Browsing articles in "Scuba Tips"
Sep 15, 2019
Guest Author

Tips for underwater metal detecting for treasure hunting and archaeology

Tips for underwater metal detecting

Metal detecting is an amazing hobby. It helps us unearth many relics and know more about the history of our ancestors. Many want to take it to the next level and hunt underwater treasures. In this article, I will give a few tips that will help in your next diving adventure.

Do your homework

Before going for a hunt, you need to do some research and look for promising locations to increase your chances of finding something precious. This is especially important for shipwreck diving.

You have to gather as much information as you can about the ship. This includes the departure and arrival ports, the cargo and its trajectory. This type of diving is very difficult, needs experienced divers and a lot of expensive equipment. However, if you were lucky and found a Spanish shipwreck full of gold, you are going to be rich, very rich!

Pick the right metal detector

To pick the right metal detector you have to take into consideration the depth you want to dive to and whether the water is salt or fresh. There are two types of metal detectors: VLF and PI. Each one of them has its pros and cons.

Technology type

VLF (very low frequency): the crashing majority of the devices on the market are VLF. Their operational frequency ranges from 4 to 30 kHz. They are very good at distinguishing between different metal types; this will save the diver a lot of time. He will know what type of metal is buried under the sand before even digging it.

If the machine indicates that the buried item is, for example, gold, he will (obviously) dig it. If not, he keeps looking for other interesting targets.

The problem is that this type of detectors isn’t suitable for saltwater. The mineralization will hinder its performance and it will emit many false signals making it useless. So it is recommended to use them only in freshwater.

The PI (pulse induction): is suitable for scuba diving in saltwater and can perform well when used with salt wet sand. The minerals don’t affect its depth range. Their downside is that they can’t discriminate; they will beep whenever they detect a metal. In this case, the diver has to dig in order to find out what is buried underneath the sand.

Operational depth

If you want to hunt shallow creeks and ponds, any metal detector (even cheap entry-level ones) can do the job. They can be submerged up to the control box.

If you want to go a little deeper (snorkeling), then you need a waterproof metal detector. You can get a reasonably priced device that can run up to 10 feet underwater. They are usually VLF machines. So they are suitable for freshwater.

If you are a professional scuba diver, then you need an underwater detector that can operate up to 200 feet. These are very expensive and meant for professional use.

Use the right accessories

In addition to the appropriate scuba diving equipment and to the metal detector, there are some tools that can make your hunt easier.

You can dig many targets with your hands but a sand scoop will make things easier and faster. It is recommended you choose a scoop with a wooden handle to reduce the weight.

You also need a pinpointer, which is a mini handheld detector with a limited range.

Metal detectors have onboard speakers. If you want more comfort, you can use waterproof headphones.

Maintain them in a good shape

Before going for a dive make sure there are no cracks in your devices. Check the O-rings frequently. Ensure they are in good shape and sand-free. Then lubricate them with silicone grease.

Use the right technique

It depends on the detector type. VLFs are motion detectors, you need to swing the coil from side to side in order to detect something. PIs are static detectors, they can detect metals even if they are motionless.

If you’re hunting shallow waters, relax and let the currents move you back and forth. Focus on low spots and around the rocks and scan them multiple times with your detector. The goodies are usually there.

Practice and practice more

Treasure hunting underwater is a lot more difficult than on land. Being a professional detectorist isn’t enough. You need to get sufficient training from professional divers. You can find many schools where you can get your diving certificate.

The same applies to divers who never used a metal detector. You need to learn how to use your device before going for a dive. This includes doing some air testing. This means passing some metal object in front of the search coil back and forth to get used the audio signals emitted by your machine. You need to read the user’s manual carefully and play with the settings to get used to them. I highly recommend that divers collaborate with detectorists to exchange skills.

About the Author

Rob Green is passionate about metal detecting, history, and archeology. He is also interested in shipwreck diving. You can follow him on his blog where you can find many tips and tricks about this hobby.

Jan 31, 2014
Guest Author

How To Decide Whether To Learn To Scuba-dive

Scuba diving is a very popular hobby, with millions of people enjoying the sport all around the world.  If you have a yen to learn to scuba-dive, this article gives some pointers that may help you choose how to go about it.

What is Scuba-diving?

