200242 Automated Controls

Automated Controls
Report No. 200242

I recently received the following from a friend who is still actively piloting. He requests that I do not divulge the pilotage area. I think it is an interesting report. Aside from the question concerning the rudder, I can remember similar problems with automated engine condition monitors and controllers that could not be over-ridden manually. Specifically one ship I was in suffered several shut downs at critical times because of a low lube oil alarm. The report runs as follows:

Recently we have had two incidents involving fully automated vessels. Both vessels were tankers, new buildings (2000-2001) with a fully computerised engine management system and Becker rudder type. The engines are diesel-electric and apparently the computer cannot be manually overridden. The engine control system does not permit the RPM to immediately follow the telegraph orders, meaning that the telegraph could be put from dead slow ahead to full ahead and the RPM will rise slowly depending on the fuel-economy oriented engine management program. Engine response seems to be extremely slow and the vessels do not seem to handle normally according to their type/class.

The rudder angle goes up to 70 degrees (port and starboard) and we have not been provided with the stalling speed/angle for this type of rudder. The masters claim there is no stalling angle at any speed. Both accidents occurred under good weather conditions and during daylight hours. Both vessels were started swinging to make a turn while decreasing speed. In both cases the swing could not be checked even with full-over opposite rudder and a call for full ahead on the engines. No bank suction/cushion was involved and no machinery malfunction is suspected."

I believe the real problem in the situation my friend outlined is not necessarily the Becker Rudder but rather in the fact that the engine response in computer controlled fuel-economy oriented engine management programs is slow. As ship handlers we are accustomed to "pop" the engines ahead in short bursts to increase rudder effectiveness. For this to happen the RPM speed must exceed the speed through the water. The bigger the difference the greater the effect. Not having this effect available as a tool greatly increases the difficulty in close quarter, slow speed manoeuvring. Some control systems have a manual over-ride mode that can be activated when manoeuvring that allows the engine to speed up regardless of fuel economy. This feature is, I suppose, more expensive. Imagine trying to enter a busy highway if your car would accelerate only at a rate consistent with maximum fuel economy. Just another case where conditions aboard ship are set to satisfy the pencil pushers and not the seafarers.

Have you had any similar experiences with automated engine control. If so please send in details