Step Bottom History
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12-12-2002, 01:23 PM
#172
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Anyone who read my post before I edited it, please accept my apology for going WAY over the line and do not let any more of it into the thread. I sent an apology to the party I mentioned and hope we can all respect his feelings.
Sincerely,
Tom
Sincerely,
Tom
12-12-2002, 03:31 PM
#173
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Originally posted by T2x
Tom:
During the early OPC race years( 1960-80) horizontal steps(todays topic) were illegal on Factory vee hulls, so there was a curiosity around their speed potential (That's basically why George and I experimented with them in 1981). This rules logic dated back to the early race craft pictured above in this thread, and at the Antique Race events. Since they worked to some extent in speeding up Gar Wood, they were always considered a speed increasing appendage, or modification.....( in some cases they were actually added on to an existing hull). They undeniably do two things. (1)Create a break in the planing surface for better or worse and (2)introduce bubbles or voids in the area immediately aft of their placement (If not sufficiently ventilated to allow this, they actually reduce speed through drag and vacuum effects). My points, as you said, are based around these two phenomenon. (1) The speed increases, at best, are illusive and, at worst, non existent. (2) The loss of contact with the water surface and the introduction of air create an unacceptably slippery condition in turns, thereby contributing to spinouts and increasing the degree of difficulty in proceeding through corners.
Tom:
During the early OPC race years( 1960-80) horizontal steps(todays topic) were illegal on Factory vee hulls, so there was a curiosity around their speed potential (That's basically why George and I experimented with them in 1981). This rules logic dated back to the early race craft pictured above in this thread, and at the Antique Race events. Since they worked to some extent in speeding up Gar Wood, they were always considered a speed increasing appendage, or modification.....( in some cases they were actually added on to an existing hull). They undeniably do two things. (1)Create a break in the planing surface for better or worse and (2)introduce bubbles or voids in the area immediately aft of their placement (If not sufficiently ventilated to allow this, they actually reduce speed through drag and vacuum effects). My points, as you said, are based around these two phenomenon. (1) The speed increases, at best, are illusive and, at worst, non existent. (2) The loss of contact with the water surface and the introduction of air create an unacceptably slippery condition in turns, thereby contributing to spinouts and increasing the degree of difficulty in proceeding through corners.
I thought this addressed the step spinout tendencies pretty clearly. However, let me add that it is not beyond the realm of possibility that properly designed and installed anti skid fins or surfaces coupled with a sane and realistic prop rotation on twin engine applications(spinning out) could decrease the loss of directional stability in turns created by steps. But,.......... again, why go through all of that just to wind up with the turning adhesion you had with non stepped bottoms in the first place?
T2x.........................looking back fondly on Molinari's
12-12-2002, 04:02 PM
#175
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Very well written Tom and enlightening. I didn't read your unedited post so I hope it wasn't me you vented on.
If you haven't already, go back and read "Great Moments in V bottom History" before it slips away into oblivion again. There's tons of info, history and down right stubborness concerning steps vs V hulls. The spin-out/roll thing is addressed as well. Better fill a big bowl of popcorn though, it's rather lengthy...
If you haven't already, go back and read "Great Moments in V bottom History" before it slips away into oblivion again. There's tons of info, history and down right stubborness concerning steps vs V hulls. The spin-out/roll thing is addressed as well. Better fill a big bowl of popcorn though, it's rather lengthy...
12-12-2002, 04:05 PM
#176
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Originally posted by Tom
If people can get grants to study how a hummingbird flies, why can't a student study hydrodynamics of performance boats?
If people can get grants to study how a hummingbird flies, why can't a student study hydrodynamics of performance boats?
On the other hand various people have conducted many full scale tests with actual boats. The technique involves taping on wind directional indicator ribbons and some rudimentary aerial photos. All in all, this is probably a better technique than a static wind tunnel.
I believe what frustrates many of the older more "experienced" contributers to this board is the constant re-invention of the wheel and "discoveries" of old wine in new bottles that we are faced with by today's manufacturers, many of whom were'nt around the last time their new "concept" crashed and burned on the race course.
This morning I heard a DJ introduce a nice version of the tune "Love Hurts" by Joan Jett. He was corrected by his comrade who informed him that it was actually a cover of the song originally recorded by some other New Age group at a faster tempo about 10 years ago, and this "new version" was actually an "improvement". I shrugged my shoulders........... remembering the true original ..........recorded at the "new" tempo and much better........................by The Everly Brothers back in 1961 or so.
