Docking A Twin Engine Boat

POPS PLAYPEN

Cadet
Joined
Jun 4, 2007
Messages
22
I have a twin engine 33 ft boat, just purchased. I am looking for the best driving techniques for docking her. Some suggest using only the forward and reverse gears of each engine to manuver the boat without turning the steering wheel. Makes some sense to me, but old habits are hard to break. Anyone have any thoughts?
 

erikgreen

Captain
Joined
Jan 8, 2007
Messages
3,105
Re: Docking A Twin Engine Boat

The major maneuvering benefit of a twin engine boat is the ability to drive without using the rudders. Practice it, once you're good at it you'll be able to turn the boat 360 degrees in its own length, dock backward, and pull all sorts of tricks you'd need a bow thruster or an IPS drive for otherwise.

Definitely, definitely learn to drive with two screws.

Erik
 

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
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51,019
Re: Docking A Twin Engine Boat

1st question, outboards, inboard outboards, or full inboard? makes a big difference. as they all control differently.

1st rule is speed. do not approach something faster than you want to hit it. boats do not have brakes, do not count on reverse as a brake.
 

torcano

Chief Petty Officer
Joined
Feb 15, 2008
Messages
423
Re: Docking A Twin Engine Boat

Tasahadaaddy, how is the technique different between I/O and straight inboards?
 

tashasdaddy

Honorary Moderator Emeritus
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Nov 11, 2005
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51,019
Re: Docking A Twin Engine Boat

inboards have straight thrust, and uses the rudder to steer, in reverse it is very inefficient. i/o's and outboards can have a directional thrust, as you turn the wheel.
 

gsyfishy

Petty Officer 2nd Class
Joined
Apr 25, 2008
Messages
173
Re: Docking A Twin Engine Boat

To answer your question, the center of propulsion makes a huge difference, on a straight inboard the propulsion is closer to the center of the boat. If you put one in foward and the other in reverse, you will turn in a closer circle than with an i/o or outboard, this being due to the fact that these motors are to one end of the vessel.
You should use the gears to manuver any vessel with twin motors, and only use the throttle when wind and other circumstances not forseen come into play.
 

torcano

Chief Petty Officer
Joined
Feb 15, 2008
Messages
423
Re: Docking A Twin Engine Boat

Gsyfishy, I assume when you say 'use the gears" to manuver the boat you mean keep the throttle at idle speed. The I/Os have the gears and throttle incorporated into the same control unlike true inboard twins. I am moving up from a single I/O to twin I/Os. I understand you should keep the steering wheel in the center position when using the twin props to control the boat. Is there a particular technique that works best when backing into a slip? For example, if I am backing in and want the stern to go towards starboard should I put the starboard engine in neutral and port in reverse? The other option is starboard forward, port reverse but I assume this will rotate the stern towards starboard in place but not go backwards. I guess the final option is using the later technique to line the stern up and put both motors in reverse to back in. I should have my new boat this week so that I will start practicing but knowing a strategy in advance might help.
Thanks
 

jay_merrill

Vice Admiral
Joined
Dec 5, 2007
Messages
5,653
Re: Docking A Twin Engine Boat

When manuevering a twin engine boat with use of forward/reverse on the two engines, remember that the boat will tend to rotate around the props. Think of a transverse line through the boat, in the location of the props, as a "fulcrum" or pivot point.

Use of differential power this way will move the bow of the boat, more than the stern (especially with outboards & I/Os), unless you have the bow tied off to the dock. For example, if you need to "parallel park" the boat along a dock to the port side, you can nose the boat in at an angle, take a turn around a cleat or post on the dock with a line, and then shift the port engine into forward and the starboard engine into reverse. That will swing the stern of the boat into the spot. As you do this, the bow of the boat will need to come off of the dock a bit, so be ready to provide some slack in the line.
 

arks

Lieutenant Commander
Joined
Nov 7, 2002
Messages
1,929
Re: Docking A Twin Engine Boat

I'm talkin' straight-shaft inboards here.... but when I was learning, one of the best tips I got was to forget the wheel and picture the shifters as a pair of parenthesis- like this: ( ). The shifters will move the boat in that direction (example- port shifter forward, boat moves forward and right). This assumes no other forces are present (wind/ current) but it works for me 90% of the time.
For most recreatonal inboard vessels the rudders are too small to influence the boat's motion significantly at idle speeds, BUT steering can be a useful docking tool with more advanced training. Remember that rudders only work when water is flowing past them.
 
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