Walking a Boat

[Tony B]

I am not familiar with small boat so please excuse me if I am explaing what might be the obvious.

I have operated only single engine small boats. I have operated larger 100' to 150' boats with anywhere from 2 to 6 engines and*drives. On the commercial 100 - 150' footers, 'walking' the boat is an everyday occurance expecially when* docking or loading/offloading cargo. "Walking' is commonly referrred to as the maneuver in which you make the boat move sideways. Do trawlers in the 40' range walk? and if they do, do they do it well?

Thanks in advance.

 

[Egregious]

I did it today, but I have twin screws.* Backing up with some sternway if you kick one screw into forward it will move the stern away.* Talk to the sailors, they are very good at driving in shallow water and getting one screw to work in their favor.* Seeing a sailboat back into*a slip is a thing of beauty.

 

[Marin]

You can walk a boat like ours sideways quite easily. What you cannot do is make the boat go straight sideways, as though it had both bow and stern thrusters. I've met people who told me you can, but when I have asked them their technique and then tried it--- and in a couple of instances had them on the boat to "show" me--- it doesn't work. At least not with our boat, which has its props and rudders quite close to the centerline. The spade rudders on a twin-engine GB are actually quite large and effective but there is no combination of rudder, thrust, and power that can make the boat slide directly sideways. You can, however, walk it in if you want, bow in, then stern in, then bow in, and so on.

I never use this technique, however, as our boat responds so well to opposed thrust and the resulting strong propwalk (four bladed props are a major help here) that we almost always come in diagonally until the bow is a foot or so from the dock and then swing the sterns smartly over against the dock with the rudders and opposing thrust (and power if necessary). It is a much faster maneuver than walking the boat it so you are exposed to adverse an adverse current or wind for much less time.

 

[FF]

Single screw is simply aimed at the "spot" at a 30deg angle , and the reverse prop walk will take the stern in easily .

 

[Tony B]

The maneuver I was refering to is when you have counter rotating props. Say for instance you want to 'walk' your boat to port, you would turn you wheel all the way to starboard. Then you put the stbd engine in forward and the port engine in reverse at the same time. The boat will be under a lot of stress and vibrate like there is no tomorrow and the boat will slowly "walk" sideways to port. That is the maneuver I was referring to.
Basically, you are setting your shifters to a pivoting position and setting the rudder for the opposite direction.
So, will this work on a trawler?

 

[psneeld]

I guess the best answer would be ....depends.* Doesn't work with every boat whether trawler or commercial.* It's too dependent on hull shape which helps determine pivot point and wheel/rudder size (plus max angle).

I would say the average twin I've run would be at best a willow leaf technique where the boat goes sideways but there is some fore/aft movement with it.

The smaller (under 60 foot tugs) I have driven are wildly different especially the ones with flanking rudders.* They have incredible manueverability but a straight sidesways walk is an elusive thing in my experience...especially as I said for most recreational craft.

*


-- Edited by psneeld on Monday 21st of November 2011 06:58:05 AM

 

[Sailor of Fortune]

this manuever is a thing of beauty when executed properly. Some momentum, either ahead or astern is usually required. Begginers want to do it from a standstill, and the effort usually falls short-vibrations and overworking of the engines and gears. inboard turning wheeled vessels are usually more responsive. If you twist with the turn and then shift your rudder, it helps immensly,i.e for a port "walk" you would come ahead on the stbd eng, back the port with slight port helm and then shift your rudder to stbd. the balance is keeping it going towards desired direction. the momentum is the key.

 

[Tony B]

It is relatively easy to perform on the 4 to 6 engine Crew Boats. Most Crew Boats are aluminum and relatively light for their size and way over powered.
It works OK on the 2 engine Utility Boats but it is a fight. The Utility Boats are steel and usually have smaller engines and only two of them. Way underpowered.

When walking a boat it feels and sounds like it will shake itself to death. And yes, there is some forward and backward motion but not very much. General maneuvering when in critical conditions like unloading large heavy cargo in 6 - 8 foot seas onto a platform with a crane boom as high as 200' over your head, things can get tricky to say the least. In the relatively recent world in the Gulf of Mex, most cargo loading and off-loading is stopped at more than 4 ft seas. The operative word being "most". These operations would be almost impossible without the ability to 'walk'.
Anyway, I was just wondering if it could be done effectively on a trawler.

 

[Phil Fill]

I can almost walk the Eagle, single engine, straight side ways to port easier than starboard because of the port prop walk in reverse and using the bow thruster of course.* Is that cheating?**

***I can almost thrust the stern straight sideways to port with very little forward motion then reverse to continue the stern to port with the port prop walk, while having the bow thrust on.**

 

[koliver]

Works fine on my boat, with relatively large rudders, twins, 3 blade props. I do it all the time to get the bow into my shelter without touching the pads on the side supports. The key is to set the wheel and leave it alone, using only the throttles, at low rpm. patience.
Doesn't work well in over 5knots of breeze, nor can it overcome much current.

 

[Tony B]

koliver wrote:
...... The key is to set the wheel and leave it alone, using only the throttles, at low rpm. patience........

*Truer words were never spoken. When I first started running crew boats, that was the first thing I learned. If you work the wheel you will work yourself to death.

The next thing I had to learn was to see how slow I could dock a boat. If you approach too quickly and have to back down quickly your prop wash gives the boat a personality of it's own. Every correction leads to another correction.

