OT: 4th July small town craziness

[Keith A]

John Mellencamp's "Small Town" song comes to mind when I saw this picture from the town where I went to high school. I didn't actually see this myself, but was there this weekend. Apparently, this was in a very deep part of the river and not only was this truck was floating, but it was towing a raft :eek:

[AngryScientist]

that's got to be on a sandbar, or a photoshopped image.

first off, there is no way a set of big tires like that are going to float a full sized truck, and the real telltale is that the front end is not any lower than the rear.

funny picture though!

[F150]

"Natural selection" comes to mind. Hope they made it home safely. One slow speed pass by a decent sized cabin cruiser and that Ford would be on the bottom.

[Keith A]

that's got to be on a sandbar, or a photoshopped image.

first off, there is no way a set of big tires like that are going to float a full sized truck, and the real telltale is that the front end is not any lower than the rear.

funny picture though!Nick -- No sandbar in the middle of this river, it's easily 20 to 40 feet deep there. I've had multiple witnesses who saw and took pictures of this.

[Dead Man]

Seems like even if the tires had enough buoyancy, the thing would be at extreme risk of capsizing

Seems like, to this layman anyway

[Keith A]

Seems like even if the tires had enough buoyancy, the thing would be at extreme risk of capsizing

Seems like, to this layman anywayThat's exactly what I thought.

Nick -- Here's a little information on the St. Johns river...
Between Palatka and Jacksonville, that widens further to between 1 and 3 miles (1.6 and 4.8 km). This portion of the river is the most navigable and shipping is its primary use. The Army Corps of Engineers maintains shipping channels at least 12 feet (3.7 m) deep and 100 feet (30 m) wide. North of Palatka, the channels are expanded to 40 feet (12 m) deep and between 400 and 900 feet (120 and 270 m) wide

[Mark McM]

that's got to be on a sandbar, or a photoshopped image.

first off, there is no way a set of big tires like that are going to float a full sized truck, and the real telltale is that the front end is not any lower than the rear.

funny picture though!

Hmmm... Not so sure ...

Let's throw out a few numbers. Archimedes tells us that a floating object weighs the same amount as the water it displaces. Since the tires are almost completely underwater, the truck must weigh a little less than the water the same volume as the tires. Let's start with the volume of the tires:

Tires are basically a toroid. I can't tell the size of the tires exactly, but let's look at a tire with width of width of 40 cm (16") and an outer diameter of 140 cm (55"). This gives the tires a minor radius "r" of 20 cm and a major radius "R" of 100 cm. The formula for the volume of a toroid is:

V = 2 x pi*2 x R x r*2 = 2 * (3.14159)*2 x ( 100 cm ) x ( 20 cm )*2 = 789,568 cm*3.

A cubic centimeter of fresh water weighs 1 gram, so the water displaced by one tire is 789,568 g = 789.568 kg = 1741 lb. All 4 tires combined displace 6964 lb.

It seems possible that the truck weighs less than 7000 lb., so it seems feasible that the truck could float.

[AngryScientist]

Hmmm... Not so sure ...

Let's throw out a few numbers. Archimedes tells us that a floating object weighs the same amount as the water it displaces. Since the tires are almost completely underwater, the truck must weigh a little less than the water the same volume as the tires. Let's start with the volume of the tires:

Tires are basically a toroid. I can't tell the size of the tires exactly, but let's look at a tire with width of width of 40 cm (16") and an outer diameter of 140 cm (55"). This gives the tires a minor radius "r" of 20 cm and a major radius "R" of 100 cm. The formula for the volume of a toroid is:

V = 2 x pi*2 x R x r*2 = 2 * (3.14159)*2 x ( 100 cm ) x ( 20 cm )*2 = 789,568 cm*3.

A cubic centimeter of fresh water weighs 1 gram, so the water displaced by one tire is 789,568 g = 789.568 kg = 1741 lb. All 4 tires combined displace 6964 lb.

It seems possible that the truck weighs less than 7000 lb., so it seems feasible that the truck could float.

i was just about to do the math myself, what you have seems feasible, however, look at the second picture - it is unexplainable that the rear end of the truck, if anything looks a little lower. the rear of a pickup weighs so much less than the front end it's near impossible that the truck would "float" like that...

[Geeheeb]

here in michigan we put weight in the back of our trucks so they don't slide around in the winter, or i guess the water...

[AngryScientist]

here in michigan we put weight in the back of our trucks so they don't slide around in the winter, or i guess the water...

yea, could be loaded with beer i guess!

[Dead Man]

Hmmm... Not so sure ...

