10 Underwater Metal Detecting Tips for Your Next Hunt

Underwater Metal Detecting Tips You'll Love

Combining land hunting with underwater hunting can increase the chances of finding targets. Detecting underwater can be more difficult than on land and often requires specific equipment and training. There are also very specific rules and laws pertaining to underwater detecting that should always be followed to ensure your safety and keep you out of trouble. 

Detecting in water can be a hugely rewarding experience. In this article, we will discuss 10 underwater metal detecting tips to remember for your next metal detecting hunt to ensure you have the most success possible and the most fun!

Before we get started, I encourage you to check out the guide below, where you’ll be able to compare popular submersible metal detectors against one another, which should hopefully be helpful if you’re currently seeking a new detector:

Garrett AT Max$$$Waterproof to 10 feet
Fisher F22 Fisher F22$$9″ Triangulated Concentric Coil
Garrett Ace 400 Garrett Ace 400$$$8.5 x 11" DD coil
Minelab Vanquish 540$Search Modes: Coin, Relic, Jewelry, Custom, All Metal

1) Plan Out Your Trip

Making sure you start your underwater hunt with a plan will help you make sure you are not wasting time, gas, and money. Summertime is probably the most enjoyable time to underwater detect.

Warmer temperatures will ensure the water temperature is higher, requiring less equipment. Of course, you can metal detect underwater any time of year, but colder months (or deeper water) will require specialized equipment for safety.

Be sure to check the weather forecast, ensure you have the proper gear, ensure you are properly trained in use of the equipment, know where you want to hunt before you leave, and study up on the laws surrounding metal detecting underwater. 

Planning your trip in advance will also allow you to make sure you have the proper gear necessary for your trip and allow you time to become familiar with your gear, if it is newly purchased.

2) Check Your Gear

So, you have decided to underwater metal detect, and planned to visit your local lake, river, stream or ocean. Now it is time to make sure you have the proper gear. Depending on the time of year, water temperature, and water depth you are planning to hunt in, you may need a full wet suit. Cold water takes heat from the body a full 25 times faster than cold air. If the water and weather are warm, a warm water wetsuit would do the trick. 

A good set of fins is necessary for deeper dives. It is important to ensure that if the water is deeper, proper breathing equipment must be used. Shallow diving may not require special breathing devices or will require a simple snorkeling setup.

Diving goggles will be necessary and a flashlight or other light source to be able to see your targets and surroundings more clearly is a must. You will want to bring a long-handled trowel to dig with. 

Some may want to take a metal detecting pinpointer along, also, so long as it is clipped to your suit or wrist. These can fit into small cracks in rocks that larger coils will not fit into. Waterproof headphones are a must for underwater detecting, as you will not be able to hear the sounds well in the water.

Some may want to bring along a chest harness, as swinging a heavier metal detector (models for deep water hunting are typically heavier) back and forth for hours while swimming will get tiring. The harness will take the weight from the arms and make exploration easier. A tool belt to keep everything organized is recommended.

You will also need a mesh pouch or container of some sort to keep all that loot in! 

3) Choose The Right Detector

Next comes one of the most important pieces of gear: the metal detector! It is important to choose a model that is fully submersible, and ensure the detector is waterproof to the depth you require. Some models are only waterproof to 10 or 20 feet, so if your dive will be deeper, you will need a detector that will work at greater depths. 

For shallower water, there are several available models that range from 10 to 20 feet submersion. The Garrett AT Pro and Garrett ATX are some of the most popular and most highly recommended detectors for shallow water and beach hunting.

Both are fully submersible up to 10 feet and have plenty of features for beginner to advanced detectorists. The ATX is a pulse induction detector (hence the high price) and is built for extreme environments.

The Nokta Simplex and Nokta Gold Kruzer are also submersible up to 10 feet and 16.4 feet, respectively. Both models are also easy to use for all detectorists.

There are also several models available for those wanting a deep-water detector. The Garrett Sea Hunter Mark II is submersible up to 200 feet, has pulse induction, and includes submersible headphones with great sensitivity. This model works well for beach hunting or diving. 

The Tesoro Sand Shark has many of the same features as the Garrett Sea Hunter Mark II, including 200 feet submergibility. This model also has pulse induction technology, so it works well in wet, sandy and saltwater environments.

Expected battery life for this model is 10 – 20 hours. Fisher has 2 models called the Fisher 1280-X Aquanaut and Fisher CZ-2 that are submersible up to 250 feet. The Aquanaut runs at a very low frequency (VLF) and is more susceptible to interference from wet sand. It does have manual ground balancing and discrimination to help balance mineralization. 

This model also has a rechargeable 75-hour battery life, so it is perfect for longer trips. The CZ-21 is a pulse induction machine, so it is heavier than other models, but goes deeper into the seabed and discriminates better than other models.

