Would a fishing line be able to withstand 20000psi? Assuming the line is going straight down for about 12000 metres.?

Answer 1

Are you going fishing in the Mariana Trench?

Your depth number is actually deeper, so not sure where you are thinking about?

Answer 2

Look, even a bit of simple WATER can withstand pressures like this. So a piece of cake for a nylon line.
Or a bit of steel. Or carbon. Or Oil.
Most materials on earth can withstand this pressure if it is evenly distributed as it is at the bottom of the ocean.

The line would snap due to the lack of TENSILE strength. Which happened when trying to lay the trans atlantic cable.
And that was not 12000 m deep.

So consider a material with a density of 3 times that of water. 3000kg / m^3
at 12000 m long this needs a tensile strength of 10 * 12000 * 3000 = 3.6 * 10 ^ 8 N/m^2
The ultimate strength is given as 8.3 * 10 ^ 7 Pa so it is less than a quarter the necessary strength to support itself over this length.

Steel has a density of 8000 kg/m^3 and a breaking strain of 3.7 * 10^8 Pa
Due to its increased density it would need to have a strength of at least 7.2 * 10 ^ 8 Pa so it also would fail.

As you can see the crushing potential is the least of your worries at this depth.

But if somehow you could take your normal fishing line and fishing pole to this depth and survive then you would be able to fish quite normally.

Answer 3

The Challenger Deep in the Mariana Trench is the deepest known point in Earth's oceans. In 2010 the United States Center for Coastal & Ocean Mapping measured the depth of the Challenger Deep at 10,994 meters (36,070 feet) below sea level with an estimated vertical accuracy of ± 40 meters. The pressure of the water is about 18,000 psi, but the real load would be from holding up 7 freaking miles or 11 km of fishing line. That is a lot of line, like more than 100 big spools of line you would find at the fishing store.

Answer 4

Your numbers are absurd, not helped by mixing imperial and metric units. There is almost no place on earth where 12000 meters straight down is possible and at that location the force would be about 1200 atmospheres or 1200 * 14.4 psi or 17280 psi. And the pressure on the line is irrelevant because the real problem is the huge drag on 12 km of line from the water which would require a very special rig to simply pull it back up and keep it from snapping due to the rise and fall of the boat.

Answer 5

"The deepest point in the ocean is the Mariana Trench, located in the Pacific Ocean. It has a maximum depth of 10,923 metres "

Answer 6

The line will withstand the pressure, however, you'll need something that can handle the length of the line's weight (many fishing lines are near neutrally buoyant in water) + load. Drift of the vessel will also complicate things.

Answer 7

No, it would not. Not at 12 000 meters length.

Answer 8

Probably, depends on composition and conditions. The substance is a solid and will not undergo any significant compression in water from the weight (pressure) of water, unless it is some sort of plastic that has a very limited pressure maximum before it undergoes phase change ("melting" or crystallization, or decomposition). There will be issues of tensile strength and drag. 12 kilometers of line would have a very large cumulative mass and thus large weight, even with the force offset of buoyancy, and of course any movement (pulling one direction or another) would add to that.

The main issue is not the pressure associated with the depth. It is the exaggeration of the usually tiny forces that are imposed that produce the greatest risk of line failure (breakage). The weight of that length of line would exceed the "weight" limit for the line unless you have a very high weight limit (high tensile strength).

Fishing line does not have an infinite strength.

Answer 9

yes. The pressure would just compress the line.

Answer 10

It does, doesn't seem to have any effect on it either.