Scuba diving involves swimming underwater, carrying your own oxygen supply so that you can stay under for much longer periods than if you were just holding your breath.  Obviously, as with any potentially dangerous sport, there are carefully developed safety procedures that are an essential part of both learning to dive and enjoying the activity on an ongoing basis.

What equipment do I need?

This depends to some extent on where you are diving, what experience you have, the temperature of the water and the depth you are diving to. If you are diving in colder waters, for instance, then you will need to wear protective clothing in the form of a wetsuit, possibly over a rash vest to prevent chafing, which allows a small layer of water in between the wetsuit and your skin.  This then warms up to body temperature and will keep the chill off for a while.

Decide to scuba-dive with Jessica Duggan

If you are diving for longer periods, as you become more experienced, or are venturing into really cold water, a thermal drysuit which, as the name implies, keeps you completely dry, is a better option.  If you learn by going on a course in Thailand, or the Red Sea, for instance, then the water is usually warm enough for the wetsuit to be unnecessary.  Other equipment is usually included on loan for the duration of the course, but if you become hooked on this exciting pastime, it is best to seek advice from an expert supplier such as who can provide everything you need.

Other essential equipment includes a buoyancy compensator device (BCD) to control whether you ascend or descend in the water, an oxygen tank and regulator, to control your oxygen supply, a face mask, possibly as part of a helmet, fins, torch and a watch capable of being underwater to a depth of around 40 metres.

Where do I start?

Living in the UK, there is a great deal of useful information from the British Sub-Aqua Club (BSAC).  This includes lists of local diving clubs, qualifications, having a go at a “try dive” in a local swimming club, under the guidance of an instructor from your local club as well as an extensive section on the all-important diving safety. The BSAC organise diving course for all levels, from complete beginners to advanced techniques such as dive leader or advanced diver and award qualification cards on successful completion of the course.

The internationally recognised diving association is the Professional Association of Diving Instructors (PADI), and in the UK you also have the Sub Aqua Association (SAA) similair to BSAC where it is club based training and scuba diving. Similair information and training is given from each. You need to check with the dive location you are going to see if they recognize PADI, BSAC or SAA as some are more inclined to one organisation.

UK or overseas?

It’s probably a good idea to start with a “try dive” close to home, to make sure that you can cope with being underwater (not everyone can).  After that, you may be tempted by taking a holiday overseas, to warmer climes, such as the Maldives, the Caribbean, Thailand or the Red Sea, all of which offer courses for the basic PADI qualification, usually lasting around 5 days.  The attraction of this is that it is idyllic swimming and diving in warm, clear water, without having to worry too much about becoming cold, or having to use a torch to see anything.  The downside, of course, is the cost. Living on board a luxury “floating hotel”, with full board and all equipment and instruction provided, is likely to be between £2000 and £2500 in the Maldives, for instance, not including the flight there.  Thailand is far cheaper, with the same holiday PADI course being around £300 to £400, plus flights.

Perhaps the best of both worlds would be to spread the cost of the basic qualification over a few weeks in the UK, then indulge yourself by going overseas for the next stage!

Featured images:
License: Image author owned


Jessica Duggan has been involved with the travel industry for several years, including working for 2 seasons on a “liveaboard” in the Mediterranean, which catered for both scuba diving and snorkeling holidays.  She is well aware of the need for stringent safety procedures in diving, having seen a couple of potentially serious situations.  She enjoys most water sports, including sailing and canoeing, but confesses to not having the balance for surfing.

Feb 26, 2013

Learning to Scuba Dive

When people look at learning to scuba dive, the normal course of action is to go with the closest or cheapest school at the time. This is something that should not be over looked because as with everything there are good instructors and bad instructors (in many ways) and the different training groups, such as PADI, SSI and BSAC and they all have their unique way of getting you in the water. Now I can’t comment on BSAC or SSI because I have not attended those courses, or met any instructors that teach that way into scuba diving but I am going to comment on PADI and the general attitude of Instructors I have met around Cornwall, UK. I will be getting my hands on the books for BSAC and SSI at some point in the near future to compare them myself and will comment about that when I have.

Learning to Scuba Dive

Always learning

What I can talk about is character and quality of teaching, and which ever entry you wish to take into the sport that is something you should be looking out for because as a sport it is extremely dangerous if you have not been given the correct instruction. If you have an instructor that doesn’t feel teaching his/her students is a chore and you are able to bond with them then the experience and the knowledge you will learn will improve your ability when in the water. It is also important to remember that the limited learning with the PADI Open Water qualification does not teach you many of the important things about diving but it gets you in the water quickly, which is where you are going to get the most experience no matter who the instructor is.