The big difference with this topic is that, unlike a stupid misunderstanding about an old song......... ill advised hull modifications can hurt, maim, or worse......... kill you.
Spinning out, while interesting to watch,.......... can break your neck. Stuffing without proper safety restraints can do the same. While safety canopies and restraints are much better now with each passing year, even Nascar doesn't advocate a car designed to bounce off the protective concrete walls as a valid way of keeping it on the race course. Any stuff or spinout should be avoided at ALL costs. You can lose control, hit someone else's boat, get hit by loose objects in your cockpit....or, in the worst case scenario, hyper extend your spine and separate it from your skull. This is called a Basel Skull fracture and is covered elsewhere in threads on the board........ It's a rapid deceleration phenomenon.....and it is what killed Mark Lavin......and damn near did the same to Bobby Saccenti....... cherished friends of mine.
Not all criticism is about personal preferences....or prejudices.
T2x
Last edited by T2x; 12-12-2002 at 06:35 PM.
12-12-2002, 06:21 PM
#177
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T2X,
Well stated. Do you think the HANS Device could help, or do you think it would be more of a hindrence to the racers due to neck restrictions? We looked at them at the PRI Show in Indy last weekend and they brought up interesting conversation at our table.
Chris
Well stated. Do you think the HANS Device could help, or do you think it would be more of a hindrence to the racers due to neck restrictions? We looked at them at the PRI Show in Indy last weekend and they brought up interesting conversation at our table.
Chris
12-12-2002, 06:31 PM
#178
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The Hans device certainly would help..... The biggest obstacle will be racer comfort......and old habits......
The bigger problem has to do with the Pleasure/Poker Run crowd who can hardly be expected to wear items such as these...... Even though they, in many cases are going at equally or greater ballistic speeds than today's somewhat de-fanged raceboats.
Armed only with a bikini and a bank account, my fear is that these are the most innocent potential victims of misplaced hull trends. Not necessarily the good ol' boy owners...... rather, the passengers who in many cases are just eager to go for an exciting days recreational jaunt....and are little more than flailing projectiles when things go horribly wrong at a buck and a quarter.
T2x............on his sturdy, time worn soap box
The bigger problem has to do with the Pleasure/Poker Run crowd who can hardly be expected to wear items such as these...... Even though they, in many cases are going at equally or greater ballistic speeds than today's somewhat de-fanged raceboats.
Armed only with a bikini and a bank account, my fear is that these are the most innocent potential victims of misplaced hull trends. Not necessarily the good ol' boy owners...... rather, the passengers who in many cases are just eager to go for an exciting days recreational jaunt....and are little more than flailing projectiles when things go horribly wrong at a buck and a quarter.
T2x............on his sturdy, time worn soap box
12-12-2002, 09:58 PM
#179
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HANS device?
Chris + T2x,
Sorry to remind you again of my ignorance, but what is a HANS device? I won't go out without helmets, foam collars and lifelines, maybe HANS devices should become an old habit too.
T2x, Sorry I forgot you had previously put it so very well, but at least I paraphrased it fairly accurately.
I was going to ban myself for a week, but todays posts were so great I just had to give my compliments. I think any more attempts on my part to stuff it takes me from ignorant to stupid. I guess the article in Powerboat that remarked about stuffing the batboat lead me very astray.
Sorry to remind you again of my ignorance, but what is a HANS device? I won't go out without helmets, foam collars and lifelines, maybe HANS devices should become an old habit too.
(1)Create a break in the planing surface for better or worse and (2)introduce bubbles or voids in the area immediately aft of their placement (If not sufficiently ventilated to allow this, they actually reduce speed through drag and vacuum effects). My points, as you said, are based around these two phenomenon. (1) The speed increases, at best, are illusive and, at worst, non existent. (2) The loss of contact with the water surface and the introduction of air create an unacceptably slippery condition in turns, thereby contributing to spinouts and increasing the degree of difficulty in proceeding through corners.
I was going to ban myself for a week, but todays posts were so great I just had to give my compliments. I think any more attempts on my part to stuff it takes me from ignorant to stupid. I guess the article in Powerboat that remarked about stuffing the batboat lead me very astray.
12-12-2002, 10:19 PM
#180
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Hans stands for head and neck support. Nascar has been kicking around the idea of madating them for quite a while. The drivers say it restricts their ability to look around.
