Critical Factors to Consider Before Selecting a Metal Detector for Fresh and Salt Water Beaches
by Lee Wiese
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Updated 02-24-21
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Introduction. Metal Detecting beaches can be a
challenge for any cause of the ever changing beach conditions which can be encountered. This article will focus on beach condition changes and their affect on a metal detector's ability to operate correctly over the whole beach.
To start, there are major differences between fresh and salt water beaches
and choosing a detector that can operate just fine on a freshwater beach may
not be the right answer as a saltwater beach detector. That same freshwater beach detector may fail to operate properly or at all on a saltwater breach.
This article will address the two different beach types, multi-function (VLF) detectors and pulse induction (PI) detectors.
Today, there are over 100 detector models offered by manufacturers. There in a table at the end of this article of some of those models. The table has
just a few models listed for comparison purposes and note that some of the detectors have been given a ranking number. The ranking goes from one to
five with one being the highest rank. The source of information for this table and ranking comes from personal beach detecting experience while using
many different detectors and from comments concerning beach detecting and detectors on various hobby related forums.
The table has the manufacturers listed on the left side with various detector models below each of the manufactures' name. Listed across the top
of the table are the two beach types fresh and saltwater and below each beach type are the three section of any breach (dry sand, wet sand, underwater).
Color codes (green, yellow, red) are used to show the capability of each model on the various sections of the beach. On the far right side of the
table is the detector ranking scale (1 to 5) for freshwater and saltwater detectors. Only five detectors are ranked for each of the two beach types.
The capability of a detector to handle a given beach situation determines its ranking in the list. If no rank exist for a given model it just means
that the model isn't one of the top five best detectors for beach detecting.
This article does not recommend any specific detector to purchased for beach detecting even if a detector is ranked. The rankings are very subjective and
should only be used as a guide to your detector purchasing decision. Before purchasing a detector you must always consider where the detector will be
used. Will it be used for fresh or saltwater beaches and on what sections of the beach? The location of the saltwater beach can also be critical in any
choice, since saltwater beach mineralization varies from coast to coast (east coast, west coast or on a southern U.S. beach coast). Also other countries
may have specific beach detecting conditions that also could influence your detector decision. If you plan on traveling and detecting across the U.S. or
in other countries, do your homework to determine the best detector or detectors for your metal detecting adventure.
Freshwater Beaches can be found anywhere there is a nice lake, stream or river bank that can be used for swimming. Freshwater beaches offer a couple
of challenges to the detectorist both on the beach and in the water. Freshwater and saltwater beaches are usually divide into three major sections:
- dry sand,
- wet sand and
- underwater beach sand.
The major freshwater beach challenges that a multi-function detector must
overcome:
Freshwater beaches are usually well established and have been in the same location for many years and in some cases for more than a 100 years. The greater the age of a
freshwater beach the more metallic trash will be encountered by the detector. The major reason for more metallic trash at a freshwater beach is
that there is no corrosive environment that exist like on a saltwater beach, so the metallic material does not corrode rapidly or in some cases not at
all. This means metallic trash (bobby pins, pull tabs, bottle caps, nails, foil, etc.) cumulate over time on a freshwater beach. This also implies that
much more trash will be found in the deeper layers of sand and clay or mud bottom of a freshwater beach.
One of the reasons to detect a beach is to find jewelry and if the trash content of the beach sand is very high, the trash may mask a jewelry target
signal from the detector being used. When water detecting on a freshwater beach keep in mind that the underwater portion of the beach may have the
same level of trash as the beach dry sand. If this is the situation, you will be digging and retrieving a lot of trash and that is not much fun in
waist deep or deeper water. Hint: Try to always detect freshwater beaches in the fall when the water level is lowest. Low water levels expose more beach
and target retrieval become a much a easier task.
Another reason that freshwater beaches have more trash is that there are no swells (except very large lakes). Large swells and surf action remove sand and also take trash off the beach to deeper water. This is usually
NOT true for smaller inland lakes, rivers and streams.
Another thing to consider is that some detectors will operate correctly in dry sand but become unstable in wet sand or in the water. Always give
consideration to the effects that wet sand and fresh water have on a metal detector's operation before purchasing a detector.
The detectors used on a freshwater beach and in the water should have the following:
Must have features in a multi-function detector -
- waterproof to some depth level (only if you plan on water detecting),
- extremely fast target response (aids in target signal separation),
- very good target discrimination adjustment capability,
- coil interchangeability is extremely important to aid in target separation (small coils: 5", 8", 3x6", 6x9", etc),
- light weight and ergonomically comfortable for the user.
