Billy.Guttery:

That is quite a piece of equipment for such a low price.

Although a knife in sand bottom might come up very easily with a 30 lb. pull magnet, if that knife fell between some weeds and the magnet pulled it up horizontally, there might be a problem. As the knife comes to the magnet, it may straddle some weeds which will put more resistance on the retrieve than if the knife were in bare sand or on a rocky surface.

If I had lost that knife, I would spend the money for that magnet and give it a try. If I sense attraction, but lose it while pulling, either something heavy is on (Barrel containing Jimmy Hoffa?), or the aforementioned interference from weeds. At that point, at least you will have a good idea where to look again with a stronger permanent magnet, or an electro-magnet using a car battery.

Bountyhunter