Equipment Guide · Steering Gear
Turn the wheel on the bridge and, far aft over the rudder stock, a hydraulic machine quietly puts tonnes of force on the tiller until the blade matches your order — then stops itself. Tap a step or press "Play" to follow the order from the wheel, down the signal, through the two power units and the rams to the rudder, and back along the feedback link that closes the loop. Then take the simulator: feel the difference between follow-up steering, a single pump, and the NFU lever that never stops the rudder for you.
Loading…
Time it yourself at the pre-departure test: put the rudder hard-over 35° one side, order 35° the other, start the stopwatch — and stop it as the indicator passes 30° on the opposite side. On one power unit that must take no more than 28 seconds; that is 65° of travel at an average of about 2.3°/s. The clock stops at 30°, not 35°, for a good reason: the feedback link strokes the pump back as the rudder approaches the order, so the last few degrees arrive asymptotically and would make the timing meaningless. The auxiliary means of steering has its own gentler figure — 15° to 15° within 60 seconds at half the maximum speed, or 7 knots, whichever is greater. A healthy gear alongside does all of this comfortably; what the rule actually guards is the loaded case at sea — the collision-avoidance swing that must always be there.
In FOLLOW-UP you set an order and the loop swings the rudder to it and stops. In NFU the lever drives the rudder directly — it runs while the lever is over and nothing stops it for you. Watch the swing halve on one pump, and see what happens if you leave the NFU lever latched a few seconds too long at speed.
Limits — hard-over ±35° · slew rate: one pump ≈ 2.3, both ≈ 4.6 °/s · in NFU, release ≠ return — letting go only stops the swing where it is.
The rudder chases the ordered angle at the slew rate the running pumps can give — note how the swing tapers as it closes the order: that is the feedback stroking the pump back to zero. The ship answers the rudder with a rate of turn that grows with rudder angle and speed. In NFU the loop is gone: the lever runs the rudder, the release only stops it, and at speed a forgotten lever puts you at hard-over with the ship swinging hard.
Press Start to take the wheel — order some rudder in follow-up, drop to one pump, then try NFU and leave the lever over a few seconds too long at speed.
Working principle — explained in our own plain words with our own schematic from general marine knowledge (not copied from any OEM manual). Conceptual; varies by ship/model. Reviewed and verified by a Master Mariner.