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DCB M41 Widebody Cat to be Offered With or Without Center Pod

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Old 02-09-2012, 01:09 AM
  #31
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Originally Posted by RiverDave View Post
That sounds great and all except there's a few problems with it.

I.E. the "Tunnel Tab" would be a great argument here.. Most people think a Tunnel Tab is to help a boat get on plane or reduce porpouse. It's not, and can actually be a ridiculously dangerous if you're driving around with it down and water fills the tunnel and hits it.

In a true tunnel application, what the tab is actually for,(when racing) if the water is smooth enough they can drop that tunnel tab and raise "tunnel compression" lifting the boat further out of the water (hydrodynamic drag is greater then the aerodynamic losses) and pick up quite a bit of speed.

On some models of boats with pods out here on the West Coast they are equipped with 2 smaller tunnel tabs to create the same effect. Problem is people try to use them as trim tabs and end up barrel rolling boats every now and again.

That in itself kind of blows the sticking anything in the tunnel will slow ya down theory.

BTW for efficiency purposes.. Eliminator Daytona (Pod Boat) single Merc 502 (415HP if memory serves?) with a black hawk drive ran in the mid 90's..

Talon with a single HP 500 is upper 90's? (I think Hustler actually claims 100mph?)

RD
Tunnel tab ??? I would never put a tunnel tab on one of my cats ever , the "work" is done before the boat is built but I stay on the design specific side,not one size fits all.

A pod can never be more efficient than a properly designed tunnel. hell we have run 90s at 36 feet on 400 HP, LMAO how do you go faster with more resistance?

Last edited by Steve 1; 02-09-2012 at 01:12 AM.
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Old 02-09-2012, 01:20 AM
  #32
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Lets see;Now if I put a blockage in the Tunnel here on this Cat ,it would have run faster?? a Magic Pod?? Magic water? Running in a vacuum?

http://www.youtube.com/watch?v=h1csGLgX4tk
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Old 02-09-2012, 01:24 AM
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Lets see;Now if I put a blockage in the Tunnel here on this Cat ,it would have run faster?? a Magic Pod?? Magic water? Running in a vacuum?

http://www.youtube.com/watch?v=h1csGLgX4tk
Do you have a video of something that wasn't filmed from a handicam off the screen of an old tube TV and is actually in this millenium?

RD

Last edited by RiverDave; 02-09-2012 at 01:30 AM.
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Old 02-09-2012, 01:32 AM
  #34
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Do you have a video of something that wasn't filmed from a handicam off the screen of an old tube TV and is actually in this millenium?

RD
LMAO That was video off a chopper, NOW your turn ,,,,put up your Magic "Pod" winning the Offshore World Championship!! But you need BOTH a American Championship and a UIM World Title with the same boat as well ,to play here!
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Old 02-09-2012, 03:25 AM
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LMAO That was video off a chopper
I figured I made my point with the dinosaur joke, but ya missed it. That video was filmed by some guy reliving 1989 with a handicam pointed at his old Tube TV set playing a worn out VHS tape.
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NOW your turn ,,,,put up your Magic "Pod" winning the Offshore World Championship!! But you need BOTH a American Championship and a UIM World Title with the same boat as well ,to play here!
You're right. I do not have an american championship or a UIM world title.. But I did spend the night in a holiday inn once? And it wasn't back in the cocaine cowboy days of miami, so I guess it is what it is.

If you don't think you can increase speed on a boat via a tunnel tab, or raising tunnel compression you're misinformed. Certain Pod boats are not just raising tunnel compression, but adding "stability" with hydrodynamic lift across 3 surfaces.. Other pod boats (very raised Center pods) are raising tunnel compression with an aerodynamic surface that also helps with buoyancy and rolling over on plane (without the inherant dangers of a giant tab at a steep angle of attack that a roller can hit at speed), some are a mixture of both actually taking advantage of the water being shot into the tunnel off the sponsons and creating a little lift off that as well, etc.. etc..

