When would a wooden barrel implode? (sinking under water)

[James3355]

Two scenarios for you...
A) A wooden barrel, say 50 litres, is sealed with just air inside.
B) A wooden barrel, also 50 litres, is sealed but is completely full with water.

If you weighted both of them and sunk them in the ocean, at what depth would they implode from the pressure at depth? Is the water-filled barrel going to survive longer because it is less compressible?

 

[Bystander]

water-filled barrel going to survive longer because it is less compressible?

Yes. Next --- what wood? What stave thickness and radius? What length to diameter?

 

[sophiecentaur]

Water is very hard to compress. As you take the water-filled barrel deeper and deeper, the sides will 'give' a bit but the internal pressure will always be high enough (until you are sooo deep that water ceases to behave like water on Earth (I suspect)) but the sides would not actually fracture. (The displacement would be so small)
Otoh, if the barrel were filled with air, the water pressure on the weakest sections of the barrel would soon push it in because the internal pressure would follow that of the gas laws and, basically, hardly change at all by the time the barrel was crushed. At what depth? No idea but I suspect a very few atmospheres of pressure would do it (thinking in terms of the early Atmospheric Engines which had a problem even withstanding one atmosphere.

 

[jackwhirl]

Yes. Next --- what wood? What stave thickness and radius? What length to diameter?

I've not crunched any numbers, even on a napkin, but I'd bet the ends would implode before the walls. I'm thinking the staves would tend to behave as an arch and support each other.

 

[phinds]

I've not crunched any numbers, even on a napkin, but I'd bet the ends would implode before the walls. I'm thinking the staves would tend to behave as an arch and support each other.

Yes, I think that is what would happen, exactly as you say.

 

[sophiecentaur]

I've not crunched any numbers, even on a napkin, but I'd bet the ends would implode before the walls. I'm thinking the staves would tend to behave as an arch and support each other.

Yes. I think you are right about the flat ends going first. I can't imagine the amount that the water inside would be enough to distort the wood past fracturing. But I guess the wood itself could become compressed so much as to destroy its internal structure. No use as a barrell after the experiment.