There seems to be a lot of conflicting information out there as to the best method to maneuver and dock a Twin Sterndrive. Many boaters still believe that all twins should be docked like twin inboards. We get this question repeatedly and here is an example from Koenraad in Australia.
Question: "Doug, I'd like to ask a question around manoeuvring a twin sterndrive boat as I keep hearing conflicting information from my boating buddies. My boat's propellers turn towards each other, in other words, one clockwise and the other one anticlockwise. I believe they are Bravo III mercruiser sterndrives. I've been told that given this, I should turn the boat putting one engine forward and the other one in reverse to optimise my turning space. This is obviously a contradiction to your recommendation.
In light of getting a better understanding on this, could you please let me know your thoughts on this? Also, would it make any difference in the way I would park the boat on to a berth or in a marina?" Kind regards, Koenraad.
Koenraad, all twin sterndrives dock easier using my "ARC method". It doesn't matter if the propellers are single and turn both the same direction, whether they are single propellers and turn opposite directions, or whether they are the Bravo III set up with twin counter rotating propellers on each drive. I've tested all three setups and my "ARC method" still outperforms the twin inboard way of maneuvering using one in forward and one in reverse.
Regardless of the propeller setup, the outdrives are still located away out beyond the back of the boat so the leverage to force the boat around is much weaker than twin inboards with the propellers' energy contained under the bottom of the boat. Also, captains never manage to have the wheel perfectly centered - as a result, the twin inboard method is always lopsided.
In the confines of the harbour, but away from the docks, test out my "ARC method", then test the twin inboard method, both on the same windy day. This will answer the question "which is better?".
The twin inboard method will work great as the wind blows the bow down wind, but you'll find that it will never swing the bow back upwind against the wind--but the arc method will, every time.
Many boaters assume that twin sterndrives handle the same as twin inboards.
They have never tried my "ARC method". My "ARC method" has been proven superior every time since the late 1960's when I figured out how to maneuver twin sterndrive houseboats with way more windage and way more drift than cruisers.
The main advantages that I have found with the Mercruiser Bravo III Drives and the Volvo DuoProp Drives, are that they have more bite for faster acceleration, cruising at a lower rpm which saves fuel, and for high speed turns without sucking air.
The Twin Sterndrive Docking Lesson has open water exercises with step-by-step instructions for all three methods of handling a Twin Sterndrive. The best is my "Arc Method". Try all three and you will see for yourself. Using the arc method will give you much more control when maneuvering in tight quarters in a marina and when docking either in a slip or parallel at a dock.
There are much deeper explanations in the Lesson as well.
Thanks for the question. Let me know the results of your test.
A related article on a similar topic: Use the Wheel to dock a Twin?