Tic
A tic is a sudden, repetitive, nonrhythmic motor movement or vocalization involving discrete muscle groups. Tics can be invisible to the observer, such as abdominal tensing or toe crunching. Common motor and phonic tics are, respectively, eye blinking and throat clearing.
Combimac
In 2005 the development of rim drive thruster motors was initiated. The revolutionary compact lateral thruster was developed by two separate partnerships: Rolls-Royce with Smartmotor from Trondheim and Van der Velden® Marine Systems with Combimac. The electrical permanent magnet motor has the form of a thin ring. Its stator is incorporated in the tunnel and its rotor carries propeller blades. Waterflow through the unit is unobstructed since there is no gearbox in the tunnel, nor are struts needed to support a hub. Together these factors give a high total efficiency and reduced noise and vibration, due to no cavitation as result of a low tip speed of the propeller blades. The prototype was successfully tested at the MARIN (Maritime Research Institute Netherlands) The patented thruster design has won two innovation design prices. The permant magnet motor technology was also implemented for the development of the motor/generators in hybrid drive systems on board super yachts