https://throt-l.com/autos/surf-turf-tug-of-war-test-pits-a-kenworth-tow-truck-vs-a-900hp-tug-boat/

This is silly but I enjoyed the physics of it. Mike

Cool!

My dad having operated a tractor when he was a kid was all about knowing when the angle of the tow rope was hurting or helping the effort. You always want the angle to load your traction wheels.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

The F in physics is for Fun

Tug turned sideways and the battle was lost...

Hi William. I have no doubt that you know of what you speak but would you mind elaborating a bit on why turning sideways was fatal for the boat?

I thought he might tip the truck over doing that.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

When the boat turned sideways it's as if a car turned sideways- imagine if the tow truck was 90 degrees turned- could the tug pull it in the water? Of course. If it was 80 degrees sideways? Obviously still yes but not quite as easy. Every drop in the angle from a right angle (70 < 60 < 50, etc) gives more power to the pull. The closer to a straight pull for either the truck or the boat results in more pulling power applied on the tow line (100% pull). Note that when the battle started the tug was winning- but then it started pulling at an angle- which lessened it's applied pulling power (something less than 100% pull)- and it was over.

Thanks William! Wonder if there was a current turning it?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

No current; least it did not look like any- water is "slippery" and it can be quite difficult to keep the boat straight in line with the tow line. Imagine pushing a long straight piece of lumber (a one by ten) on a slick floor and trying to keep it going straight ahead; if it starts to go sideways then it becomes kinda goofy and difficult to get back in line. Same principle.

Thanks! The rear push thing is a lot different than the rear wheels push and front wheels steer, isn't it?

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

Side torque thrust of the propeller while not moving could not be corrected by the tugs rudder. So the rear end pivoted around slowly.

If the tow cable had been secured to the end of the tug it may have gone better. This would depend on the upward pulling force of the tow truck though. The tugs deep prop may have allowed this but there may not have been a strong enough point aft on the tug to use.

I think that the angle of the tug would hurt the truck (make it lean to the left, lifting the right side) but as far as the tug is concerned the angle doesn't make any difference (it will pull just as hard regardless of which way it is headed).
Also the vertical angle of the cable doesn't effect the tug but does help the truck.
So what is the difference? Did you notice that the truck wheels were sliding when the tug was pulling the truck? Did you notice that the truck began spinning the tires, and at that time began pulling the tug. Have you ever noticed that at drag races, the cars do a burnout just before each run. That is to heat up the rubber so it will be softer and get more traction. The truck did a burnout and got more traction and then there was no stopping it.

PaulM

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84 500 SEL (307,xxx miles)

Think of it this way: the tug and truck are 90 degrees from the center line- the right angle of the most pull which would be straight against the opposite pull. If both the tug and the truck are facing the same way- it's not a "tug of war" anymore since both are pulling the same way. That would be described as 180 degrees "vs" 180 degrees. A tug of war is 0 degrees vs 180 degrees with a center line in the middle which is the right angle which each end is pulling 90 degrees from. If one end is less (say 45 degrees) than 90 degrees from the right angle then it's direct pull away from the center line vs a pull 45 degrees from the center line. The 90 degree pull wins every time; in fact if all else is equal then what ever end is less than 90 degrees from the right angle (aka the center line) loses. The tug twisted and was pulling at perhaps 75-80 degrees from the centerline and thus lost.

If you look closely at the time from 2:00 to 2:20 you will see that the tug was moving around but at the last, the tug was straight most of the time and the truck was pulling the tug backwards.
I think this was an "apples to oranges" advertising stunt. The truck had 500 hp but in a case like this it is the torque that pulls the load. The truck maybe had around 2000 ft lbs of torque going into possibly a 13 speed transmission. In first gear the torque to the drive shaft would be unreal. I do know if you are starting off pulling a load and forget to release the air brakes, you WILL twist the driveshaft into pieces.
The tug with 900 hp may have more or less torque than the truck. I have no idea. But the tug can't get the traction that the truck has. The tug was designed for a different type of pulling.

PaulM

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84 500 SEL (307,xxx miles)

Some tug boats have a Voith Schneider drive that lets them pull with equal force in any of the 360 degrees. I'd like to see one of these in action.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

^^Thanks for the reference. Never heard of it before...

https://www.youtube.com/watch?v=zmsT-_QdMEc

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Toyota is a leader only because their drivers block everyone behind them. Oh what a feeling.