Have you been thinking of buying an underwater metal detector? In this article you will learn to see between the underwater metal detector and a waterproof metal detector. You will understand how they differ from each other and what they can and can’t do.
What is the difference between Pulse Induction and VLF. There is a separate section containing rating of the best metal detectors for both beach and underwater hunting.
Do you know?
Underwater metal detector and metal detector for beach hunting isn’t it one and the same thing
First of all, you have to understand that all metal detectors are conventionally divided into underwater ones (those that you can completely drown into the water up to 70 meters deep and the ones that can function in a brackish water) and waterproof metal detectors that are used for coastal and beach treasure hunting (such detectors can be put up to 5 meters deep into water and they demonstrate poorer productivity in brackish water).
So what makes these metal detectors different?
The thing is, that manufacturers of top metal detectors try to design them as multi-purpose ones, so they would be in high demand among the majority of treasure hunting fans. Which means that a waterproof metal detector is a device capable of functioning both on the ground (moreover, it was designed for this) and under water at insignificant depth.
Waterproof metal detectors typically have screens and function using a classical technology common for all metal detectors; it is called VLF (very low frequencies) and they can be put under water at some limited depth.
Most of professional underwater metal detectors doesn’t have a LED display, they use Pulse Induction (PI) technology and can be drowned quite deep into water. For convenience some underwater metal detectors have separated control unit and search coil.
This is really handy, since the control unit is usually fastened to a waistband and you search the pond bottom by means of a coil fixed to a metal detector shaft. This way it is easier to perform underwater metal detecting.
VLF and Pulse Induction technologies
Standard ground metal detectors (those using VLF technology) generate constant electric current inside the coil transmitter and the change of the receiver voltage phase or amplitude indicates the presence of metal objects under ground.
Metal detectors using pulse induction (PI) generate electric currents for the transmitter, which turns on for some period of time and then abruptly turns off.
The coil field generates pulse vortex currents in the object they detect and analyze the pulse attenuation in the receiver coil.
PI metal detectors are irreplaceable during coastal and underwater treasure hunting as well as on highly mineralized soils.
The device productivity doesn’t depend on water or ground influences. Such devices demonstrate the same successful productivity both under water and on the ground.
That’s why PI technology is used in underwater metal detectors. They demonstrate good results when searing on sandy beaches and wet sand metal detecting.
The depth of objects detection in the ground and in brackish water is larger if compared with the results obtained by VLF metal detectors.
VLF is good for treasure hunting on the ground, but under water such devices show significantly lower productivity and the detection depth is less if compared with those of PI ones.
If you do treasure hunting professionally and use VLF instead of a PI metal detector, you essentially decrease your chances to find something really valuable.
Which metal detector to choose?
You should make this decision after making your mind as for where you are going to go treasure hunting – on the beach and around coastal area or deep under water.
Most of treasure hunters dive not that deep, since all gold and silver jewelry that people loose in water is usually located in a coastal area.
If your task is to go around the beach, search not far from it and you will maximum get waist-deep under water, you should get a waterproof metal detector for beach hunting.
For example, this can be Garrett AT Pro or AT Max. Going up to 3 meters deep is also possible both with Minelab CTX 3030 and with Minelab Equinox 800. Such metal detectors identify even small targets, for instance, rings or bracelets.
But if you’ve decided to become a professional underwater treasure hunter, you should turn your attention to a professional underwater metal detectors.
For underwater treasure hunting you will need a PI metal detector. It performs better on a sandy beach and brackish water, easily tunes out of noise.
However, these detectors aren’t as sensitive as VLF detectors and they don’t search that deep. Here we can recommend you to buy one of the most affordable underwater PI-metal detectors —Tesoro Sand Shark.
Waterproof metal detector for beach hunting
This model is presented by White’s company as a completely waterproof device designed for underwater, coastal and beach hunting. It can function both on the ground and under water, up to 7.5 meters deep (when using special waterproof headphones). The device set includes: 9,5” mono coil, box for 8 batteries (AA) and underwater headphones.
This metal detector has 2 operation frequencies – 3 and 15 kHz which ensures its efficient functioning for various tasks and search conditions.
Whites Beach Hunter ID 300 has 2 search modes: All metal and discrimination. The first mode performs all metal search. It is good for underwater hunting and it simplifies identification of the goal center.
The second mode is discrimination with 3-tone identification of objects and LED indication. When using this mode, each tone and LED color corresponds to the certain metal sector, which helps you easily and fast define the objects.
Garrett AT Pro
This is a classical model produced by one of the oldest manufacturing companies and this is the best seller in the USA.
Garrett AT Pro is an amphibian metal detector due to which you can put it completely under water up to 3 meters deep. Its high operation frequency allows finding even the smallest objects which makes the device a perfect one when going jewelry hunting (gold and silver one) on the beach.
There are two things I like about this detector – its multi purposeness (it demonstrates high efficiency both on salty sand and on the ground) and the fact that this device is a time-proven one.
As an option you can consider AT Max – it is the same as Garrett AT Pro, but it was a bit more improved.
Minelab CTX 3030
This metal detector was produced in 2012, but it is still Minelab top model. Metal detector Minelab CTX 3030 is designed for treasure hunting at any weather conditions and on any type of territory; both on the ground and up to 3 meters under water.
This metal detector is equipped with the newest devices, so even nowadays it is still up to date. Only this model has a GPS receiver unit integrated with Google Maps.
Let me remind you, that there are no other manufacturers in the world who were capable of installing a GPS receiver unit into their devices.
