Originally Posted by shufti
You seem pretty handy at that whole docking business. 12 months into 'big boat' ownership and I'm still not relaxed about docking. Don;t suppose you could do an instructional vid on how to 'walk' a twin sideways?
Piece of cake if your wheels turn inboard, iow the port prop is right hand and the starboard prop is left hand. If they turn outboard
it might still be possible or it might not, depending on wheel
size and pitch
, and rudder
Let's say you are docking starboard side to. You are parallel to your dock
, a boat length off. You don't want to go forward or aft, just sideways to starboard.
Start with your rudders hard left. Come ahead on the port shaft and astern on the starboard shaft at the same time. Start at half throttle and reduce if necessary. You may need more throttle on the reversed starboard screw to keep her from inching ahead, depending on your props. Don't be afraid of your throttles in this maneuver. It requires a bit of power.
Why it works... The port screw is ahead, pushing water
over the port rudder
, thrusting the stern to starboard. The starboard screw is backing, compensating for the ahead thrust of the port, and at the same time pivoting the bow to starboard so that both bow and stern are moving to starboard and the boat is not moving fore or aft. The right hand port screw is turning ahead so it is also helping the boat crab to starboard. The starboard prop, being left hand, in reverse is turning to the right, clockwise, so it, too, is helping to crab the boat to starboard. Setting up the props to turn outward makes the boat pivot more easily, but it makes this maneuver more difficult and on some boats impossible.
Obviously you will have to constantly adjust throttles and rudders to have the desired outcome but hard rudder to the opposite side you wish to go, and at least half throttle on both engines and the engine
toward the desired direction of travel reversed, is a good starting point. Practice this around some derelict pilings before trying this in a crowded marina. With so many things going on at once it is common for a newbie at this to freeze up in a moment of indecision.
On crew boats and supply or utility boats in the oil
patch, this maneuver is done routinely. The first time you see it done you will swear the guy MUST have a bow thruster. With a new guy doing this for the first time, you might see why they got all those tires all around the boat. You might not get it right the first time but as with all other close quarters maneuvering, practice helps.
Before you try this, do it on paper. Draw your boat and the props and rudders. Visualize. See in your mind how it works. Bow falling off? What would happen if you reduce rudder? Bow going in before the stern? What way to turn the wheel
? Wrestle with it in your head
so you got a plan.