Let's throw out a few numbers. Archimedes tells us that a floating object weighs the same amount as the water it displaces. Since the tires are almost completely underwater, the truck must weigh a little less than the water the same volume as the tires. Let's start with the volume of the tires:

Tires are basically a toroid. I can't tell the size of the tires exactly, but let's look at a tire with width of width of 40 cm (16") and an outer diameter of 140 cm (55"). This gives the tires a minor radius "r" of 20 cm and a major radius "R" of 100 cm. The formula for the volume of a toroid is:

V = 2 x pi*2 x R x r*2 = 2 * (3.14159)*2 x ( 100 cm ) x ( 20 cm )*2 = 789,568 cm*3.

A cubic centimeter of fresh water weighs 1 gram, so the water displaced by one tire is 789,568 g = 789.568 kg = 1741 lb. All 4 tires combined displace 6964 lb.

It seems possible that the truck weighs less than 7000 lb., so it seems feasible that the truck could float.

float, sure.. but with almost ALL of the weight above the waterline, how do you keep it upright?

[Mark McM]

float, sure.. but with almost ALL of the weight above the waterline, how do you keep it upright?

The flotation is basically all from the tires, which are spread apart. These can act as pontoons. On most pontoon boats, the majority of the weight is above the waterline, and yet they are quite stable, due to the spread of the pontoons.

http://www.go2chl.com/images/pontoon.jpg

Catamarans also have their weight above the water line, but are quite stable due to the spread between the twin hulls:

http://catamaranguru.com/images/articles/CharterManagement/luxury_catamaran_charter.jpg


I don't think the truck would be as stable as either of the above, but the spread between the tires/flotation does add some stability.

[ORMojo]

Nvrmnd

[cachagua]

Y'all know what a redneck's last words is?

"Hey fellers, watch this!"

[astrov]

it has a boat registration visible on the front-left quarter panel, if that provides any further grounds for speculation. :p

[Dead Man]

The flotation is basically all from the tires, which are spread apart. These can act as pontoons. On most pontoon boats, the majority of the weight is above the waterline, and yet they are quite stable, due to the spread of the pontoons.

http://www.go2chl.com/images/pontoon.jpg

Catamarans also have their weight above the water line, but are quite stable due to the spread between the twin hulls:

http://catamaranguru.com/images/articles/CharterManagement/luxury_catamaran_charter.jpg


I don't think the truck would be as stable as either of the above, but the spread between the tires/flotation does add some stability.

The pontoons on those also sit above the water line... you'd need a hell of a lot of torque to submerge them. Maybe the displacement is so low, you couldn't even - to capsize, you'd have to actually lift one end of the vessel and tip the whole thing up. But with tge truck, the "pontoons" are already submerged and displacing a couple tons of water... so their tendency would be to want to flip.

I have no idea what the physical laws are involved here, I just know the more you push something that floats under water, the more it wants to pop back up - and there's no way in hell that truck is just staying upright all on it's own without any additional stabilizing modification. Thing must have a weighted keel/skeg or something

[AngryScientist]

quite stable, due to the spread of the pontoons.



it's more than the spread, it's the excess buoyancy that resists the rollover force. with all four tires of the truck essentially already submerged, there is no (or little) excess buoyancy, which would make it quite unstable to rollover forces.

i dont know exactly what was going on over there in florida, but there is more to the pictures than meets the eye.

[stien]

Those tires are enormous if you look closely. Not surprised it floats and "paddles".

[Keith A]

Not sure if these will be visible or not, but here are the Facebook links to where the pictures are posted. There is some discussion on the truck there...

https://www.facebook.com/photo.php?fbid=10101467589101805&set=a.775296068635.2240176.33409920&type=3&theater
https://www.facebook.com/photo.php?fbid=1215350838498662&set=a.110081692358921.9059.100000712722388&type=3&theater

[Keith A]

Here's a more revealing picture of what's going on...

[Keith A]

And here's a video of the truck being launched (again it's on Facebook)...

https://www.facebook.com/darrin.anderson.3152/videos/1238884039487674/

[christian]

44" duals on both axles? Yeah, it'll float, easy. How stable? Good primary stability, extremely poor secondary stability.

[AngryScientist]

yea, that truck has a lot more rubber than i initially gave it credit for!

[Dead Man]

Indeed.. double dually... that's how it's (she's?) staying upright

Pretty cool. Not street legal, though... so cool, but not AS cool :beer:

[Ken Robb]

There is a secret waterproof compartment under the bed normally used to smuggle limes or other stuff from Mexico.