There's a little more thought that goes into the center pod for the good mfg's then "Hey lets shove a giant brick down the middle of this thing and sell it." Or in your case "Hey lets deflect the water from our center outboard.. Oh we lost speed, all center pods must suck now."

These guys have been testing and dialing in their bottoms in some cases for 30 years. With the invention of the "go pro" camera the smart guys are sticking them in the tunnels facing backwards to actually see what is going on down there. Before the go pro, the high end guys would stick several pressure ports in the tunnels and data log pressures of what's going on and where down in the tunnels.

Example of a view on Bill Auberlin's 32 Spectre (true tunnel) at 170 mph, only vid I could find on youtube.

http://www.youtube.com/watch?feature...&v=mP-m2qdthEM

Here I'll throw ya for another loop, what some have found out is at a relatively low PSI of tunnel compression (true tunnel or not), the air will actually create a cushion (high pressure zone) out in front of the running boat and a lot of the air you think would be going in the tunnel is actually being pushed over the top and around the sides of the boat which means there's a lot more to be had in making the deck designs more stream lined.

But lets say you're right and there's no benefit, then at least 50 mfg's of performance orientated boats on the West / East Coast / and in between are all doing it wrong and are idiots.. Guys like Bob Leach @ Eliminator, DCB, American Offshore, Hustler, Magic, Conquest, etc.. Think about that for a second.. How many thousands of boats and millions of dollars into tooling, and all of them are 100% wrong according to you. Arrogance isn't even the right word for that line of thinking.

There are benefits to a POD (in smooth water applications), and there are benefits (speed, getting on plane, curing a porpouse in smooth water) and dangers of a Tunnel Tab.. It is undeniable. As well there are benefits to a true tunnel!

3 quick thoughts.. 1. when you won those titles did Tunnel tabs even exist? 2. have you ever experimented with one on a true tunnel. 3. Have you ever experimented with a real deal "pod" as opposed to just trying to deflect water away from an outboard?

If you're going to build a boat for big water, build a true tunnel every time.. (which in offshore racing is what you would want) But to say there's no benefits to be had from a center pod on an inland water way (or smoother conditions) is incorrect, and I don't care how many titles you have.. They aren't applicable to the conversation.

All that being said, even though I'm a West Coast guy and I understand the Pod and some of the thought processes that go in them (I'm no expert by any means). If I was gonna haul ass, I'd want the true tunnel, I think they handle better at the higher speeds, and more useful because you can run them dual purpose in the ocean and on the lake. However I wouldn't look down my nose at a pod boat and call it inferior, because there are times when they are in fact better.. Like say a single engine application on a 28' or less. How the hell would you even build that with a true tunnel?

I expect all that typing probably changed your mind not even a little bit, so needless to say I'm done talking about it. I don't think your views will change, and let me tell you for a fact mine aren't gonna.. So we should agree to just disagree and move forward.

RD

Last edited by RiverDave; 02-09-2012 at 04:17 AM.
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Old 02-09-2012, 08:06 AM
  #36
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I figured I made my point with the dinosaur joke, but ya missed it. That video was filmed by some guy reliving 1989 with a handicam pointed at his old Tube TV set playing a worn out VHS tape.


You're right. I do not have an american championship or a UIM world title.. But I did spend the night in a holiday inn once? And it wasn't back in the cocaine cowboy days of miami, so I guess it is what it is.

If you don't think you can increase speed on a boat via a tunnel tab, or raising tunnel compression you're misinformed. Certain Pod boats are not just raising tunnel compression, but adding "stability" with hydrodynamic lift across 3 surfaces.. Other pod boats (very raised Center pods) are raising tunnel compression with an aerodynamic surface that also helps with buoyancy and rolling over on plane (without the inherant dangers of a giant tab at a steep angle of attack that a roller can hit at speed), some are a mixture of both actually taking advantage of the water being shot into the tunnel off the sponsons and creating a little lift off that as well, etc.. etc..