The models listed here are by no means the only waterproof models available. These are, however, some of the best underwater metal detectors and the most highly recommended models. Remember, just because a detector says it is waterproof, does not mean it is suitable for diving. 

Each model will have its own depth rating, and that should be followed closely to ensure the safety of the machine. It should be noted that it is always a good idea to shop around for a good detector. Some retailers like Walmart of Amazon often have discounted products. Detectors can be purchased used; just ensure it is in full working condition and check how many hours it has been used.

4) Know Your Equipment 

Before entering the water, you should familiarize yourself with all the equipment you will be using for your hunt. If you are purchasing a new detector, get to know it by doing a series of tests. Find items like iron, pennies, dimes, nickels, quarters, gold, and jewelry and get to know the sound and readout your detector makes when targeting each of these. 

Not all underwater metal detectors work well on land, so when doing tests, it can be helpful to set up in a room with little to no electromagnetic interference (no cell phones, items requiring power turned off, no Bluetooth devices, etc.). If your detector works well on land and in the water, practice in shallow water or beach areas first.

Become familiar with the weight, sounds, and readouts your machine gives you. This also gives you a chance to familiarize yourself with the discrimination, sensitivity, and notch features of your detector. Detecting in saltwater and wet, sandy areas can give false readings if sensitivity is too high, so this is a good time to figure out how to ground balance your machine.

Besides becoming comfortable with your detector, familiarize yourself with each piece of equipment you will utilize during your hunt. Completely outfit yourself on land and become comfortable with the location, removal, and return of each piece of equipment that will accompany you into the water.

Be sure that any equipment requiring batteries, or a power source are fully charged before entering the water, especially visual aid equipment such as light sources. Depending upon the depth you will be searching, you will not want to be left in the dark if your light source runs out of juice.

5) Safety First!

Because salvage laws in the United States state that you must work 3 miles or more offshore, solo diving may not be the safest idea. Most professional underwater treasure hunters work in teams.

The same set of safety rules for divers apply to underwater metal detectorists, so be sure your awareness is high! Metal detecting while diving can take your focus off other factors, so it is important to remain aware of your surroundings. Other safety measures include:

If diving in deep water, ensure you are sufficiently trained in diving skills and equipment use. Know the warning signs of nitrogen narcosis and skills to cope with it.

Diving with an SMB (surface marker buoy) or flag to let boaters and other divers know your approximate whereabouts.

Keep other divers within visual and audio range, if using communications equipment.

Always dive during daylight. Night diving may sound romantic but is much more dangerous.

Remain aware of ocean currents, tides, and surface conditions.

Keep an eye on air tank levels. Remember that hauling more weight will make you use more air.

Simplify equipment to keep interference with metal detecting equipment minimal.

Keep headphones off unless actively searching. Be away that wearing headphones while ascending or descending can cause equalization issues.

Keep an eye out for marine life and avoid contact with delicate coral.

Have someone listening for boats, hazards, and changing weather conditions while you dive.

Be aware of salvage laws and local laws concerning salvage/diving/metal detecting.

6) Choose Your Depth

When just starting out as a detectorist, it is recommended to begin on beaches or in shallow waters. This will allow you to get used to the detector, familiarize yourself with the sounds and features of the detector, and get you started in the exciting world of underwater metal detecting. 

Try searching areas with plenty of recreational traffic such as beaches, shallow lakes, swimming holes, piers, docks, and streams. These areas will usually be home to a multitude of lost treasures from beachgoers. The most productive spots tend to be areas with the largest amount of people.

It is important to note that if you plan to metal detect in deep water, you should be certified in scuba diving. Diving equipment can be quite complex, and it is important for your safety to understand the ins and outs of diving and diving equipment before you plunge into deep water with a detector. 

If you are already familiar with diving, and you have familiarized yourself with your detector, it is time to take to the deeper water! As mentioned above, be sure you know the depth rating on your machine so as not to damage it. Always follow diving safety rules, along with metal detecting safety rules. Know the laws required for metal detecting and diving and always follow them.

7 Know the Laws

It is important to fully understand the laws concerning detection and salvage of underwater artifacts or treasure. These laws will vary from one country to the next. It is lawful in the United States to keep salvaged items that are found 3 or more miles from shore, with some restrictions.

Coastal states have separate laws surrounding underwater salvage, along with antiquity protection laws that absolutely should be followed. These vary from state to state, so it is important to check state laws before attempting to remove artifacts. 

If an underwater metal detectorist comes upon a shipwreck, it must be legally abandoned by the rightful owner before it is legal to remove anything from the wreckage. Shipwrecks owned by the United States government should never have anything removed from them.

It is also illegal to remove items from any vessel considered to be a war grave. Be aware that if you do find treasure of any sort, you will likely need to fill out plenty of paperwork. Do your research to ensure you are familiar with salvage laws!

