Ballast tank
Allowing water into, or discharging it to replace by air, ballast-tanks built into the hull.
A standard viewing device used on a submarine is a periscope.
A periscope.
ASDIC
Sonar is used to detect other vessels or ships/submarines through a tube-like device> Andrea
A hydrometer is a special device used to determine the density of a liquid.
A hydrometer is a special device used to determine the density of a liquid.
A device with an overload protection used to control a motor is an Overload Relay.
This sounds like it's probably the sonar system of a submarine.
A remote control is used to control an electronic device form a distance without wires. It uses infrared or radio frequencies to transmit the data to the device.
Haart is a device in Alaska that takes up 35 acres of land. When the device was first being produced by oil company's it was meant to be used to determine where enemy submarines were located. When the military discovered the potential of the deivice they bought it. Evidence has been shown that haart can be used to control the weather both in the sky's and cause earthquakes, even scarier than that it can be used to control the mind. Do the reaserch your self
The thermometer.