (125.38 KiB) Viewed 2493 times

viktor
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Postby viktor » Thu Aug 30, 2007 6:27 pm

I think you should go Freddy Cruger style :)

tomatkins
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Postby tomatkins » Thu Aug 30, 2007 7:04 pm

wjb wrote:It seems that reaching toward your chest or your hip would be a more natural move then behind your head in a crisis situation. Also a possible line tangle vs reducing the effectiveness of you helmet is not a tradeoff I would be willing to make. I like the position of the Mystic knife, right at your hip.
The reason I settled on carrying the hook knife on the back of the helmet was the following:

(1) The likely scenario for needing the knife is one where the kiter is relentlessly being dragged behind a looping kite which may be crashing and then, relaunching. The kiter is hanging on for dear life to the kitebar. this may be occuring on the water, deep or shallow, on dry land, through brush, rocks, etc. The kiter is being turned "every way but loose", taking hits at times to his front, side and back.

(2) Any piece of emergency equipment located on the kiters chest, hip or backside is in danger of being fouled in seaweed, sticks, other kiters equipment, etc.

(3) The kiter will probably only have one opportunity to make a grab for the emergency equipment (in this case, a hook knife), and this "grab" must be done quickly, smoothly, and unimpeded by debris or loose pieces of his own equipment.

(4) The shortest distance that the kiter's hand needs to travel in such a scenario can be illustrated by having you, right now, put both hands up above your head, as though you are holding onto a kitebar, and imagineing that you are being dragged, chest-and-head-first by an out of control looping kite, directly downwind. Now, pretend that you are reaching for the hook knife, located at the back of the helmet. The motion is the following:

(5) The chosen hand (either one works equally well) releases its grip on the bar, and simply bends at the elbow, arriving, in a split second, at the back of the helmet, where the handle of the knife is encountered at the rim of the helmet...no searching involved...just follow the rim of the helmet.

(6) At the moment the kiter has chosen to grab the knife, he will most likely be laying in the stomach-down position, but thankfully, due to the upward pull of the kite, his face will not be dragging in the surface, and most likely, there will be free space between his hand on the kitebar and the back of his helmet.

The best case, I can make for carrying the hook knife in this location, is the location has the best access to the knife in a realistic scenario. None of the other locations, where I have carried the knife, in the past, satisfied this "best access" test in a realistic scenario.

I will not put forth a dramatic scenario, where a knife, carried in the common over-the-heart location, is accidentally, durring a dragging situation, where through the force of encountering an immoveable opject, the knife is, thereby, driven into the heart. That would be overly dramatic! This common over-the-heart location is where EMTs and other rescue workers seem to prefer for access to their knives, along with parachutists, and other recreationalists. These individuals have specific reasons for carrying their knives in this location, accessible to them in their likely emergency scenarios, but I would make the case that, with the activity of kiteboarding, that the likelihood of needing quick access to the knife, while being dragged in the head first position, is paramount. Let's be practical and cover that base first.

There is a lot of valuable opinion in the other threads that I listed above, and they are worth reading, if this subject interests anyone else. The subject deserves a lot of thought...at least by "safety conscious" kiters who, unlike the majority of kiters, would not even consider wearing a helmet or carrying a hook knife. Even though we are in the minority, let's see if we can find the best answer to this problem. All opinions need to be welcome, and analyzed, and this forum is the best place in the world to do it.

tomatkins
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Postby tomatkins » Thu Aug 30, 2007 8:27 pm

wjb wrote:
reducing the effectiveness of you helmet is not a tradeoff I would be willing to make. I like the position of the Mystic knife, right at your hip.
wjb,

You may be giving the helmet you wear more credit than it deserves. I haven't seen a properly designed "kiteboarding helmet" yet.
The helmets almost everyone wears have been designed for:

(1) Kayaking...The emergency scenario in that sport (I'm a long time kayaker, myself) is where you are you are hanging upside-down from the kayak in a fast-moving, shallow river, taking hits on the helmet from the rocks on the bottom.

(2) Windsurfing...The emergency scenario in that sport (again, I'm a long time participant) is from blowing your tack and getting tomahawked on the top of the head by a fast-falling mast.

(3) Bicycling...The scenario there is where the rider falls and gets his head whipped down flat onto the pavement.

On the other hand, a specifically designed Kiteboaring helmet would protect the rider from the likely scenarios, we encounter on the water and on the beach. Events like: (a) Rider surfaces and his face, neck or top of head encounters a fast moving loose kiteboard, gliding down the wave, or being slingshoted by a board leash, where the sharp edge of board or fin causes a laceration, (b) Rider is entangled in lines and needs to have the lines not tangle on buckles, or undercuts or edges of the helmet.

For one thing, a true kiteboarding helmet needs to cover a lot more of a kiters head and neck than any of the above substitute helmets. The kayaking and windsurfing helmets design assume the blow will be to the top of the head, and the bicycle design allows the helmet to slightly rotate over the ears, neck or forehead on impact. I won't try to analyze the many other differences.

So, the case I am trying to present is that: A kiter is already wearing a necessary, but in reality, a poorly designed piece of protective equipment for the particular activity, so, weakening, by a small amount, (ie removing a little bit of the padding) the overall effectiveness of the equipment, is not decreasing the true safety value of the piece of equipment, a whole heck of a lot. By doing so, if the kiter makes another aspect of the kiting activity significantly safer (ie being able to effectively cut himself out of a tangle of lines), then, the trade-off may be worthwhile.

Lots of room for other opinions here, and I welcome all criticism.

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Postby wjb » Thu Aug 30, 2007 9:16 pm

Maybe a better location would be little off to the side towards the front of the helmet where you could reach up and grab the knife with your dominate hand . You could then bring the knife down possibly cutting the offending line with one stroke. With the knife in the back it just seems awkward to retrieve and if your helmet was knocked from the front the knife handle may press into you neck. Snag proofing a helmet with the knife on top would be a challenge though.

tomatkins
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Postby tomatkins » Fri Aug 31, 2007 1:29 am

wjb wrote:
Snag proofing a helmet with the knife on top would be a challenge though.
wjb,

I agree that the best place would be on the top of the helmet, and indeed, for about a year, I carried my hook knife in a little compartment which I taped to the top of the helmet with electrical tape. It worked OK, but looked odd, and then one day when I was catching a Flysurfer kite, the filamentous bridle line got tangled on the knife compartment, jerked my head, and scared me.

Wouldn't it be nice to see a properly designed kiteboarding helmet for sale, with features like a smooth molded compartment for the hook knife, along with proper coverage of the skull, forehead and neck, and with non-line-snagging buckles. That is the subject for a whole new thread on Kiteforum.

Also, I just got back from kiting using my new and even more modified helmet. Klimber's comment made me put some additional thought into the possibility of the handle of the knife pressing into the back of the spine, so I added added another half inch of high density foam to separate the back of my neck from the smooth flat handle of the knife. I feel that this extra padding makes the arrangement slightly safer, and also, as a bonus, makes the helmet fit tighter. Here are a couple of pictures of this "work in progress".
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kf- neck pad.JPG (124.01 KiB) Viewed 2145 times
kf-neck pad 2.JPG
kf-neck pad 2.JPG (118.78 KiB) Viewed 2145 times

RichardL
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Postby RichardL » Fri Aug 31, 2007 1:46 am

Hey tomatkins, is this topic referring to the movie i'm thinking of? Aussie outback? That was a truly horrible (as in but good) movie.


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