Video: Leeds dad and son who died on canal fishing trip are namedWhat is magnet fishing?
Magnet fishing, also known as magnetic fishing, is the act of searching in outdoor waters for magnetic objects which are available to pull with a strong neodymium magnet.
This hobby, which is a combination of environmentalism and treasure hunting, has grown rapidly in both the UK and the US over the past few years and requires almost no technical knowledge to get started.
The only equipment needed for magnet fishing is a powerful magnet with a loop or eye attached to it, strong rope, a pair of gloves and a something in which to put any metallic objects you may find.
The magnets used are strong enough to remove large debris such as discarded bicycles and car tire rims from bodies of water, but many who engage in the hobby are hoping to find rare and valuable items including historic relics and modern-day gadgets.
Magnet retrieval tools are specially designed to retrieve items that are lost at the bottom of bodies of water, with rivers, lakes and streams being typical places to magnet fish.
Canals are also a popular place to magnet fish, due to the huge number of items casually discarded in them over the past few centuries.
People who engage in the hobby may be referred to as 'magnetfishers' or 'magneteers'.
Deaths of Leeds father and son magnet fishing in canal not suspicious - policeWhat are the dangers of magnet fishing?
One of the primary dangers that magnet fishing poses is the type of magnet used. Magnets made from neodymium are amongst the strongest magnets in the world and the force at which they attract to both steel and each other can cause serious injury if necessary safety precautions are not followed.
Small magnets can slam together and shatter and any magnets larger than a penny can pose an extreme danger as these magnets are sintered.
This means that they are not a solid mass of metal or ceramic, but are rather compressed powder, hence splintering or shattering very easily, causing chunks of metal to take flight.
Steep river or canal banks and strong currents also poses the risk of drowning, whilst the items found whilst magnet fishing can also be a potential risk.
Historic relics such as ancient guns have been previously found by those taking part in this hobby and earlier this month and an unexploded World War II bomb was unearthed in Northamptonshire.
In November last year, a woman magnet fishing in Wales pulled an unexploded World War II shell from a canal, and in 2015 a young boy pulled an unexploded World War II grenade from London's Grand Union Canal, all posing risks to those involved.