There's a little more thought that goes into the center pod for the good mfg's then "Hey lets shove a giant brick down the middle of this thing and sell it." Or in your case "Hey lets deflect the water from our center outboard.. Oh we lost speed, all center pods must suck now."

These guys have been testing and dialing in their bottoms in some cases for 30 years. With the invention of the "go pro" camera the smart guys are sticking them in the tunnels facing backwards to actually see what is going on down there. Before the go pro, the high end guys would stick several pressure ports in the tunnels and data log pressures of what's going on and where down in the tunnels.

Example of a view on Bill Auberlin's 32 Spectre (true tunnel) at 170 mph, only vid I could find on youtube.

http://www.youtube.com/watch?feature...&v=mP-m2qdthEM

Here I'll throw ya for another loop, what some have found out is at a relatively low PSI of tunnel compression (true tunnel or not), the air will actually create a cushion (high pressure zone) out in front of the running boat and a lot of the air you think would be going in the tunnel is actually being pushed over the top and around the sides of the boat which means there's a lot more to be had in making the deck designs more stream lined.

But lets say you're right and there's no benefit, then at least 50 mfg's of performance orientated boats on the West / East Coast / and in between are all doing it wrong and are idiots.. Guys like Bob Leach @ Eliminator, DCB, American Offshore, Hustler, Magic, Conquest, etc.. Think about that for a second.. How many thousands of boats and millions of dollars into tooling, and all of them are 100% wrong according to you. Arrogance isn't even the right word for that line of thinking.

There are benefits to a POD (in smooth water applications), and there are benefits (speed, getting on plane, curing a porpouse in smooth water) and dangers of a Tunnel Tab.. It is undeniable. As well there are benefits to a true tunnel!

3 quick thoughts.. 1. when you won those titles did Tunnel tabs even exist? 2. have you ever experimented with one on a true tunnel. 3. Have you ever experimented with a real deal "pod" as opposed to just trying to deflect water away from an outboard?

If you're going to build a boat for big water, build a true tunnel every time.. (which in offshore racing is what you would want) But to say there's no benefits to be had from a center pod on an inland water way (or smoother conditions) is incorrect, and I don't care how many titles you have.. They aren't applicable to the conversation.

All that being said, even though I'm a West Coast guy and I understand the Pod and some of the thought processes that go in them (I'm no expert by any means). If I was gonna haul ass, I'd want the true tunnel, I think they handle better at the higher speeds, and more useful because you can run them dual purpose in the ocean and on the lake. However I wouldn't look down my nose at a pod boat and call it inferior, because there are times when they are in fact better.. Like say a single engine application on a 28' or less. How the hell would you even build that with a true tunnel?

I expect all that typing probably changed your mind not even a little bit, so needless to say I'm done talking about it. I don't think your views will change, and let me tell you for a fact mine aren't gonna.. So we should agree to just disagree and move forward.

RD
Once again! Increasing, “Resistance” does not increase speed, Christ if your theory Held water or air, the winning boats at smoke on the water (Lake) would have a Few Pods clogging their tunnel and for that matter Aircraft would look vastly different than they currently do! Like a Brick! The IDEA is to have the “Right” tunnel and bottom in the first place for the boat’s weight.

Yes , I designed and built IT in the early 90’s ,the Tunnel and Bottom Both were developed by the “projected mass” Listening ?? Now It went from MY shop to Key West UNTESTED, Never WET and WON, With a very clean Tunnel, WHY ?? Because I wanted to prove a point, The Boat was Design Specific!

You see I do not give a Damn what anybody else was doing, two reasons, One I have my own numbers and Ideas, Second Never copied anyone and never ever will.

