Minehunters are mine countermeasure vessels that actively detect and destroy individual naval mines. Minesweepers, on the other hand, clears mined areas as a whole, without prior detection of mines. A vessel that combines both of these roles is known as an MCMV, (also for mine countermeasure vessel).
A minehunter uses an imaging sonar to detect and classify targets and then sends out divers or remotely operated vehicles to inspect and neutralise the threat, often using small charges that are detonated remotely.
As the minehunter will often be operating in close proximity to mines, it is so designed to reduce its acoustic and magnetic signatures, two common forms of trigger for mines. For example, they are often soundproofed by mounting machinery on shock absorbers or by using quiet electrical drive and are generally constructed using wood, glass-reinforced plastic (GRP) and non-ferrous metal, or are degaussed, to reduce magnetic signature.
Minehunters are generally small, shallow-draught vessels, as they are often called upon to work in enclosed bodies of water such as shipping channels or harbours. Manoeuvrability in such areas is critical, therefore the Voith-Schneider cycloidal propulsor is commonly used, allowing the engine thrust to be transmitted in any direction. A number of modern vessels use catamaran hulls to provide a large, stable working platform with minimal underwater contact; this both reduces draught whilst lowering acoustic transmission and reducing the fluid pressure generated by the moving hull (mines may incorporate a hydraulic pressure trigger).
