Part I. Maximize Efficiency by Taking a Toe-to-Heal Stride while Metal Detecting

[LawrencetheMDer]

Metal detecting is all about efficiency: the more efficient you are the more targets you’ll find and the happy you will be in the hobby. Two of the root factors of metal detecting efficiency are the stride and the swing. In Part I, I discuss the efficiency of the stride and in Part II I discuss the swing. By maximizing the stride and maximizing the swing, the Metal Detectorist will maximize targets found.
Back story: I was hunting Melbourne Beach, Fl years ago and inspecting a 4 ft cut with my Excal II at a popular beach. I was swinging my coil up-and-down along a 4 ft vertical cut and soon came across a thin 14k gold chain and cross. As I was putting the chain and cross in my pouch, I saw another Detectorist down the beach 100 yards away almost running and swinging his detector like a Mad Man and looking frustrated and not having a good time. By the time he got to me I had put away my gold and, as usual, welcomed conversation with another Detectorist. First words out of his mouth were;
“Have you found any gold?!” He appeared to be in full panic mode.
“Yes”, I replied with a broad smile.
Suddenly, he turns away as if disturbed and, before I could say another word, he went almost running in the direction he came swinging his detector a foot off the ground muttering something about where’s the gold? He is looking for the elusive gold I am sure he’ll never find. This old story got me thinking about how much ground/sand is not covered by the search coil when a Detectorist takes a normal stride down the beach swinging his detector?
The average male has a walking step by step stride of about 30” while a female has a stride of 26.4” (Chat GPT). If a coil has a length of 11”, this would imply that a Detectorist would miss about 19” (male) or 15.4” (female) of ground coverage per swing. In other words, with a normal stride, a Detectorist would be missing 75% to 70% of the ground (and targets) under foot. But do Metal Detectorists take normal strides?
In personally viewing beach videos on Metal Detectorists actually hunting beaches, I found that Detectorists usually take 2 types of stride with a single swing (e.g., left-to-right); a normal stride with a swing as each leg moves forward or a two-step stride swinging the detector every other step. Neither type of stride-swing combo is efficient or ideal for maximum target recovery. Indeed taking 2 steps per swing is so inefficient that it is not considered further in this post. I would argue that the most efficient and productive swinging strategy is to use a toe-to-heal stride and swing the detector with each step.
If an average person’s foot is about a foot long and average coil is 11”, a Detectorist taking a toe-to-heal stride would miss very little. Indeed, instruction manuals and intro books on metal detecting discuss overlapping the coil slightly with each swing to minimize missing a target, particularly a deeper target. It is obvious from actually viewing beach videos of fellow Metal Detectorists in the wild ignoring the intro advice and taking large inefficient strides.
One argument to counter the differences between the two types of stride (normal stride vs toe-to-heal) is that both types of stride would ultimately cover the same amount of area, its just that the Detectorist with a normal walking stride would walk more miles (and be more exhausted). The normal striding Detectorist would cover different parts of the beach than the Detectorist with a much smaller toe-to-heal stride; although I’m not sure of any advantage here. But it takes more time to take a normal stride than a toe-to-heal stride resulting in less overall ground covered. The normal stride Detectorist would have a more difficult time finding a target line in the wet sand since his/her swings and found targets would be spaced far out. In addition, with a normal stride it would be more challenging to hear subtle targets, more difficult to keep your coil parallel and more difficult to maintain a small consistent coil to ground distance. Finally, with a normal stride a Detectorist usually takes less swing (i.e., covers less ground) because they are constantly moving fast forward and tend to abbreviate the coil swing end-points. When I see a Detectorist with a normal stride hunting the beach, it seems that the Detectorist is more interested in the end of a rainbow rather than what is under their feet.
In conclusion, if you want to find more targets decrease your stride; sometimes less means more.
Part II will discuss “The Swing”.

 

[robertk]

People take normal strides while detecting? How?? I don't take strides at all. I move the coil forward enough that it just overlaps the path of the last swing, and my feet do whatever small shuffle they need to do to keep up.

