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Discussion Starter · #1 ·
The winger vs. V-hull brought up something I've been curious about for a while.


What are the pro's and con's/differences between an air passing tunnel, and an air packing tunnel?


Let's say you had the same HP/Pump/Weight in an Eliminator Scorpion and a Daytona. What are the differences on...


Launch?

330'?

1/8?

1/4?

Lake crusing speeds?

How can you tell the difference between packing and passing hulls by looking at them? or can you?
 

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OH, reading the title I thought this was a GN7 vs bp298 thread. :duh: sorry for the confusion, carry on :D
 

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I came across this patent case from the 1940's-1950's involving hallett. fairly good explanation.
Both defendant's exhibits 1 and 2 are constructed with pontoons on the side in generally the same relative position, but the pontoons in defendant's exhibit 2 are slightly farther apart by comparison. Defendant's exhibit 1 shows a warped bottom. Exhibit 2 has a relatively flat bottom. With the Apel design there is no vacuum under the hull, the main feature with boats of the so-called three point cofiguration is that it allows air to pass under the boat instead of being forced to expel itself out from around the sides of the triangle of the boat; the Apel boat corrected faults in previous designs by removing the planes from beneath the boat and putting them out in the air stream, eliminating the vacuum which would normally exist had they been under the boat, achieving performance in a manner which had never been achieved before. The air is not actually trapped under the hull, it passes freely beneath the hull and makes it impossible for a vacuum to build up.

They go on to say the speed record was 74 miles per hour at the time.

https://bulk.resource.org/courts.gov/c/F2/239/239.F2d.581.15633.html
 

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So if I read that right, air packing is like a southwind that exhausts the air out the sides and transom.
Air passing is like a hydro where the boat rides on a pocket and air flows freely.
Is that correct?
 

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Discussion Starter · #7 ·
I do know that air packing (19 Daytona for example) packs air under the boat causing lift. What I don't know is at what speed. How much does it help. How does it compare to a pickle fork tunnel that doesn't pack air. Etc. Like a side by side comparison.
 

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this may be a better asked question in the outboard section do to the fact that scorpions were designed for an outboard. I only know of one on here that runs well as a jet and thats madskillz boat, maybe he could fill you in regarding this type of hull.
 

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this may be a better asked question in the outboard section do to the fact that scorpions were designed for an outboard. I only know of one on here that runs well as a jet and thats madskillz boat, maybe he could fill you in regarding this type of hull.
What about Tikis?
 

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this may be a better asked question in the outboard section do to the fact that scorpions were designed for an outboard. I only know of one on here that runs well as a jet and thats madskillz boat, maybe he could fill you in regarding this type of hull.
I read what the court had to say, not sure I understood all the arguments involved in the patent suit over the hulls tech of the 40's and early 50's at the upper speed range of 70 to 75 mph, was it the bottom of the boat or a combo of the deck areo giving lift.
What I have learned over the years is set up is very important
You can make changes that really help your boat do its thing
The biggest problem that boats have is sitting on a shitty trailer and this can warp the running surfaces causing hooks and other undesirable waves and lumps
Blueprinting the running surfaces is just the first part of the process, finding the best c.g. balance point,for the HP your running,you can move the motor,fuel tanks, batteries, go center steer to achieve the best ride for a given hull

Our team flipped over our 19 Cougar hull last summer over and added a little more to the center pod about 3/8" it was good for a 7% gain in speed, but the real performance gains was the fact was we didn't have to trim it going into a hair pin corner from full speed and it only took two very light taps on trim switch to go from locked in to a drift or floating the boat. It nice to have your boat a click away from exactly what you want it to do,

On very fast boats like a STV hull, a outboard can run into the 140's they make there deck to increase down force as the speed comes up to help prevent blow overs

There are some very smart people on these boards that have spent many a hour dialing in set ups. The main reason you lose to someone else is they worked harder and smarter than you did :))THumbsUp You might get lucky and they will impart some of there hard won knowledge of what works
 

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So if I read that right, air packing is like a southwind that exhausts the air out the sides and transom.
Air passing is like a hydro where the boat rides on a pocket and air flows freely.
Is that correct?
From what i get a tunnel will have a place for air to escape at the transom and that area runs to the front of the boat. The air moving through the tunnel lifts the bow and as speed increases so does lift to a point where only the last few feet of the boat are wet.

A hydro is backwards. The sponsons are on top of the water, the air that passes between them blows out of the sides at low speeds. As mph increases so does lift. My deal only makes 500 hp. At about 65
the stern is still in the water. About 80 it's on top, easy to tell, it rides much smoother. Been past 100 and still a little wet. Hydro runs a cleaver prop. It is intended to lift the stern completely out of the water until only the bottom half of the prop is in the water.

With enough hp a hydro will 'blow the tail' at very low speed. More blades = more lift. I redid the bottom on mine..I think most hydro's are essentially flat on the bottom, mine is slightly concave and i believe it is intended to hold a little air under the boat. Some hydro's run air traps to help hold the air. I have a set for mine.

A hydro rides like and old 2 shock dirt bike, 25 miles hurts big time...Tunnel bottom rides like a Cadillac...They also need more power than a hydro....very few boats will run 100 with a $1500 motor
 
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