Description
Object description
A Royal Navy colour film looking at different aspects of undersea warfare, incorporating lots of shots under water. The film includes sea mines, ship's divers, clearance divers, patrol submarines, nuclear submarines and anti-submarine warfare.
Content description
Commentary explains that ‘the undersea war is a war of stealth and patience’, while footage varies from the crest of surface waves to shots deep underwater. The peculiarities of conflict in this marine environment are outlined, and the ways in which challenges very specific to ‘undersea war’ can be overcome, by technology and by knowledge.
The operational mechanism of mines at sea is explained in detail, culminating in the dramatic moment of detonation. The process of sweeping for buoyant mines is outlined. Once on the surface, they can be disposed of with well-aimed armour piercing bullets. Focus then turns to how to deal with influence mines. Vessels and the working procedures of crews at sea are featured; two men in a speedboat make a quick getaway, after they blow up a mine on the seafloor.
The important roles of the diver and the clearance diver are explored, with underwater footage of divers at work, including routine searches of the keel. A lively sequence set to musical soundtrack shows the training of clearance divers at Portsmouth, Horsea; dubbed ‘Devil’s Island’. This physically demanding training is no 'holiday camp’ and includes stamina building activities like crawling through Horsea mud, as well as swimming, and diving from a height into water. Training in deep dives is done at sea.
The depths and vastness of the sea can be useful for defence, since it offers a chance to hide. Internal and exterior shots of a patrol submarine are followed by those of submariners at work, using a periscope and sonar. Once a submarine fires on a target, commentary explains, its greatest asset of secrecy has been spent, and so it becomes imperative to hide in the ocean. The aim is to prevent the hunter becoming the hunted, to try to evade radar. Underwater sounds, natural and manmade, are featured; ‘the silence of the deep is a myth’. The skill of the sonar operator is celebrated and the technology showcased.
Interaction ensues between sonar operators, operations room and a helicopter pilot, when trying to guide a Wasp helicopter to locate a submarine at medium range and fire on it with a homing torpedo. This form of attack is known as MATCH [Medium-range Anti-submarine Torpedo Carrying Helicopter].
To deliver a torpedo at even greater ranges than a MATCH attack, a Wessex helicopter sets off from an aircraft carrier and takes its own sonar set with it. Operations over water are shown, as the Wessex moves from one location to another, imitating ‘grasshopper antics’ in an attempt to detect a submarine, before launching an attack.
When trying to detect a submarine at medium ranges, ‘the best weapon’ against the sea is 'greater knowledge’ and applied technological advantage. A Bathythermograph, a variable depth sonar and the Mk.10 Mortar are briefly shown in operation.
Commentary concludes that ‘The most deadly submarine killer is one of it’s own kind’ - the fleet submarine, nuclear-powered - before summarising the variety of weapons, systems and people who can be employed to gain the advantage in the 'undersea war'.
Physical description
16mm