 

[cudamark]

If I'm looking for something specific, like trying to recover a lost item, or an area with lots of good targets, I grid and overlap to make sure I don't leave any gaps. Otherwise if I'm just trying to cover a huge area such as a beach or field that there's no way to cover before conditions change, I don't overlap at all. I want virgin ground under my coil at all times and try to cover as much ground as possible. Naturally, you have to use a coil size and swing speed appropriate for the recovery speed and sensitivity of your detector settings, and the depth of your expected targets.

 

[Terry Soloman]

Another "New Discovery" from a detectorist that started last week. Seriously, Duh?!

 

[3RDLIFE]

I learned to follow grids looking for fossils and sharks teeth. If the ground is soft enough, I drag a foot as I shuffle to have lines to follow.
More importantly is to narrow your search to the most productive areas you can via research and experience. Detecting over 3 feet of fresh beach renourishment sand is almost pointless.

 

[mtdoramike]

Metal detecting is all about efficiency: the more efficient you are the more targets you’ll find and the happy you will be in the hobby. Two of the root factors of metal detecting efficiency are the stride and the swing. In Part I, I discuss the efficiency of the stride and in Part II I discuss the swing. By maximizing the stride and maximizing the swing, the Metal Detectorist will maximize targets found.
Back story: I was hunting Melbourne Beach, Fl years ago and inspecting a 4 ft cut with my Excal II at a popular beach. I was swinging my coil up-and-down along a 4 ft vertical cut and soon came across a thin 14k gold chain and cross. As I was putting the chain and cross in my pouch, I saw another Detectorist down the beach 100 yards away almost running and swinging his detector like a Mad Man and looking frustrated and not having a good time. By the time he got to me I had put away my gold and, as usual, welcomed conversation with another Detectorist. First words out of his mouth were;
“Have you found any gold?!” He appeared to be in full panic mode.
“Yes”, I replied with a broad smile.
Suddenly, he turns away as if disturbed and, before I could say another word, he went almost running in the direction he came swinging his detector a foot off the ground muttering something about where’s the gold? He is looking for the elusive gold I am sure he’ll never find. This old story got me thinking about how much ground/sand is not covered by the search coil when a Detectorist takes a normal stride down the beach swinging his detector?
The average male has a walking step by step stride of about 30” while a female has a stride of 26.4” (Chat GPT). If a coil has a length of 11”, this would imply that a Detectorist would miss about 19” (male) or 15.4” (female) of ground coverage per swing. In other words, with a normal stride, a Detectorist would be missing 75% to 70% of the ground (and targets) under foot. But do Metal Detectorists take normal strides?
In personally viewing beach videos on Metal Detectorists actually hunting beaches, I found that Detectorists usually take 2 types of stride with a single swing (e.g., left-to-right); a normal stride with a swing as each leg moves forward or a two-step stride swinging the detector every other step. Neither type of stride-swing combo is efficient or ideal for maximum target recovery. Indeed taking 2 steps per swing is so inefficient that it is not considered further in this post. I would argue that the most efficient and productive swinging strategy is to use a toe-to-heal stride and swing the detector with each step.
If an average person’s foot is about a foot long and average coil is 11”, a Detectorist taking a toe-to-heal stride would miss very little. Indeed, instruction manuals and intro books on metal detecting discuss overlapping the coil slightly with each swing to minimize missing a target, particularly a deeper target. It is obvious from actually viewing beach videos of fellow Metal Detectorists in the wild ignoring the intro advice and taking large inefficient strides.
One argument to counter the differences between the two types of stride (normal stride vs toe-to-heal) is that both types of stride would ultimately cover the same amount of area, its just that the Detectorist with a normal walking stride would walk more miles (and be more exhausted). The normal striding Detectorist would cover different parts of the beach than the Detectorist with a much smaller toe-to-heal stride; although I’m not sure of any advantage here. But it takes more time to take a normal stride than a toe-to-heal stride resulting in less overall ground covered. The normal stride Detectorist would have a more difficult time finding a target line in the wet sand since his/her swings and found targets would be spaced far out. In addition, with a normal stride it would be more challenging to hear subtle targets, more difficult to keep your coil parallel and more difficult to maintain a small consistent coil to ground distance. Finally, with a normal stride a Detectorist usually takes less swing (i.e., covers less ground) because they are constantly moving fast forward and tend to abbreviate the coil swing end-points. When I see a Detectorist with a normal stride hunting the beach, it seems that the Detectorist is more interested in the end of a rainbow rather than what is under their feet.
In conclusion, if you want to find more targets decrease your stride; sometimes less means more.
Part II will discuss “The Swing”.

