I disagree with your statement. If the board is banked into the turn (i.e. a rotation of the board about it’s roll axis), the pressure vector associated with the flow of water on the bottom of the board will have a component directed towards the center of the turn (since the pressure is perpendicular to the bottom of the board). If the bank angle is “properly” chosen by the rider, the forces in the system will be in balance and the turn can be executed without a need for fins. Examples of this condition can be seen in pictures of carving bottom turns on single fin boards in which the fin is visibly out of the water. It is also the type of turn one typically experiences when riding in an airliner that is making a turn. In aviation parlance, this type of a turn is referred to as a “coordinated” turn. If the bank angle is too small, the board/plane slides away from the center of the turn (called a “skidding” turn); too much bank, and the board/plane slides toward the center of the turn (a “slipping” turn–which can lead to “catching the inside rail” on a surfboard). With an airplane, a coordinated turn is “felt” as a downward push into the seat; uncoordinated turns produce a (generally weaker) sideways force in addition the downward force.*
Fins essentially act as “crutches” that help compensate for errors that the surfer may make when trimming or maneuvering on the face of a wave. They do this primarily by slowing down the speed at which small deviations (associated with the errors the rider makes) grow into unmanagable/unrecoverable conditions, thus giving him more time to recover.
Note: Typically a coordinated turn minimizes the loss of energy during the execution of a turn. However, there are times when a greater loss of energy is desirable. An comon example is “slipping” the plane (with “crossed” rudder and ailerons) when a steep descent is desired (e.g. landing at a runway down in a valley). Similarly, “skids” are sometimes deliberately executed by a surfer when making top turns.
While we wait for Herb to come back with some video, I did one a while back where each tube went down into a channel. The round hole was about 1 inch in diameter, drilled straiight down.
I put a plastic door vent over the hole so I wouldnt get my toes broken.
I cant say how effective it ws but I could hear the water sucking air into the vent and I could feel the suction on my toes if I stood on the vent. And it worked at low speeds.
Since Morrey was mentioned on this thread, I thought I’d post a link to an article I came across a while back on some entrepreneurial site that was cribbed from his blog:
Not trying to discourage anyone from pursuing protection for their hard work and creativity - just food for thought on the pros and (in his opinion mostly) cons of patents.
I really love the spirit (and Spirit) of what “Y” says. On the other hand, ask Dale Solomonson how that approach worked out for him w/ Neumatic surf mats. From my experience, Dale is one of the all time, most generous with sharing his knowledge and experience of anyone I have ever met, both inside and outside the “surfing world.”
i came up w/ my superchargers by myself… w/o other influences,just as i created my induction board w/o any other influences.
plus my superchargers are functional… 100%.
i can’t say the same for the c-5.
i’m in the process or building a second sfi…and i’m going to throw in some red-x boxes in the first prototype, to see what differences there are…blab,blab,blab…with xs in the board, i can still ride it finless,and have some new ports to play with.
for now i got to go…i still am having virus trouble…so again…it might be awhile.
herb, how does that board ride compared to ‘regular’ alaias?
btw you may want to switch to a mac when you have the time. transferring files from windows to mac is much easier now, and those bug problems become history too
History is full of what’s called “simultaneous, independent discovery.” Totally independent thinkers, often different steps to almost identical results, or fairly different but still similar endpoints. One of those funny, synchronicity things. Who gets the credit/patent/$ pretty much comes down to politics, initial financial backing, aggression, all that sort of stuff that really does not have anything to do with the original creation; different skill sets.
Besides surfboards, the patent examiner will also cite against you any similar language to your surfboard application among patents for water skis, wake boards, kite boards, skim boards, etc., or almost anything in the sport/toys classification.
sounds interesting " ) any deck diagram / pics showing the vent positions?
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I drew 2 lines where I thought the front water contact lines were and then put 5 holes in a V, the idea was to keep the 3 'wave-side' vents under water.
I just drilled the holes with a 1" spade bit and then ran a rounded channel from the hole out thru the tail. I brushed resin into the holes to waterproof them.