It should be noted that shipwreck diving is recommended only for experienced divers. It presents the most challenges to divers, both mentally and physically, and can be very dangerous. It also requires more specialized equipment than traditional deep water detecting, and a modified dive boat.

Per state records, as many as 2,000 sunken vessels can be found along the Florida coastline, while the St. Lawrence River and Great Lakes hold a combined 13,000 shipwrecks. With so many shipwrecks you are bound to find treasure!

8) Rules for Artifact Recovery From Shipwrecks

If you do happen upon or purposely dive into a shipwreck, as mentioned above, there are specific laws governing them. The law of finds and the laws of salvage are important points of admiralty law. Salvage laws allow the person who recover’s the loot to negotiate with a vessel’s owner for payment of returned goods. 

The law of finds states that if a vessel has been left underwater without recovering the contents for a certain amount of years, the finder may claim the contents and the ship. The Abandoned Shipwreck Act of 1987 gives the United States government claim of all shipwrecks within territorial waters: up to 3 miles offshore (which accounts for the rules stating underwater detecting must be done 3 miles offshore). 

Always double check that a shipwreck is not designated in the National Registry of Historic Places. A World War I ship was sunk off the coast of New York. Divers recovered artifacts from the wreck for years, until it was proclaimed a Historic Place, disallowing all artifact collecting. 

There is also the Sunken Military Craft Act of 2004, claiming all sunken military craft as government property. Fines can be steep for disturbing these vessels, up to $100,000 per violation. The National Marine Sanctuary Act of 1972 designates marine sanctuaries and those require special permits for divers. 

The National Park Submerged Resources Center and Submerged Cultural Resources Unit maintain stewardship of wrecks within National Parks deemed culturally significant, such as the USS Arizona in Hawaii and B-29 Bomber in Lake Mead, Nevada. This may seem like a lot of rules and regulations, but each of these are in place to protect the rightful owners of vessels and their cargo, or to preserve historically important sites for others to see. 

9) Target Recovery Techniques

Begin by establishing a line on the bottom of the seabed, either imaginary or set up using rope with anchors. Once you have established your imaginary (or real, if you’ve set up your own) line along the bottom, swiping back and forth with 5 to 6-foot swipes. Watch the seabed or lakebed for holes, low spots, rocks, and valleys where items may have become lodged and know the water current so you can see what direction the sand is moving.

Going with the flow of the current will ensure you are not fighting against the current and keep you from tiring out quickly. This will give you an idea as to where targets may have become stuck. For harder beds, the long trowel we sorted out in the gear section works well at retrieving targets. You can simply use your hand to fan the sand out of the way if the bottom is soft and sandy.

When detecting in sand under 5 inches deep, move the search coil in semi-circular, overlapping motions at moderate speed. If the sand is deeper, slower sweeps are necessary. Ensure you are listening closely for faint beeps from the detector indicating deep signals. If your detector is multi-tonal, using zero discrimination will report all targets, allowing you to dig all targets while filtering out iron tones.

Keep sensitivity high enough to ID targets, but not so high it causes the machine to malfunction. Using maximum sensitivity and zero discrimination will offer the greatest depth, which is where many gold targets will be located due to their weight.

Long handled trowels make recovery of targets easier in rocky or clay soils. Most are stainless steel, which is strong enough to hold up against hard soils and will not rust. Longer handles also make the trowel more comfortable to use and can save your hands from scraping against rocks. If the sand is softer, it can simply be fanned away using hand motion.

Be sure you are fanning an area as large as your search coil, and constantly scan the area while fanning to ensure the target has not been moved. The current will help move any floating sand away leaving the search area visible. Some divers take a screwdriver or sand screw to help pry lose coins or other targets easily.

When items are recovered, it is important to keep them safe in a mesh bag or other type of container. Ensure that delicate artifacts are kept in airproof containers with water, so they do not dry out until they can be properly processed. The mesh bag or container you store your finds in should keep the items safe without the risk of them falling out due to a bump or a strong current.

If your find is too large to haul out without specialized equipment, be sure you have brought along some type of marker so you can find the object again when you have gotten the proper equipment or help. A GPS device specifically for diving will allow you to do just this. 

10) Enjoy Your Adventure!

One of the most important tips to remember when underwater metal detecting is to have fun! Enjoy the exploration, the joy of the detector buzzing in your ear, the excitement of digging that target, the potential for historical finds or riches. While there may be several rules and regulations, a lot of training, and specialized equipment necessary to get you underwater detecting, it will be a rewarding experience!

Don’t let all the rules and regulations make you shy away from this incredible hobby. You may just hit the mother lode and come away with a cache of coins or gold, or a very important historical artifact. Imagine that artifact sitting in a museum somewhere with your name and photograph sitting underneath. 

So, understand your equipment, know your laws, always be safe, bring a buddy or 2, and above all else, have fun!

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