Want to have features in a multi-function detector -
- tone I.D. and / or optional digital display I.D. capability,
- ground balance capability,
- capability to also be used on saltwater beaches and in saltwater.
In summary; use the list of features above and compare them to the detectors ranked for freshwater beaches. The best detector choice will have many these
features. Always get other detectorists' opinions and input before buying. This article is just one input to your detector purchasing decision.
Keep in mind that using metal detector discrimination to mask out trash is
NEVER the right thing to-do while beach detecting. For good and bad target
separation changing the detectors coil to a smaller size this can be a very good alternative. Another detector specification to overcome target masking
is how fast the detector responses to a given target signal, the faster the detector's response the better target signal separation between multiple
targets for a given sweep of the coil.
Saltwater Beaches are heavily used by the public and therefore are considered an ideal place to metal detect. Saltwater beaches are usually
divide into the same three major sections as freshwater beaches:
- dry sand,
- wet sand and
- underwater beach sand.
The Dry Sand portion of the beach can usually be detected by many of the median and higher priced detector models. But just turning on the detector
and going for it will not always work, therefore, the detectorist needs to know their detector's capability and adjust it for correct operate at the beach.
Wet Sand detecting on a saltwater beach requires a detector designed to handle high concentrates of mineralization, black sand, all of which is
mixed with saltwater. This type of detecting environment limits the number of detectors available. The detectors for use in this situation will
frequently cost more than $1,000 in price.
Underwater saltwater detecting has the same requirements as a saltwater wet sand detector in addition it must be completely waterproof.
The major challenges on a saltwater beach that a multi-function detector must overcome:
The greatest challenge to detecting a saltwater beach is the sand mineralization, black sand deposits and the saltwater itself. All of these
components are conductive and will influence the detectors capabilities to operate correctly. These conditions cause many detectors to not ground
balance and give false target signals due to the conductivity of the sand's mineralization content and saltwater.
Trash tends not to be a dominate factor for saltwater beach detecting. This is because there is a yearly beach cycle that takes place on a saltwater
beach where in the winter months storm surf and swell action removes sand from the beach and along with the sand the trash is also removed. Another
factor is the rapid decomposition of metallic materials on saltwater beaches. This decomposition is accelerated by the highly corrosive beach environment.
The depth of the sand can also be a factor on saltwater beaches. Saltwater
beach sand can have a depth of may feet and this along with the corrosive
and conductive sands can challenge most detecting equipment.
Must have features in a multi-function detector -
- waterproof to some depth level,
- capability to operate in a saltwater environment (no false target signals),
- coil interchangeability is extremely important to gain coverage & depth (large coils: 10", 112", 15", etc),
- tone I.D. and / or optional digital display I.D. capability.
Want to have features in a multi-function detector -
- very good target discrimination adjustment capability,
- light weight and ergonomically comfortable for the user,
- ground balance capability.
In summary if a detector works well in a saltwater environment it will be very compatible for most freshwater beach detecting
providing the beach is
light in trash. There is a tendency to use larger coils on a saltwater beach (10", 12", 15" and larger) since trash is not a dominate challenge to
saltwater beach detecting. Larger coils also provide for greater coverage and depth. Rapid detector response is not required on a saltwater beach.
PI (Pulse Induction) Detectors generally have the capability to ignore high mineralization beach environments while providing good sensitivity to most
metallic targets. Performance is usually consistent on any type of beach but there are exceptions. When a beach has a very high concentration of black
sand deposits, adjustments may be required even on a PI detector.
The PI detectors designed today have many different capabilities and features between the different manufacture models such as: ferrous and
non-ferrous discrimination (two tone ID), ground balance, dual frequency operation, coil size and bouncy, pulse delay control, VCO mode, audio
frequency control, ground tracking speed, threshold control, etc.
The basic PI is usually pretty much a turn-on and go detector with just a couple of adjustments and the learning curve is usually very short. Since the basic PI provides only a single
target tone the user only needs to learn how the tone may be slightly altered with different shaped targets.
PI detectors are not a good choice for any type of freshwater beach detecting. The reason is that PI detectors
react to all metallic trash as
well as good targets. Since saltwater beaches have LESS trash (usually) the PI can be a good choice for wet sand and underwater detecting.
In some situations using a (PI) pulse induction detector can be very beneficial and the decision to invest and use a PI is very operator
dependent. There are a number of PIs in the table but no ranking exist since there is a good deal of differences between the various models.
In summary there are some differences between the detector used on freshwater beaches vs. saltwater beaches. The differences can be compared in
the must and wants section for each beach type. There is usually a few hundred dollars more in price making a saltwater beach detector more expensive.
Here is a comparison of the must and want features for a freshwater and saltwater detector.