Main crash concern transporting Scuba tanks?

[CuzzA]

Oh, paint. As a kid on the Autobahn I witnessed a station wagon rear ending the vehicle in front. We (my grandma driving) just barely managed to stop in time. Out came two nuns in blavk nun-dresses, wingy hats and all just DRENCHED in white paint...
... shaken up, dripping white, looking quite funny despite the situation, otherwise OK...

But heavy object that don't disintegrate are of concern to any occupant... and anything on the roof is of concern to anyone in front of you...

I couldn't even imagining that happening to me. You would just have to laugh, unless it's oil based.

 

[CuzzA]

But heavy object that don't disintegrate are of concern to any occupant... and anything on the roof is of concern to anyone in front of you...

Not only the roof, but the bed of trucks and trailers....

We were driving to Orlando once on Interstate 4 doing about 70 mph when a pitch fork came off a trailer and went right into the grill.

Another time we had a tire peel off the wheel of a semi truck in front of us and strike our windshield.

I think this all confirms it's safer underwater than on the road.

 

[wheeledgoat]

Every video I've seen of purposefully shearing a tank valve to enjoy the carnage makes a point of giving the tank a good run to build up speed before plowing into a wall or other object to be destroyed. Without trying it myself, I'm pretty sure lacking that space (e.g. resting against the truck bed or rear seats) and robbed of the ability to build inertia, the damage will be a lot less spectacular. I imagine it'll just be a lot of hissing, which you may or may not notice depending on your state after whatever event caused the tank to be damaged.

Now for a related but unconstructive tangent:
We took off for the far side of Lake Michigan to do a shore dive. Hadn't been there before but planned as best I could. Turns out my intended point of beach entry was private property. Onto Plan B, which was to access via sand dunes. Outfitted my Forester with flag and offroad sticker and had an unexpectedly great time bombing around the dunes on my way to the beach! I had never done that before. We took the long way around going up and down hills. At the bottom of one particularly steep hill were what I will call moguls - many [significant] bumps in a row. Didn't notice them until I was about 2/3 down the hill and going too fast to stop. I was having so much fun I had forgotten about the pressurized cylinders in the back.... until I heard them bouncing and clanging around. As we were getting jostled around my eyes widened and I glanced in the rear view mirror. Not sure what I was hoping to see. I had them well nestled in the back, with pool noodles between them; a setup that had worked well many times before. Turns out it didn't hold once my car was airborne. We survived, but that was the last time I transported tanks without actively strapping them DOWN...

 

[kelemvor]

Every video I've seen of purposefully shearing a tank valve to enjoy the carnage makes a point of giving the tank a good run to build up speed before plowing into a wall or other object to be destroyed. Without trying it myself, I'm pretty sure lacking that space (e.g. resting against the truck bed or rear seats) and robbed of the ability to build inertia, the damage will be a lot less spectacular. I imagine it'll just be a lot of hissing, which you may or may not notice depending on your state after whatever event caused the tank to be damaged.

A good point, and one I hadn't considered. Wish I had a tank I was willing to destroy to make a youtube video debunking the others. It would get a hundred hits! Maybe even two hundred.

 

[Schwob]

but that was the last time I transported tanks without actively strapping them DOWN...

Yep. In my mind a necessity... but I grew up driving (young and dumb) in ways that e.g. made the concept of a cup holder an entirely foreign one.

 

[3arl J0n35]

I don't put much credibility in the "thru the cinder block wall" test. You can hit a cinder block with a rubber mallet and knock a hole in it. A cinder black in not much more than glued together dust.

My concern in a shear would be the VALVE, not so much the cylinder. Having less mass than a cylinder, the valve would become the more dangerous projectile. I once watched a guy in the shop who removed his tank valve with some air left in the tank. Once the last couple of threads let go the valve went straight up like a rocket and thru the ceiling to the second floor of the building.

I've also seen photos of a guy here in NC who removed his tank valve for a VIP while it had some air left in it. He was standing over the valve when he removed it and the valve struck his chin and went up his face basically removing his lips and nose and eye sockets as it passed, leaving it a bloody pulp of a mess. It took several surgeries just to make him look grotesque. That's why I never stand in front of a valve when removing it for a VIP.

The guy who's valve went thru the ceiling was replacing it. He had opened the valve to drain the tank and after 10 minutes or so it stopped "hissing" so he thought it was empty. What actually happened (we later found out) was the rapid de-pressurization froze the valve up and some ice was blocking the air channel. There was enough air left inside to be dangerous but not enough to blow the ice out.

I would suspect that a sheared valve, what with the way they make pickups nowadays with thin-as-paper sheet metal, would possibly go right thru a tailgate or quarter panel and keep right on going. That might suck for the guy in the vehicle behind you and possibly open you up to liability/negligence legal problems.

 

[DerekR]

I just concern myself with driving defensively. If the tanks have a problem, I have much bigger things to worry about!

 

[Seaweed Doc]

I've got a pickup (with canopy) I only drive for diving and snow, and my bigger concern is the tank getting knocked out the back of the vehicle. If it falls out, I'd rather have it fall base first rather than valve first. That is, the base clears the tailgate before the valve. I've always put tanks in valve first.

I've gotten to thinking about the valve shooting forward, though. I wouldn't worry if it hit the double-wall (truck bed, cab wall) and then a seat back. It doesn't that much mass, and has a lot of steel (old truck) and such to penetrate. I wonder if it hit the glass windows (canopy and cab), though, what damage might happen?

Might start laying tanks sideways.

Tanks aside, I also have molded lead weights that could start flying around the back of the truck.Maybe I'll strap tanks down and put the weights under them?

 

[EireDiver606]

I think even if you want to, it would be hard to shear off the valve. They’re fairly indestructible to a certain degree.

 

[smorneau]

Both scenarios are plausible. I would lean toward option A being the most likely to cause serious injury or death. Especially rolling over an SUV and cylinders flying throughout the cabin.

Of course the odds are low, but picking up some ratchet straps and tie down the cylinders would solve both potential issues. Admittedly, I just lay them in the back of my truck unsecured. I should probably change that practice.

Plausible!