Mitsubishi Heavy Industries has a long history in the development of Gyro’s for stabilisation purposes. From 1981 to 1987 MHI developed a gyro for space station stabilisation.  This system obviously had to be built to very high standards and be very reliable. The previous developments and the results of the studies resulted in the development of a robust and reliable passive design. The marine products are marketed under the brand Tohmei.
The Tohmei Anti Rolling Gyro stabiliser (ARG) is a passive gyro stabiliser system based on simplicity with no high-pressure water and hydraulic hose systems, and with no computer controls. Their passive control does not require an electric control unit, resulting in few failures and a high level of safety. Also, the passive system does not require any regular maintenance other than visual inspections from time to time.
Of all the gyros they are probably the least complicated and have an excellent reputation for performance, robustness and durability. The ARG is designed to cool itself with air flow in the unit generated by a spinning flywheel. There are no external water hook-ups, no hi-pressure oil lines and no exposed moving parts making it safer and more reliable for everyday use.
The ARG starts with the flick of a switch and works efficiently at trolling and zero speeds.
Tohmei have a five-models line up with the ARG50T (DC Powered)and ARG65T (AC Powered) for smaller vessels to 10 tons displacement. The three larger models, ARG175T (17500 Nm of torque), ARG250T (25000 Nm of torque) and the top of the line ARG375T (37500 Nm of torque) are all AC only and destined for larger motor vessels. Multiple units can be installed where more anti-rolling torque is required than a single unit can provide.
Auckland based Motor Yacht Service Centre have installed more than a dozen Tohmei gyro’s in vessels ranging from 48’ to 72’.
