The key thing to remember is that for your rudders to work, you need water flow. Not enough speed, no flow, no steering. How much speed you need dedans on th size of the rudders.
No twin inboard will be able to turn to the side of the only working engine from a dead stop. Some will start turning after on boat length, two boat length or more. So the key is to accelerate quickly enough to gain steering.
Ex. Let say your port engine is dead. And you need to turn to stbd from a dead stop.out the rudders hard over to stbd, engage stbd tranny with enough rpm to gain. Speed quickly but without making the boat turn to port. As soon as you get enough speed you will see the bow fall to stbd.
Practice in open waters to get a feel for the best rpm.
Another trick Is to switch the the remaining engine to Neutral in the turn so the thrust doesn't fight the rudders. Obviously you need some speed and momentum for that. So I f you need o make a 90 deg turn to stbd on your stbd engine only, plan ahead, get some speed, rudders hard overnight to stbd and put stbd in Neutral. Then as you have almost completed the turn, put it back I need gear.
The key to single engine handling is to manage your momentum.
In most cases you ll be better off get In the slip bow in using the techniques above. If you really have to back in, again assuming port is dead, put the rudders hard over to port. Start backin in with stbd engine, stern will pull to port. Apply a short burst of power to kick the stern using water flow against the rudder. Strong enough to be effective, short enough not to completely stop the boat... reverse again and repeat.
That's the theory... add some wind and all bets are off.
