Hello everyone and welcome back to part two of the naval mines topic.
In this video we will be examining the different types of mines and how they function. If you
missed the first part of this video I recommend checking that out either now or after you watch
this as it will walk you through the historical usage of naval mines through different conflicts.
If you’ve already seen that part then please sit back and enjoy the rest of this video.
As we discussed last time, mines come in many forms, one type that can be technically considered
a mine are limpet mines, which operate by being magnetically attached to a ship and
triggered by a fuse. They are called limpet mines due to them being stuck onto something,
just like the aquatic snail they got their name from. These mines are usually deployed
by combat swimmers or small submarines, and are used in covert operations as a device that can
be easily attached to a target and detonated without the enemy being aware of its presence.
Limpet mines have been used throughout the 20th century, most notably by Allied and
Italian frogmen during WWII. Due to these devices commonly being referred to as mines, and the fact
that they operate by being magnetically attached to a target, it can be said that this is likely
the reason that the misconception of naval mines attaching to their targets is common.
The simplest and most well known type of mine is the contact, which has been extensively used
throughout history. As described earlier, these mines require a ship to make direct
contact with the mine. Detonation is triggered by different mechanisms, but the most common
is the reliable Hertz horn type. These can be set in different ways, with the most common
being those that are moored in some way. This is through the usage of an anchor or a plummet,
which are pre-set for their targets: for larger targets, the cables would be shortened so that
the mine would float at a deeper depth so that they did not make contact with smaller ships.
There were also some that were allowed to drift around in the ocean without any form of anchoring,
and these drift mines were much more dangerous due to them being able to hit
any type of ship - civilian or military. While contact mines were armed with standard explosives,
there were tests in the Cold War to use nuclear mines but were never actually produced.
The other most common form of mine is that which is triggered not by a ship hitting them,
but rather a ship merely being near the mine. These are often magnetic mines, but also include
those that use acoustics or pressure to detect a ship. While these mines include the term
“magnetic,” they do not stick to ships but rather work to detect the reaction between metals in
ships and the Earth’s magnetic field. When a ship passed over one of these mines, the metal would
react with the magnetic field and effectively drag the field towards it. When this happens,
the mine would detect that the electrical field has changed and the mechanism would
trigger a detonation. Eventually modifications would be added that would delay the detonation,
and only react to changes that were more sustained in order to combat minesweeping
and degaussing activities. One of these modifications were known as
total field magnetometers and measured the total background electrical field surrounding the mine
rather than just the field of a possible target so that any change would be detected.
Modern magnetic mines follow these same concepts, but with more advanced magnetometers and sensors.
Acoustic mines on the other hand are those that react to specific sounds that originate from
the movement of a ship. There are two types of acoustic mines, active and passive; passive being
the type first used in early WWII, and relied on the usage of a hydrophone in order to trigger the
mechanism. The way that these worked is similar to the way a speaker functions. A thin sheet of
material would flex from vibrations, this is called the diaphragm, and in the mine it would
essentially do the same thing - but instead, reacting to the sounds produced by a ship. The
moving of the diaphragm would then cause a switch attached to it to close, and send an electrical
flow towards the detonator. Funnily enough, the British found that a jackhammer produced
the sound necessary to detonate early German mines and would use them during minesweeping.
Further developments saw the ability to “tune” the hydrophones towards the sounds of different
ship sizes, such as a battleship’s deeper pitch. Modern hydrophones allow mines to be even more
precise when it comes to detecting a specific sound. An active type in contrast is one that
sends out pulses that reflect off of a ship and tell the mine how far the target is away.
Pressure sensing mines are another type, but these react to the changes in pressure caused
by the movement of a ship. The pressure for which it detects is created by the displacement
of the water around the ship, with a larger ship causing more pressure to be generated.
Often, the mine will detect the difference between the pressure of the bow and stern of a ship and
detonate accordingly. The problem with these mines is that they are easily affected by waves,
and can often be tricked by the action of a wave on the surface that may be similar to its target.
Because of issues like this, modern influence mines are designed to use all three types of
sensors so that they are not prematurely triggered by minesweeping action or natural occurrences.
While magnetic and other influence types of mines do not act to physically move towards a target,
the Cold War saw the creation of mines that actively target ships. These are called homing
mines, and they work exactly as the name implies as they are armed with devices such as torpedoes
or rockets. These are used to engage ships such as submarines, as they can be deployed at significant
depths and have a greater chance of hits. One of these is the Mark 60 CAPTOR developed by the US,
which is a torpedo placed in a capsule that allows it to be able to moor to the seafloor
and wait for its target. Once one is detected, it will release the torpedo and track the ship.
The history of the naval mine has seen the weapon evolve from primitive boxes
allowed to float on the surface, to more complex machines that are able to detect
aspects like the change of the Earth’s magnetic field from a ship.
From a weapon shunned by many western navies they have become a major part of naval strategy. This
is due to the relative cheapness of mines, as they can be mass produced for a low cost
but potentially eliminate highly valuable enemy targets with little to no harm to friendly forces.
With this potential in mind and the continued development of more unique mine designs,
it is likely that these infernal machines will remain a battlefield danger for years to come.
Thank you all for watching and I hope you enjoyed the video. A special thanks once
again to Baron Von Teapot for helping out with the research and script for this video
as well as to all my channel members for helping support this content. One last reminder to
check out part 1 of this video if you haven't already and I will see you in the next video.