Can you do an instructional video of that and post it? Some people learn better with visual aid. My wife is the same way, I usually try and do a grid pattern, but she will just start swinging away, way faster than I do. But I can't complain, she finds way most stuff than I do because she covers more ground. Yes, she has found way more gold and silver than I have. So to each his or her own when it comes to swinging a detector.

 

[Carl-NC]

Here is an illustration of what a typical 10" coil detection pattern looks like:

This shows is an "isodetection" curve which is a line of equal detectability. What this means is that a barely detectable coin at 9" at the center of the coil will be barely detectable at 7" at the edge of the coil. The curve is roughly a circular arc and varies with target size and depth, but this is about right for an average coin target. Concentric and DD are about the same, especially for deeper targets.

Let's say we sweep the coil with no overlap:

Assuming the curve is for a barely detectable coin, the gray area represents where the coin will be missed. If the coin is buried 8.5" deep (dashed line) then you've got about a 50-50 chance of hitting it.

Now let's sweep the coil with a 50% overlap:

The area of undetectability is much smaller, and you should always be able to hit the coin at 8.5". The drawback, of course, is that now it takes twice as long to cover the same ground area. Whether this makes sense depends on what you are looking for and how deep it might be, and also on whether you're doing a gridded search or a free-roaming search.

The sweep can also be considered. I see some people swing close to a 180° arc while others have a shorter sweep arc. Here is a 180° sweep with a 50% coil overlap:

The problem is that the extreme ends of the sweep overlap by close to 100%. That is, a good part of the sweep is re-hunting already hunted ground. Let's shorten the sweep to 90°:

Now the overlap is close to 50% for the whole sweep, so that part of it is more efficient. And given the same sweep rate (I usually use 1 m/s) a 90° sweep will take half as long as a 180° sweep, yet cover 70% of the same sweep width. In other words, for the same detecting time, a 90° sweep will cover 40% more ground than a 180° sweep.

IMO, using a shorter (90°) sweep arc makes sense pretty much all the time. Using overlapped swings only makes sense if you are trying to cover 100% of a given area. Often if I'm hunting large areas (parks or a stretch of beach), there is no way I'm going to hunt the whole place so a random walk with no overlap is really no different than staying in a small area and overlapping 50%. It a statistical game and the odds are about the same.

 

[Carl-NC]

Addendum...
The sweep illustrations in the last post aren't quite reality; a 90° sweep with 50% overlap would effectively look like this:

That is, more of a zig-zag motion. As such, some of the sweeps end up more than 50% overlapped. Here is what a no-overlap sweep would look like:

Even though there are areas of no overlap, there are also areas with overlap. Let's take one more case:

Now there is even less overlap, but you are actually covering more ground area. The drawback is you are not covering all of the ground. But in those cases where you'll never be able to hunt the whole area anyway, this case actually gives you more detected ground per hour than the other cases. It should give you better odds.

 

[Loco-Digger]

Another "New Discovery" from a detectorist that started last week. Seriously, Duh?!

Terry it appears he's been here for about 12 years. It's his epiphany so let him elaborate. No harm, no foul...

 

[Tesorodeoro]

Another "New Discovery" from a detectorist that started last week. Seriously, Duh?!

Coming from someone that has taught many beginners the basics? Hmm.

 

[mtdoramike]

Another "New Discovery" from a detectorist that started last week. Seriously, Duh?!

Terry, you must have watched the tutorial video I was asking about.

 

[LawrencetheMDer]

Very good discussion and, in part, purpose of my post. But glad knowlegeable MDers are contributing but main hope is Beginners read this post and think about their swing. Also, if you're taking a normal stride while hunting and think you're covering the whole beach or open area, you're dreaming. Hope you also enjoy my next post (Part II) about circular vs pendulum swing.