In general, this is one of the best and multi-purpose metal detectors in the world, which has only two demerits – its price and weight.
Underwater metal detectors
Minelab Excalibur II
This is a classical device for underwater treasure hunting. We can’t even count how many treasures and troves were found by means of it. This is a time-proven and very quality metal detector and after buying it you can go underwater treasure hunting right away. Excalibur II is considered to be the most high-tech underwater metal detector and I guess you won’t find anyone who will argue with this.
You can dive up to 60 meters deep with it; it has a highly efficient discriminator which can see between ferrous and non-ferrous metals.
This metal detector uses a unique technology of broad band scanning (BBS) that works with 17 frequencies simultaneously in the range from 1.5 kHz to 25.5 kHz. The device has a pin pointer by means of which you will identify the target center. The metal detector has Koss waterproof headphones in its set and a lot of other stuff.
We should mention that Excalibur 2 uses the technology of signal amplification by the coil (RCB). The coil with RCB technology amplifies any weak signals from small objects or deeply resting ones; due to its design the coil simultaneously suppresses interference and false signals.
The metal detector case color is bright and fluorescent, due to which you won’t loose track of it in muddy water. The device has S-shaped shaft and it is more convenient to use for underwater treasure hunting than a straight one.
The device is powered by eight AA batteries or by accumulator; its capacity is quite large – up to 1000 Ah. Though the metal detector weighs 2.5 kg, you all know that things become lighter under water.
Garrett Infinium LS
This device is promoted by Garrett as a completely waterproof one capable of working both in shallow waters and quite deep underwater – up to 60 meters deep (when using special waterproof headphones).
Its 10″х14″ DD coil is a waterproof one. ‘AA’ alkaline batteries and headphones for ground metal detecting (not waterproof ones) come in the device set. You will also get a DVD disk with a manual to simplify and speed up the process of mastering the device.
This metal detector was designed to function in highly mineralized medium, therefore it feels quite ok and performs efficiently when using it in sea water.
If you compare the device with Minelab flagship device, the latter is 1.7 kg heavier; you can drown it up to 60 meters deep. When comparing their functionality, Infinium works using 96 frequencies which ensures faultless work both in brackish and fresh water. Moreover, its multi-frequency technology allows it easily detect both small and large targets.
It doesn’t matter what you are looking for – a golden ring deep down or something larger. This metal detector has a set of specialized coils – Mono and DD ones of various sizes and configurations. This allows to select the most proper coil for your search area.
This is an underwater metal detector that functions using 2 frequencies – high (15 kHz) and low one (5 kHz). The high frequency easily detects small targets including those made from precious metals and 5 kHz frequency allows searching large sized objects.
As its designers say, the metal detector was created to work in brackish water. That’s why if you’ve decided to dive with a metal detector in the sea, Fisher CZ-21 is one of the perfect options. Its maximal depth of immersion is 76 meters; at that it can function both in brackish and fresh water.
Two signals VLF (5 or 15 kHz) that penetrate deep provide twice more information for the target identification. The device has a function of compensation of destabilizing effects of salt water, tunes out false signals generated by brackish water.
The ground balance function is adjusted manually and a tone signal informs you about the target found. At that there is an amplifier of weak signals that allows to hear them.
1280X-8 is an underwater metal detector made by American manufacturer Fisher. You can put 1280X-8 up to 76 meters under water. Fisher made its 1280X-8 completely easy-to-use. Maximum number of the device settings are adjusted automatically – threshold signal, ground balance, compensation of salt water influences.
Fisher 1280X-8 has sequential metals discriminator with the ability to adjust the metal detector sensitivity. Fisher 1280X-8 has 3-tone audio target response, volume adjustment. Visual control of the target response. Increased time of offline work.
Garrett Sea Hunter Mark II
Sea Hunter Mark II is a professional underwater metal detector made by American company Garrett. You can put Sea Hunter Mark II up to 65 meters deep into the water. Waterproof headphones and straps to fasten the device to a diving suit come in the device set.
The settings are quite simple and flexible at the same time – these are discrimination, threshold tone and sensitivity.
The device design is rather ergonomical – the control unit can be fastened to upper, middle or bottom section of its shaft. Also you can assemble the metal detector without using the middle shaft for more comfortable hunting at tough conditions.
Sea Hunter Mark II is a metal detector based on PI search technology. Application of this technology allows Garrett Sea Hunter Mark II get an immediate target response.
Tesoro Sand Shark
This metal detector uses a microprocessor technology due to which it demonstrates high efficiency both under water and on the ground.
The device operation frequency is 12.5 kHz. It can dive up to 60 meters under water, which allows using the metal detector for professional treasure hunting when scuba-diving. In this case you can remove the middle shaft and make the device smaller sized and more convenient to use.
The shaft itself consists of three sections with additional length adjustment, which makes it a multi-purpose one both for underwater and ground treasure hunting as well as it becomes a huge advantage while transporting the device.
This metal detector is powered by 2 АА batteries, its operation time is about 15 hours in average, it has batteries in the set for a ‘quick start’. There is also a function to test the batteries charge, which is very convenient; of course – nobody would like to find out that the batteries are low after 15 minutes of deep diving.
As for the sound identification – the device has a mute mode and adjustable threshold tone.
Peter Harrington is actually the founder of UnderCoil. He is keen on relic hunting, antiquities collecting and a big fan of aquarium husbandry.
His favorite season is early spring. Peter likes studying new models of metal detectors and creating new site content. However, he’s not into social networking stuff.