From the little boat angle, the sweetest walkers were the twin screw lifeboats on the NCL Pride of America. I was cox’n of one in 2004. The screws were spaced wide and I don’t recall if they were inboard or outboard, but using A she walked like a Disneyland ride on a straight rail.
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That is a good way to visualize this. My understanding is outboard turning props are more efficient but inboard turning produce more traverse thrust when the boat is being ‘walked’.
Cruise ship lifeboat props are likely inboard turning.
I remember being taught that inboard turning props created more thrust, similar to Cappy’s observations here:
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Yeah, too far into the weeds for me.
I know a single screw ship with a right-handed propeller will walk to port when backed and it’s not a subtle thing.
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I count on that myself, I usually come into the dock with the dock on the port side at an angle, full reverse stops the boat dead and sucks the stern right into the dock 
To add further confusion, kort nozzles negate any transverse thrust from the propellers so the direction of spin is meaningless and they walk horribly as a result.
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When using twin screw for ship handling you have three considerations, torque, transverse thrust and rudder.
Fixed pitch outward turning screws are more efficient for ship handling as transverse thrust works with the screw torque when using one engine ahead and the other astern.
Fixed pitch inward turning are less efficient for ship handling as the transverse thrust works against the screw torque. However inward turning fixed pitch is more efficient for propulsion.
Always use the rudder, by far the biggest force especially if high lift rudders.
I say inward turning fixed pitch is good for accountants but bad for pilots.
Outward turning fixed pitch is good for pilots and bad for accountants.
If you consider “conventional” twin screw ship handling as port engine ahead and starboard engine astern, bow will swing to starboard ( remember always use the rudder).
However you can “walk” a twin screw ship but a better description would be “vectoring “. In this case ship starboard side alongside and wants to lift off berth, no bow thruster. Rudder is put hard to starboard, inboard/starboard engine ahead. This results in the stern lifting but the bow will want to swing to starboard and hit the quay. To counteract this the outboard engine is put astern to counteract the rotation and the ship lifts bodily to port.
This works well with tugs as they are relatively short and fat with props well spaced apart so a lot of torque is produced. However ships are relatively long and skinny ( compared to tugs) so the torque produced whilst not insignificant is not in the same realm as a tug and is not always very successful. It can be done on ships but needs a lot of power if using a standard rudder.
Tug skippers instinctively use “vectoring”, ship Masters and Pilots want to be “conventional”. Each works well in their own area of expertise.
All takes a little thinking about, makes me feel a little cross eyed reading it back!!
For transparency, I am a pilot who teaches at Warsash Academy Ship Handling Centre where we have inward and outward models to play around with. The knowledge I have gained from ex tug skippers/pilots and Masters has been invaluable.
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Interesting observation, I’d never thought of it but it’s generally true.
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There is a trick to docking a single screw ship without a bow tug or thruster. [Edit - when docking starboard side to] If she has a right hand prop you maneuver to a position a ship length or two from the desired position and back toward the berth at an angle. The trick is paying attention to the ship’s pivot point. When moving astern the pivot point acts like it is aft about 3/4 to 4/5 ship length from the bow. When going ahead the pivot point is at the opposite end near the bow. As you back down, the prop will exercise a clockwise force that slightly pulls the stern to port. You might be able to minimize that by backing with rudder hard right. Meanwhile the bow will rotate toward the berth with the bow closing the dock about 4-5 meters for every one meter closure at the stern.
Get a feel for where the ship will land. If it looks like the angle is too shallow and she will back past the position, you need to adjust the angle some toward the dock. With the rudder amidships kick her ahead. As soon as she stops and just begins to get headway put the rudder hard left. The stern will now move toward the dock and the bow will check its swing. When you have the appropriate angle come astern again and continue toward the berth. If you put the rudder over before you have slight headway the stern won’t close the dock much and time will be wasted.
If it looks like you will land short of position the angle is too steep. Do the opposite. Put the engine ahead, wait until she just barely begins to come ahead and put the rudder hard right. She will begin to straighten up. Stern will stay more or less the stationary, bow will swing more quickly.
This is much easier to demonstrate in a bar with napkins.
When I was first taught this at Grenoble the instructors were divided over whether the trick worked for port side docking as well. In real life it does not work both ways. You can do it starboard side to with a right hand prop or port side to with a left hand prop.
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Or use a bow spring line. Works with both inboard and outboard turning prop, going port or stbd. side alongside.
PS> Gets you off the wharf as well.
Yeah, don’t quite see but in general sounds like exploiting the shift in the pivot point to work both ends in.
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I use that trick all the time for getting into a tight space, it works well on either side of the boat. It also works with a midships spring line.
I would wonder how far you can scale that up, if I jump off a tanker with a spring line in hand and put it around a cleat, is the ship going to just keep going and remove the cleat and a section of the dock?
- and yes, I realize that mostly you can’t literally jump off a ship onto the dock usually
Commonly used on smaller single screw ships w/o bow thruster.
How large ships you can do it with?
I have done it with a tanker of 17000 DWT, (620’) but only because there were no other options available.
I have also used this method with an underpowered 370’ Drillship with two Azimuth thrusters aft and no bow thruster. This one:
[Reply to Ombugge] I offered a trick to get you backed into a long slip with a large ship that has a single propeller and no tug or thruster to control the bow. Of course in a straightforward docking a spring line can be used. That is what they teach in Motorboat For Dummies class on the 2nd day. I thought the thread was addressing a more experienced audience.
Why would you need this? If you do enough dockings you are going to have a bow thruster that won’t start or a tug with an engine failure. You still have to get your ship out of the channel for traffic and up the slip to the dock. Can you use the anchor? Sure, if there’s no pipeline, but if you’re backing down a slip the bow stays in the middle. You need to get it close enough to throw a heaving line ashore.
Besides, it just looks so damn elegant to back her down and lay her gently alongside the dock in perfect position without assistance.
[Reply to Ombugge] “How large ships you can do it with?”
At Grenoble they have the ability to set up docks and currents for training. We learned the technique using the models of 250m ships. In the real world they always send plenty of tugs for those guys. I had to do it twice with ships that were around 150m because of bow thruster failure.
Sorry, did I say something that offended you?
Didn’t know you were talking about “a trick to get you backed into a long slip with a large ship”.
I just pointed out that there are a simpler way of getting a single screw ship alongside (or off) a wharf.
Bow spring was a widely used method before bow thrusters became the norm, even for quite large ship and in difficult conditions.
This training centre?:
I did not attended any formal ship handling courses like this, nor “Motorboat For Dummies”.
I had to learn it the hard way, by trial and error.
PS> Back in the 1990s I worked with a fellow that started a similar kind of training center for J/U rig moving in Texas:
Last time I saw a boat get into a tight spot, the skipper just shoved a joystick in the direction he wanted to go and the nice computer did all the steering and throttle work for him. I wonder if some day when DP is on anything bigger than a dinghy if all these techniques will be a vanishing skill.
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Used to be a joke that went; “Giver her a kick to port Mr. Mate”.
Now that is no longer a joke. "just shove the joystick in the direction you want to go " is the norm.
Actually take back the “bigger than a dinghy” thing, there are now DP setups with trolling motors that literally CAN fit on a dinghy!
This has run it’s course and become off the original topic.