Real Time Thrust Tests with Complete Boats

Does anybody know how the "Perceptions of Increases" was calculated? It says that a change of 10 decibels is perceived as twice as loud, but other sources on the web say that an increase of 10 decibels is 10 times louder and an increase of 20 decibels is 100 times louder. I am trying to understand the differences. Thanks.
 
When calculating decibels, every 3 DB is double the power in the signal.

If you don't normally work with Decibels its confusing as hell, so I will try to find a better logical technical writeup on line. I'll cut it in here after I find it for ya. I am assuming you are specifically asking about dB SPL (sound pressure level) so thats what I will look for.

Excellent dB SPL writeup:

http://trace.wisc.edu/docs/2004-About-dB/

Perception of Loudness (20dB = 4x)

Interestingly, our perception of loudness is not the same as sound pressure level. Although the actual formulae
is somewhat complex, as a rough rule of thumb, an increase of 10db SPL is perceived to be approximately twice as loud.

Thus a 20 Db gain would seem to be about 4 times as loud.
And a 40 Db gain would seem to be about 16 times as loud.

I think this perception is actually what the question was. Keep in mind the 10 dB is a rule of thumb not an actually calculated level for perception to be twice as loud.
 
Got it Scotty. For some reason I had 1 decibel in my head, but it's 10. I also understand that is just a guideline. So the original .8 decibels I questioned isn't that much of a difference.
 
Here's how I've been taught:

Every increase of 3 dB represents a doubling of sound intensity, or acoustic power.

So, I guess that a 1 DB increase would be about 1/3 louder. I don't know...

It's still pretty significant.

Duane
 
Thanks plumcrazy and whitebear. I definitely learned something.

Yobee,

You need to stop asking such difficult questions. It makes me think too hard. :lol:
 
CarMotorBarge said:
Thanks plumcrazy and whitebear. I definitely learned something.

Yobee,

You need to stop asking such difficult questions. It makes me think too hard. :lol:
Click to expand...

Why do aircraft boats run so much better than carbarges? hehe
Thanks for the ride saturday, hadnt been out in a while lol
 
intel, company, and fish begin to stink after three days. I hope the exact numbers are posted sooner than later. all the boats ran between 98 and a little over 102 decibles at full throttle. The difference in the wood prop and the q carbon fiber was a .8 . A difference you could not determine with the human ear. at least not with the ones I am using. once posted the information should clear things up I am working from memory i dont have the numbers infront of me. Some times all three brain cells dont hold hands.
 
Sorry for the delays! We are trying to test, play a little and most of us have jobs that take way too much time! I am going to provide some initial thrust numbers in this post. There will be much more detail to follow inclusive of spreadsheets and graphs. Big Casino is working on his fancy reports and making final adjustments as we speak.

The results I am going to share now are just "test as you drive" numbers with no effort to get the max thrust number. We did have some boat owners modify their motor or prop to improve thrust numbers after the initial pull.

I will provide some basic info about each boat and you can go to the picture gallery for a picture of each boat. (The pics were posted by Big Casino).

After some of the boats were “tweaked” the order changed slightly. Some owners chose not to make any changes

Boat Thrust
C 1423
B 1365
G 1319
A 1310
D 1309
E 1077
I 876
H 841
F 740


Test Boat A
15' Scorpion
383 SBC
2:68 Rotator
526 HP @ 6000 RPM per Dyno sheet
3 blade R
4" SS cage
S by S driver, triple up front
Air ride

Test Boat B
15' Scorpion
Modified 351W (bored and stroked)
Approx 12.5:1 compression
HP: Unknown but 500+
2:67 belt drive
3 blade R
4" plus SS rigging
S by S driver, triple up front
Brand new boat not quite finished

Test Boat C
16' Scorpion
496 BBC (Voss Racing)
547 HP @ 5100 RPM per Dyno Sheet
Staggered 8 blade saber
1.91: 1 Belt Drive
4" SS Cage
Single driver, double up front

Test Boat D
16' Jimmy White
427 SBC by MAS
602 HP @ 6000 RPM per Dyno Sheet
4 Blade R
2:68 Stinger
4" SS Cage
S by S driver, triple up front

Test Boat E
12.5' Hamant Ultralight
EFI, LS1
Horsepower unknown: Approx 500
3 Blade R
2:68 Stinger
2 x 4 SS Cage
S by S driver, no front seats



Test Boat F
14' "Jimmy White"
Motor: 220 GPU
HP: Unknown
Prop: 74" Water Walker - 2 Blade
2 x 4" SS Cage
S by S driver, Triple up front

Test Boat G
16' Jimmy White
6.2 L Waterthunder
500 HP (no Dyno)
3 Blade R
2:38 Stinger
4" SS Cage
S by S driver, Triple up front
Air Ride

Test Boat H
15' Marty Bray
0-520 gitsu Conversion
Estimated @ 300 hp
74" 2 Blade "Q"
4" SS Cage
S by S Driver, removable front seat pkg.

