There are three main reasons for buying twins—better maneuverability, better performance for a larger boat, and assurance that you still have power if one engine quits for whatever reason.
But, what if one quits? You need to know how to handle and dock your twin inboard, twin sterndrive or twin outboard with just one live motor. It’s totally different than docking with both running, and different than docking a single engine boat.
Thanks Rod Brebner for suggesting an article to cover docking with one dead motor. In his case, it was the starboard engine, so he had no power steering.
On a single, the motor is in the center of the transom and the thrust is balanced; whereas, on a twin, the motors are off center. Therefore, when operating a twin with only one motor, the thrust is off center. This creates some differences from handling a single and some challenges to overcome.
If your power steering pump is on your dead motor, you will discover how much work your power steering pump does for you. It will be a real brute to steer. It will be like trying to push a shopping cart with one back wheel seized. It doesn’t maneuver worth a toot.
Another major difference you will notice, is that your turning radius will be greater or much greater depending on your turn direction and which engine is dead.
Murphy’s law usually kicks in when one motor dies. It’s usually the one with the power steering pump on it. So, turning the wheel will be difficult, which changes from you being able to palm it around, to having to use two hands to pull it around. As a result, you want to make each turn count to the maximum to reduce the number of times you have to turn the wheel from hard over to hard over.
I recommend you spend half an hour on a calm evening with one engine shut down and pratice handling and docking your boat; so that you are prepared should you ever be caught in the situation of having a dead engine.
Open Water Exercises
Start in open water. Your first exercise is to do a hard-over turn with your running motor on the outside of the turn. Let’s assume it’s your starboard engine that’s running and; therefore, you’re turning to port. The bow will come around to port in a gradual curve. To tighten this curve, give a short shot of throttle, then pull into neutral and watch it turn tighter as the whole boat tends to rotate or fish tail, as well as continue the curve to port.
You would expect that to tighten this rotation to port even more, you would pull the running (starboard) motor into reverse. On a Twin I/O or a Twin O/B, turning the wheel hard over the other way will help; but, on a twin inboard, when you pull your starboard (outside) engine into reverse, the back end stops swinging and actually reverses against the swing—back on the track just travelled.
The second exercise is to turn against your running motor. Using the same motor as in the previous exercise, our starboard engine is running and we are going to turn hard over to starboard.
You will notice that when it’s in forward, that the boat requires a lot larger radius to turn, because the thrust is on the inside of the turn. When it comes time to approach your dock and turn in a narrow harbour, keep this discovery in mind; so that you allow enough space to negotiate the turn you must make in the harbour.
Exercises three and four are to repeat one and two with the other motor (running) i.e. port.
Once you are comfortable with all four exercises in the open water, repeat all four in the confines of the harbour. Then, when you can do that without problems, it’s time to approach a large gas dock or service dock.
I recommend a large dock as opposed to your own dock, because there should be more space and fewer boats, and maybe even a dock helper. This is a case, where dock helpers may come in handy.
Have lines and fenders ready and your First Mate on the aft corner as described in each of the easy-to-following introductory docking lessons. When it happens for real, call ahead on your VHF or cell phone to have someone from the service department or gas dock catch your line.
Docking with a dead motor is a unique situation that needs to be practised ahead of time. But, as sure as it’s going to rain on your holidays, at some point, you’ll lose a motor and be required to dock with the remaining live motor. Better to be prepared.
For More Information
In each of the Advanced e-Lessons for Twin Inboards, Twin Sterndrives and Twin Outboards, there are detailed instructions on docking with live motor to the dock and docking with the dead motor to the dock; as well as many other neat maneuvers.