I'm not talking about inboard or
outboard or inboard / outboard
engine installations. This is specifically about which direction counter-rotating propellers turn in relation to each-other when going forward.
If you walk around any boatyard you'll notice that about 99.9% of all twin screw, counter-rotating
propulsion systems are set-up to turn "outboard" when going forward.
As viewed from behind the boat, when going forward, the stbd prop turns clockwise (right) and the port prop turns counter-clockwise (left) and is referred to as "outboard turning props".
"Inboard turning props" turn, as viewed from behind the boat, when going forward, the stbd prop turns counter-clockwise (left) and the port prop turns clockwise (right).
In other words... the
tops of the props are turning toward each-other (inboard) instead of away from each-other, when going forward.
I don't own a sailing
catamaran but I am a working relief
captain on three different ones (52 - 60 ft) doing day trips & sunsets around St Thomas & St John... all if which have outboard turning props. They turn on a dime but will not "walk" when
docking. I've worked on only two vessels in my career which were set-up with inboard turning props (one was a
power cat) and I remain amaized at the superior handling characteristics they had simply because their propulsion systems were set-up a little differently.
All I'm trying to say is this is something my twin-hulled brothers & sisters should consider. It would require very little cost or effort to simply change the props to the opposite engines and fiddle with the shifter linkage. Once you've gotten the feel of it you'll certainly be impressed with the difference in ease of handling.
And that's all I have to say about that.
Kirk