Now the instructor and school you choose are going to try selling you more, it has to be taken into consideration that they are giving you a service you are paying for that opens your world to something special, how-ever they are there to make money, many of them are self employed and running the school or are only brought into a school when they are needed (for PADI at any rate) and that is why some of them (as they are only human and we all get bored with our jobs at some point) may not be as good as others. It is important to feel comfortable with the person you are learning to scuba dive with, that they are not going to take advantage of you (or more precisely your wallet) and have a manner that what they are saying is clear. This is something they are shown in the PADI system when they become an instructor because of the role play and presentation that they go through, and if they have a good character they will understand why it is being taught that way and will become a really good instructor.

As I have already said, they are supplying you with a service that you are paying for, and while it doesn’t seem like you have much of a choice with limited schools in your area, it is important that you meet your instructor and dive master before you get in the water, a great way to get to know if you are comfortable with them is to meet up for a drink before you part with any money in a neutral place that will make them relax a little more than if you were just talking to them in the shop (where they have to be constantly on guard selling things if they can). While they are still going to be trying to sell you a course and gear it will give you a good chance to ensure you feel confident that the person who is going to be leading you through this wonderful experience is someone you know will be looking out for you at all times. Having a humourous attitude is a bonus and if they have experienced a few thousand dives instructing, as well as personal recreation it will give you a more relaxed atmosphere to learn in. It is still your money and your life that you are putting in their hands and if you don’t feel comfortable with them then don’t let it put you off but look for another school, for an excited learner (I was one not so long ago) it is hard to be objective because you have pushed yourself to experience diving and you just want to get in the water, but always remember that there are plenty of schools and you shouldn’t limit yourself to one. Do not be afraid to ask questions, even ones that feel scarey to think about, like:

‘Have they ever had to deal with an emergency?’
‘Have they ever run out of air?’
‘Have they ever lost a diver?’

As I said these are not questions you should be afraid of asking at this point and the body language should be looked at to see if they are being honest, little things like pauses, glances at each other before they answer, seniority of answering and the like. I hope you can see now why I personally feel that getting them away from the office/school to a neutral place so you can both relax is important, this is your money you are about to spend, and your life you are putting in the hands of someone else to guide you into what is going to be something you will always find an excuse to go do.


The great thing about learning to scuba dive with PADI is that it gets you in the water within a few days as a basically qualified diver (to a depth of 18m and with pressurised air) and you can then take that with you anywhere in the world, the only real problem I have with the basic course is the lack of amount of information and skills in an emergency situation, they cover the basics like the Controlled Emergency Swimming Assent (CESA) and the importance of dropping your weights and becoming buoyant at the surface, but there wasn’t really much after that like how to get to the shore with a buddy that is having problems and how to get them out of the water, or even how to bring a diver up from depth when they are in difficulty. This isn’t even covered in the advanced open water and you have to wait till you get to the rescue diver course till you are taught it in detail. I personally feel this is something that should be covered in the basic open water course with PADI because of the importance of having that knowledge as a novice diver. If you have the opportunity the level of rescue diver is something that all divers should aim at with the PADI system till they change it (probably never will though) so you have a greater confidence in the water and with your kit, and others that are with you will respect any decisions you may have to make in an emergency. While you may be trained in this area and others not, do not take complete control ordering people around but listen to others because they may have noticed something you have missed.

In Cornwall at the South-West tip of the UK I have met a few instructors and dive masters and was impressed by the ability and knowledge of them all, there was only one I would not go to for a course because he had an inane habit of lying, or embellishing the truth and I wasn’t impressed but to mention the name of the school and instructor at this time would not be fair. There was many a time when I was learning that I asked my instructor questions that were not in the books and the confidence he gave me in answering my questions was brilliant, he did get a little annoyed because there were things I would ask about that for a beginner are not thought important but as I explained before there are things you should know when you are first qualified, mainly so you have more respect for your equipment and your buddy that gets a little overlooked when you are excited at seeing that first fish at 15m and start following it, forgetting about the rest of the group, it is something everyone does at first from what I have personally seen other divers do as they go through the basic open water qualification with PADI.