 

[Tidahapah]

Those days are over in the oil world down under.
All Oil companies require either dedicated AHTS or PSV vessels and it is either DP or at a minimum azimuth prop.
Even then we get restricted to 4 mt (13 ft) swell /wave height and 30 knots wind unless it is absolutely critical.
Vessel to vessel personel transfers are virtually unheard of these days , that is nearly all chopper work except in extreme cases.

 

[Jay N]

In my former life, I had an opportunity to maneuver twin screw tugs from 45 to 125'.* As others have noted, some fore or aft motion can be very helpful.

But the ability to walk seems to also depend a great deal on hull design, distance between the screws relative to beam, and propulsion configuration.* For example, a propeller housed in a nozzle just doesn't respond well.

The best tug we had for walking was a 72' open wheel twin screw design with a relatively wide distance between the props.* And while it walked the best, it was not used/needed for precision positioning so the effort to walk just ended up being a waste of fuel.

The most efficient maneuver with a twin screw vessel is treating it like a single screw and using the twins to only maneuver*the stern during the last/first few feet.


-- Edited by Jay N on Monday 21st of November 2011 10:39:46 PM

 

[Marin]

Jay N wrote:
The most efficient maneuver with a twin screw vessel is treating it like a single screw and using the twins to only maneuver*the stern during the last/first few feet.

*I certainly agree with that statement.* It's how we've learned to*operate our boat.

BTW, the boaters I truly wonder about are the ones who, regardless if they're single or twins, "drive" their boats with the bow thruster.* Our slip has a view of the north entrance to our marina basin so we can watch all the traffic coming in and then making the turn around the fuel dock and on into the docks and slips that are farther into the basin.* Given that most bow thrusters sound like putting steel bolts into a Cuisinart it's hard to ignore the sound so we almost always look up to see what's happening.

If I had a buck for every boat, from little things like 34'*Nordic Tugs to big 50 and 60 footers, who use their bow thruster to make every heading change as they come into the marina and turn into their dock and then their slip, I could pay cash for that Fleming 55 we want.

And we're not talking about a set of super-narrow fairways here.* They are quite wide, enough to do a 360 with a big boat using rudder alone and have plenty of room left over.* Yet these people are on the thruster all the way from the breakwater entrance to their slip.* I doubt they ever turn the wheel at all.*

I guess a lot of boaters can't grasp the notion that you steer a boat by moving the stern.* They need to have it respond like a car.* They even use the thruster to change their headings*slightly*when meeting another boat on the way in or out.* And then they use the thruster to get back onto the heading they had after they've passed the other boat.


-- Edited by Marin on Monday 21st of November 2011 10:58:06 PM

 

[markpierce]

Umm, takes some nerve to criticize someone with a bow thruster and a single screw*when one has twin screws.

 

[Marin]

Read what I wrote. I'm not talking about using a bow thruster to maneuver into and out of dock or slip. I'm talking about people who drive their boats around using the thruster instead of the rudder. In other words, instead of turning the wheel and thence the rudder to make a turn in the channel or fairway, they use the thruster even when traveling at 4 or 5 knots. To me, this is just about the epitomy of ignorant boat handling. And I see as many if not more twin-engine"skippers" doing this as I do the drivers of single engine boats (yes, Martha, there are a lot of twin engine boats around with bow thrusters).


-- Edited by Marin on Tuesday 22nd of November 2011 01:13:29 AM

 

[markpierce]

Made a wrong turn to the fuel dock today.* And it was a lot easier to spin around to the proper direction using primarily the thruster (as well as the rudder) within the confines of the marina.* I'll not apologize for my actions.

 

[GarryP]

I've "shuffled" our Manatee sideways - single screw and bow thruster. By shuffle, I mean there was a little forward and back motion but the overall direction was sideways.

 

[FF]

"Made a wrong turn to the fuel dock today. And it was a lot easier to spin around to the proper direction using primarily the thruster (as well as the rudder) within the confines of the marina."

The hard part is nor exceding the very operating limited time of most electric thrusters.

 

[Marin]

markpierce wrote:
Made a wrong turn to the fuel dock today.* And it was a lot easier to spin around to the proper direction using primarily the thruster (as well as the rudder) within the confines of the marina.* I'll not apologize for my actions.

*Well you're obviously the world's worst boat handler if you had to do that

If you need to use your bow thruster, use it.* That's what it's there for.* Although* you could have accomplished exactly the same thing using your propeller, rudder, and inertia alone.

It's the people who use the thruster in lieu of the rudder all the time even in open water that are the true bozos in my book.

 

[skipperdude]

I thought this was about throwing someone a line when the wind is up and have them walk your boat to the slip. like a dog on a leash

Shows what I know.

I have had my boat walked many a time.

sure makes it easy to dock.

SD


-- Edited by skipperdude on Tuesday 22nd of November 2011 01:57:10 PM

 

[markpierce]

skipperdude wrote:
I thought this was about throwing someone a line when the wind is up and have them walk your boat to the slip. like a dog on a leash

*I admit that was the first image that came to mind.

Mark, Senior Dufus

 

[psneeld]

It's OK Mark...that's what thrusters are for.....make life easier and possibly more enjoyable.....just like second engines..

-- Edited by psneeld on Tuesday 22nd of November 2011 07:21:57 PM

 

[markpierce]

Marin wrote:
It's the people who use the thruster in lieu of the rudder all the time even in open water that are the true bozos in my book.

*No disagreement here.

The longest time I've used the thruster was to make a 200-degree turn in the marina: about two four-second bursts.* When docking it might be three or four half-second bursts.* Managed without*the thruster*(sometimes clumsily) for several months when*it wasn't working.