Originally Posted by Jim Cate
Ben. I've always wondered: in such ships, when making way, can they stop and restart the engine(s) in reverse, as in the proverbial crash stop to avoid running into something? Seems that t he torque from t he propellers would be hard to overcome...
BTW, I do know that the term "crash stop" is not descriptive when applied to a ship!
No chance. Our ships P&O containers, then P&O Nedlloyd, now incorporated into the Maersk supercompany ran at around 18-19 knots. Nowdays they are comsidered babies (2000-4000 TEU) We couldn't start the engine in reverse until about 6 knots from memory. Even then we occasionally missed, and couldn't get the engine to start (first go at any rate). That got interesting coming into a berth...
The quickest way to pull them up was to put the helm
hard over. In that case our advance (distance ahead ) was typically about 1 Nm and approximately our turning circle was similar.
With a complete engine failure (usually due to a blackout or genset overload) at full sea speed we would run about 7 nm or depending on a lot of factors, being completely NUC with no rudder
all the while, slowly turning one way or another.. Had this happen a few times on the older ships. The newer one ran shaft generators which helped prevent this.
In a true crash stop the engines were best slowed down at a certain rate to prevent the props cavitating, and the rudder
would be fishtailed to slow her down. Probably pull her up in two miles or so, but we never tried it. Certainly the engineering dept would have something nasty to say about the OOW (officer of the watch) in this case! When FAOP (full away on passage) the engine revs are fixed and various economisers and stuff relied on the engine exhaust
gasses to to drive certain engineering stuff. Touching the revs without giving the engineers time (usually 20 mins notice, but I've seen them do it in 10) to start up auxiliary boilers and all the extra stuff was a good way to cause a few pages worth of alarms and a couple of pissed off engineers in the best case.