Test Boat I
RiverMaster 1450
0-540 parrallel valve
HP Unknown
72" NGH - 3 Blade
4x4" SS Cage
S by S driver, double up front
 
interesting the 3 blade r made more thrust that the 4 blade r.and only 10lbs of thrust between differences.
 
Boat G what was the prop set at? That is closest to my set up. Thanks,Jim and bet this was fun to do all this testing.
 
Man this is some interesting stuff..I can see where some 2.68 guys might be scratching there heads....Really good info and thank you for sharing it.......
 
C1gator said:
Man this is some interesting stuff..I can see where some 2.68 guys might be scratching there heads....Really good info and thank you for sharing it.......
Click to expand...

You aint kidding, It really suprised me. The Water Thunder with the 2.38 showed us all up. But we will be testing that same motor with a 2.68 so we will know the real differance. Wait till you see the cruise numbers with the 2.38 and also the 1.9 belt.

Come on Dave you know your motors better than anybody take a guess what the differance will be between the 2.38 and 2.68. I must admit I hope the 2.68 does a little better.
 
I cant make heads nor tails of this. I don't see one test boat with the RPM the thrust was measured at. Without that info the thrust produced is mostly a useless number for any comparison. I'm just lost I guess.

I keep trying to see what RPM the props are turning for the thrust measured. Maybe that part will show on the graphs and charts. If so, then I am jumping the gun right now.
 
Its pretty cool yall sat down and did this, lots of work for sure. Itll be cool to sit back and read all the info when ya get it ready, no rush on my part. Im just offended that big casino let a straight valve 540 out push him... :oops: :lol:
 
So all the small blocks had 2.68's accept the WaterThunder which had a 2.38. I will say when propped and pitched correctly the 2.68 makes more thrust. There are several issues that effect all this and we have way to much RnD time an money to give it up. But we must be doing something right if a 4 year old 500HP motor with a 2.38 ratio out trusted the other small blocks that had 600HP plus dyno sheets and 2.68 ratios. I wish they would have done one of our 600HP's with a 2.68 I know for a fact our 600HP with a 2.68 on average makes around 400lb's more of thrust then a 500HP with a 2.38.
 
Roxy7430 said:
Sorry for the delays! We are trying to test, play a little and most of us have jobs that take way too much time! I am going to provide some initial thrust numbers in this post. There will be much more detail to follow inclusive of spreadsheets and graphs. Big Casino is working on his fancy reports and making final adjustments as we speak.

The results I am going to share now are just "test as you drive" numbers with no effort to get the max thrust number. We did have some boat owners modify their motor or prop to improve thrust numbers after the initial pull.

I will provide some basic info about each boat and you can go to the picture gallery for a picture of each boat. (The pics were posted by Big Casino).

After some of the boats were “tweaked” the order changed slightly. Some owners chose not to make any changes

Boat Thrust
C 1423
B 1365
G 1319
A 1310
D 1309
E 1077
I 876
H 841
F 740


Test Boat A
15' Scorpion
383 SBC
2:68 Rotator
526 HP @ 6000 RPM per Dyno sheet
3 blade R
4" SS cage
S by S driver, triple up front
Air ride

Test Boat B
15' Scorpion
Modified 351W (bored and stroked)
Approx 12.5:1 compression
HP: Unknown but 500+
2:67 belt drive
3 blade R
4" plus SS rigging
S by S driver, triple up front
Brand new boat not quite finished

Test Boat C
16' Scorpion
496 BBC (Voss Racing)
547 HP @ 5100 RPM per Dyno Sheet
Staggered 8 blade saber
1.91: 1 Belt Drive
4" SS Cage
Single driver, double up front

Test Boat D
16' Jimmy White
427 SBC by MAS
602 HP @ 6000 RPM per Dyno Sheet
4 Blade R
2:68 Stinger
4" SS Cage
S by S driver, triple up front

Test Boat E
12.5' Hamant Ultralight
EFI, LS1
Horsepower unknown: Approx 500
3 Blade R
2:68 Stinger
2 x 4 SS Cage
S by S driver, no front seats



Test Boat F
14' "Jimmy White"
Motor: 220 GPU
HP: Unknown
Prop: 74" Water Walker - 2 Blade
2 x 4" SS Cage
S by S driver, Triple up front

Test Boat G
16' Jimmy White
6.2 L Waterthunder
500 HP (no Dyno)
3 Blade R
2:38 Stinger
4" SS Cage
S by S driver, Triple up front
Air Ride

Test Boat H
15' Marty Bray
0-520 gitsu Conversion
Estimated @ 300 hp
74" 2 Blade "Q"
4" SS Cage
S by S Driver, removable front seat pkg.

Test Boat I
RiverMaster 1450
0-540 parrallel valve
HP Unknown
72" NGH - 3 Blade
4x4" SS Cage
S by S driver, double up front
Click to expand...
Is it possible to post what the engine RPM's were at peak thrust?
 
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