Why this is a touchy issue with me , because, all through the building process, THE “experts” would stop by (I had a open shop policy) and “that will not work” and “why not do this instead” But I stuck to my Plans and Proved them all wrong. BTW that Model 8, 10 meter Boat in my Avatar, Designed and built in secret ,Pulled out and Won the first race in Kuwait after the War.
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Old 02-09-2012, 08:10 AM
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Steve,
You obviously know a lot about tunnel hull design. Do you think you would be able to meet DCB's west coast customer bases demand with a true tunnel design? I think it would be tough. What would your hull look life if your customer demands were:
-wants 30's in size with twins IO
-needs good low speed manners, needs to maneuver comfortably 40-60mph, since will be used mainly in crowded narrow lakes
-needs room for 4-5 adults, kids, the dog, big cooler, 5 amps.
-has to have a cabin with a couple of benches and pad big enough for 2, the wife won't have it if it doesn't have a cabin
-some may require an open bow
-needs to look sleek and racey
-needs to be a 9'beam to be trailerable and fit inside a garage
-customer thinks it should run 130's with 700's
I ask this with the utmost respect, because I'm not sure it could be done with cg forward. If you could meet this criteria, it would be huge for us all.
-

Last edited by SkiDoc; 02-09-2012 at 08:12 AM.
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Old 02-09-2012, 09:00 AM
  #38
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Steve,
You obviously know a lot about tunnel hull design. Do you think you would be able to meet DCB's west coast customer bases demand with a true tunnel design? I think it would be tough. What would your hull look life if your customer demands were:
-wants 30's in size with twins IO
-needs good low speed manners, needs to maneuver comfortably 40-60mph, since will be used mainly in crowded narrow lakes
-needs room for 4-5 adults, kids, the dog, big cooler, 5 amps.
-has to have a cabin with a couple of benches and pad big enough for 2, the wife won't have it if it doesn't have a cabin
-some may require an open bow
-needs to look sleek and racey
-needs to be a 9'beam to be trailerable and fit inside a garage
-customer thinks it should run 130's with 700's
I ask this with the utmost respect, because I'm not sure it could be done with cg forward. If you could meet this criteria, it would be huge for us all.
-
Doing a quick look at it,I got the speed very close with everything imaginable onboard , the Beam is a non Issue and the CG with inboards can be made user friendly with a little thought given on the Sponsons, the cabin will require some freeboard added but not that much and the open bow is not a big deal ,half a open fisherman so to say.
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Old 02-09-2012, 01:28 PM
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Once again! Increasing, “Resistance” does not increase speed, Christ if your theory Held water or air, the winning boats at smoke on the water (Lake) would have a Few Pods clogging their tunnel and for that matter Aircraft would look vastly different than they currently do! Like a Brick! The IDEA is to have the “Right” tunnel and bottom in the first place for the boat’s weight.

Yes , I designed and built IT in the early 90’s ,the Tunnel and Bottom Both were developed by the “projected mass” Listening ?? Now It went from MY shop to Key West UNTESTED, Never WET and WON, With a very clean Tunnel, WHY ?? Because I wanted to prove a point, The Boat was Design Specific!

You see I do not give a Damn what anybody else was doing, two reasons, One I have my own numbers and Ideas, Second Never copied anyone and never ever will.

Why this is a touchy issue with me , because, all through the building process, THE “experts” would stop by (I had a open shop policy) and “that will not work” and “why not do this instead” But I stuck to my Plans and Proved them all wrong. BTW that Model 8, 10 meter Boat in my Avatar, Designed and built in secret ,Pulled out and Won the first race in Kuwait after the War.
Well mr Steve I'm not sure what to tell you.. Enjoy living in 1992.

RD
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Old 02-09-2012, 03:01 PM
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Well mr Steve I'm not sure what to tell you.. Enjoy living in 1992.

RD
Damn, just can’t let this go can you?? Ok Since I was a Quarter century ahead of YOU in Knowledge of how a Cat works, Plus Design, and Composite work,No problem.
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