Magnetic Fishing -- weird question, I know

[RockHoundTX]

21 hours ago, joeyancho said:

Please excuse my ignorance but  anything that would stick to a magnet  would be made of iron.  Wouldn't it be too rusty after being in salt water for a period of time?   I do see that you would be likely to bring up anything of value.  But I am willing to be wrong.  

You would be amazed at what you can find. At any major saltwater fishing pier, I bet their are a dozen fishing knives and pliers lost every week. These tend to be made of stainless steel so survive in pretty good shape in saltwater for quite a while.

 

In freshwater lakes, pretty common to find whole fishing poles (rod and reels) especially around boat docks. If they haven't been in the water for more than a month or so, just rinse them off and you are good to go.     

[RockHoundTX]

On 10/14/2022 at 10:15 PM, Airbear232 said:

Sounds really interesting, but a few Q’s from curiosity.  What strength magnet does he use.  What’s the test of the line?  Does he “lose” a lot of magnets?  I mean if you contact rebar in the water, you most probably lose your magnet.  Just curious.   Sounds fun. 

Magnets come in varying strengths. You will see claims of anywhere from 100 pounds up to 1000+ pounds (with 300-500 pound magnets being the most common "beginner" magnets). The magnet itself is maybe 3 inches in diameter and 3-4 pounds. 

 

These "strengths" are generally measured as how heavy a perfectly flat metal plate can be lifted (and most manufactures then double that since the magnet technically has 2 sides even though only 1 side is usable). In the real world, almost nothing is a "flat sheet of metal" so a 300 pound magnet can typically bring something up that is maybe 20-30 pounds. If a 300 pound magnet sticks to a piece of rebar, it can be "unstuck" fairly easily with a little force (it will most likely just slide off the end of the rebar). However, if you stick the magnet to the flat metal wall of a cruiseship, it is going to be HARD to get it off (practically impossible to pull it straight off. You have to leverage it to get one corner up and then it will come off pretty easy.).

 

The "line" is actually a very heavy 8mm-10mm nylon rope (typically 50-75 feet long) with a tensile strength of 1000-2000 pounds. When magnet fishing, the biggest problem is not getting the magnet stuck to something, it is getting it hung on an underwater tree-root, rock, etc. It is pretty common (but potentially dangerous) to have to tie the rope to a vehicle (or winch system) to get it unstuck. It really sucks to loose a $100-$200 magnet 😕 Most magnets are lost because folks forget to put red locktite on the screw-in eye-let or tie a bad knot in the rope.    

 

There are a ton of great videos on YouTube for those that are interested. 

 

[Airbear232]

7 hours ago, RockHoundTX said:

Magnets come in varying strengths. You will see claims of anywhere from 100 pounds up to 1000+ pounds (with 300-500 pound magnets being the most common "beginner" magnets). The magnet itself is maybe 3 inches in diameter and 3-4 pounds. 

 

These "strengths" are generally measured as how heavy a perfectly flat metal plate can be lifted (and most manufactures then double that since the magnet technically has 2 sides even though only 1 side is usable). In the real world, almost nothing is a "flat sheet of metal" so a 300 pound magnet can typically bring something up that is maybe 20-30 pounds. If a 300 pound magnet sticks to a piece of rebar, it can be "unstuck" fairly easily with a little force (it will most likely just slide off the end of the rebar). However, if you stick the magnet to the flat metal wall of a cruiseship, it is going to be HARD to get it off (practically impossible to pull it straight off. You have to leverage it to get one corner up and then it will come off pretty easy.).

 

The "line" is actually a very heavy 8mm-10mm nylon rope (typically 50-75 feet long) with a tensile strength of 1000-2000 pounds. When magnet fishing, the biggest problem is not getting the magnet stuck to something, it is getting it hung on an underwater tree-root, rock, etc. It is pretty common (but potentially dangerous) to have to tie the rope to a vehicle (or winch system) to get it unstuck. It really sucks to loose a $100-$200 magnet 😕 Most magnets are lost because folks forget to put red locktite on the screw-in eye-let or tie a bad knot in the rope.    

 

There are a ton of great videos on YouTube for those that are interested. 

 

@RockHoundTXthank you, great explanation, something that I’ll have to try!

[Cyndi874]

Wouldn't this completely destroy any and all TSA xray/screening machines during security checks, which you'd probably then have to pay for? And what happens if someone with a metal pin/implant or pacemaker gets near it, given that many elderly people travel on cruises?

 

It seems to me like it would get you in a tremendous amount of trouble if not get you sued or be liable for any harm or damage it would cause to vital equipment and other passengers.

Edited October 16, 2022 by Cyndi874

[Mum2Mercury]

10 hours ago, PolicromaSol said:

 

I have this mental image of a guy with a fishing pole catching random metal items right out of peoples' hands from the balcony below...

 

If this becomes a big thing I'm sticking to cabins with windows! 🤣

That's one way to get a cheap beer!

[gmerick]

I carry two 100lb pull magnets with me on every cruise.  They have a mechanical knob that is turned to activate the magnet (not electric).  They stick to nothing when "off", and hold my dive gear to dry on the balcony when "on".  They only weigh several ounces, so there's no issues with packing or TSA.  BTW, fishing for stainless steel objects doesn't work -- most stainless is non-magnetic.  My magnets don't stick to my dive knife.  Likewise my titanium line cutter.  

[gmerick]

• Max Breakaway Force: 152.8 lbs / 69.3 kg
• Max Shear Force: 35.3 lbs / 16.0 kg
• Full Saturation Thickness: 0.197 in / 5.0 mm
• Product Weight: 0.69 lbs / 0.31 kg
• Dimensions: 1.9 x 1.2 x 2.5 in / 48 x 31.2 x 64.25 mm
• Magnetic Pole Footprint: 48 mm x 31.2 mm

[Junkhouse]

Too bad coins aren’t made from magnetic material.

Edited October 19, 2022 by Junkhouse