I was more worried about breaking a toe in the holes so the plastic vents were a good idea...[IMG]http://i153.photobucket.com/albums/s225/SURFFOILS/cupboardvent.jpg[/IMG] It looked odd.
these days sometimes it helps that some guys online with the right tools on hand get to post & test the proof-of-concept or prototype first before someone else overseas spends enormous personal resources to test the same idea they came up with independently. in which case if the idea works, the first one to publicize it gets to name and “own” the innovation. a matter of timing IMO
Lance Collins also made about 100 "jet boards" in the 70s by putting a couple of pieces of 3/4" pvc from the deck to the bottom with a step/vent in the bottom. but his idea was to force the air under the board to create lift, which is slightly different than what Morey was trying to do.
I've thought about this subject quite a bit before I ran across this thread.. I've got something on the racks waiting to be glassed that makes people scratch their heads and wonder what I've been smoking... I made a 6'5" that has a 6 (concave) channel bottom that has a 45 degree hole drilled at the head of each of the channels. MY thinking (which might be wrong) is to introduce air into the heads of these channels via the venturi effect by the forward motion of the board so as to lessen the drag and to give it a little boost lift in the tail.. I was planning on having it glassed then have something like 3/8" holes drilled then filled with resin then drill a 1/8 hole through the resin right down the middle the chamfer the holes on the surface side.. The holes in the surface aren't really in a place that ill create much of a hassle for your feet or for a tail pad. I can't afford to have it glassed (I'm on disabllity) so if there is someone in the San Diego area that wants to jump in and have it glassed, it's yours.. All I ask is the ability to photograph it afterwards and get some feedback from the rider... I've never shaped run of the mill boards and have had pretty good luck in the past with everything I've made.. Take a look at the pics and get back to me if anyone is interested..
Robbyson, I tried the tubes drilled perpendicular and at an angle and I found that the angled tubes sucked LESS air. They looked better but didnt work as effectively.
I did a bit more reading about the venturi effect and it said that as the water sheers off the front edge of the tube (red area) it encounters a low pressure of the air in the tube and draws the air down. So the greater the change in pressure the greater the effect. And a square angle gave the greatest change.
My tubes were at least 3/4 in or 1 in, and even with the plastic vent covers you could easily hear the air being sucked/drawn into the tubes. So I dont think that your 1/8 in tubes will be big enough to allow full flow and use of the tube/channel combo.
Thanks for the input, it does make sense on further reflection.. Chalk this one up to experimentation..
I did check out that body board, very cool.. My buddy shaped something similar (not quite as professional though) about 15 years ago.. Has some really interesting channels in the rails (yes, inset into the rails).. He rode it at rather large Sunset Cliffs here in San Diego and loved it.. I may try it this summer since my back issues make it difficult to surf anymore... I might be better off bodyboarding and if I get into it, I may try shaping my own boards...
Robbyson, careful of your back on BB. The extreme hyperextenson position that is the general riding m.o. can really hurt you, esp if you take a lip hit etc. Either ride BB with body more flat down like surf mat, or make wooden paipo/prone alaia that is longer and supports more of torso, or of course, ride a mat!
Thanks! Never been bodyboarding before so wouldn’t know the effects on my old bod. You probably saved me some pain!
I’ve had 7 back surgeries since 2001 and have had 3 discs replaced in my lumbar area, but the freaking doctor shattered my L5 verterbrate like a china plate when he was tightening down the bolt on my lower right titanium rod!
I also have a Neurostimulator intalled (a battery pack with 6’ of electrical wire sewn onto the sheath of my spinal cord. The doc that installed it said it was a shark magnet!
Oh well, I’ve gotta do whatever I can to stay in the water.
Man. I hope Herb gets some video up of him riding his board soon – talking about stepped air-port designs is red herring. Herb’s design ports water through the board to provide hold + he says it works better than finned boards + there are pictures up, for cripes’ sake. Post the vids! Herb! Hey!
I just picked up the finished board from the glasser this morning.. Here's some pictures of the finished product... Can't wait to get feedback on it from who ever wants to ride it (since I can't)..
