Making the boat go sideways without thrusters?

[hromberg]

So I'm new to driving boats with twin engines and the common wisdom seems to be that you center the rudders and leave steer only with the engines to dock and undock. I'm used to driving single screw with rudder though, so if I want to turn around in a boat length without any real forward speed, I just use the prop walk to push the stern (to port on my sailboat) and when she starts making sternway I cancel it out with a blip of forward with the rudder hard to starboard. That pushes the stern more to port. Going back and forth I can pivot the boat in place, but since its a single engine, I can only pivot it to starboard.

How crazy am I to think that you can make a twin engine boat go straight sideways by pushing the stern sideways with prop wash (engine in forward) on one engine, while pulling the bow the same direction with reverse power on the other one? As long as the throttle settings are the same, the boat wouldn't move forward or backward.

Seems to me that if you get the rudder angle correct, left rudder, port forward and starboard back would make the boat go straight to starboard. Right rudder, port back and starboard forward would make the boat go to port.

Am I missing something, stating the obvious, or babbling?

 

[hibanx]

Technically you are correct. In perfect conditions (no wind or current) it is possible and I have seen it done. But with any amount of wind blowing the bow off it is nearly impossible to keep the bow under control. At some point it would require a significant amount of forward throttle to control the bow, which would then have to be matched with enough reverse to keep from making any headway. Pretty soon the entire marina is turned into a washing machine from all of the prop wash. Its not the most elegant maneuver when it gets to that point.

 

[mderlick]

So I'm new to driving boats with twin engines and the common wisdom seems to be that you center the rudders and leave steer only with the engines to dock and undock. I'm used to driving single screw with rudder though, so if I want to turn around in a boat length without any real forward speed, I just use the prop walk to push the stern (to port on my sailboat) and when she starts making sternway I cancel it out with a blip of forward with the rudder hard to starboard. That pushes the stern more to port. Going back and forth I can pivot the boat in place, but since its a single engine, I can only pivot it to starboard.

How crazy am I to think that you can make a twin engine boat go straight sideways by pushing the stern sideways with prop wash (engine in forward) on one engine, while pulling the bow the same direction with reverse power on the other one? As long as the throttle settings are the same, the boat wouldn't move forward or backward.

Seems to me that if you get the rudder angle correct, left rudder, port forward and starboard back would make the boat go straight to starboard. Right rudder, port back and starboard forward would make the boat go to port.

Am I missing something, stating the obvious, or babbling?

1. At dead slow speed, port engine forward stbd engine reverse makes the boat spin in a clockwise direction. Reversing the motors spins the boat in the opposite direction.
2. boat does not respond to rudder unless travelling at a min. speed of at least 3-4 kts., depending on size and displacement. Engines are used for steerage instead, because as we all know, boats have no brakes, and speed in a marina is an invitation to disaster.
3. Using engines alone it is very easy to "parallel park" a twin engine vessel.


Hope this helps

martin

 

[hromberg]

1. At dead slow speed, port engine forward stbd engine reverse makes the boat spin in a clockwise direction. Reversing the motors spins the boat in the opposite direction.
2. boat does not respond to rudder unless travelling at a min. speed of at least 3-4 kts., depending on size and displacement. Engines are used for steerage instead, because as we all know, boats have no brakes, and speed in a marina is an invitation to disaster.
3. Using engines alone it is very easy to "parallel park" a twin engine vessel.


Hope this helps

martin

A rudder with water going over it (whether from boat speed or prop wash) will push the stern in one direction or the other depending on what direction the rudder is turned. How hard depends on the angle of rudder and how much water is moving over it. I've had a lot of folks tell me rudders don't work at zero boat speed, but using the rudder, even when boat speed is zero, is a critical part of maneuvering a single engine boat. It's how you pivot one in place, or push the stern away from the dock (against a spring line) to get out when the wind is pushing you onto the dock. Granted, the rudders on a sail boat are a lot bigger than the ones on a power boat, but the engines move a lot more water.....

Gonna have to go do some fender overboard drills and see how it works this weekend.

 

[hromberg]

Technically you are correct. In perfect conditions (no wind or current) it is possible and I have seen it done. But with any amount of wind blowing the bow off it is nearly impossible to keep the bow under control. At some point it would require a significant amount of forward throttle to control the bow, which would then have to be matched with enough reverse to keep from making any headway. Pretty soon the entire marina is turned into a washing machine from all of the prop wash. Its not the most elegant maneuver when it gets to that point.

That's kind of what I anticipate. I was thinking more about getting off the dock with a breeze pushing the boat back towards it. I figure if the wind is enough to make that not work, maybe it's a good day to stay tied up.

What's the preferred method of getting off a dock in conditions like that? I've seen folks try it and get scraped up and I'd hate to imitate em.

 

[TopHattandTails]

This is a "in theory" it works kind of thing. Hatteras have undeniably "the" smallest rudders on any vessel. That coupled with a keel, make side crabbing difficult under ideal conditions. Instead of running the boat sideways, its a Hatteras - use the rub rail to pivot. Your not gonna hurt anything! The best piece of advise I got when I bought my Hatt was to use "patience" around the docks. Give her some time to react - they are big and heavy. She will go, and it will be a controlled and deliberate gesture if you use patience.

 

[hromberg]

This is a "in theory" it works kind of thing. Hatteras have undeniably "the" smallest rudders on any vessel. That coupled with a keel, make side crabbing difficult under ideal conditions. Instead of running the boat sideways, its a Hatteras - use the rub rail to pivot. Your not gonna hurt anything! The best piece of advise I got when I bought my Hatt was to use "patience" around the docks. Give her some time to react - they are big and heavy. She will go, and it will be a controlled and deliberate gesture if you use patience.

Sounds like very good advice, and it's how I handle my sailboat (a 54' 45000 pound monster with giant rub rails) I get yelled at at the bar frequently by folks that follow my slow stern into the marina at a slow walking speed. All that mass takes a lot to stop it if all you have is a little 64hp Westie to spin the wheel.

 

[Pascal]

Making a boat walk without thruster is a nice exercise which is nearly useless in the real world since in most cases it will not go upwind, even just against 10 kts

Docking up wind,use a spring
Pinned against a dock by wind, use a virtual spring aka your second engine. If you have pilings you don't even need to use fenders, just out the dockside engine in reverse, outside in forward and full rudders toward the dock. Once at a 45degree angle, center the rudders and switch the outside engine in reverse to back out

And yes, use your rudders!! Even at dead slow the prop wash will help and you will pivot around faster

 

[SeaEric]

And yes, use your rudders!! Even at dead slow the prop wash will help and you will pivot around faster

Agreed. I always use the wheel. When you're running a big boat, it makes all the different in the world.

 

[jim rosenthal]

This is a "in theory" it works kind of thing. Hatteras have undeniably "the" smallest rudders on any vessel. That coupled with a keel, make side crabbing difficult under ideal conditions. Instead of running the boat sideways, its a Hatteras - use the rub rail to pivot. Your not gonna hurt anything! The best piece of advise I got when I bought my Hatt was to use "patience" around the docks. Give her some time to react - they are big and heavy. She will go, and it will be a controlled and deliberate gesture if you use patience.

I tried to do this for years. All the books say you can do it, but you need much more rudder area than our boats have. For displacement boats with big rudders, I think you CAN do this, but I practiced for days and days and couldn't get her to do it. The small rudders that we have work very well at planing speeds where you have a large amount of water passing them, to generate side thrust when you turn the rudders. Very large rudders on a planing boat would be great for low-speed maneuvers, but would make way too much rudder action and rudder effort when you were out running. That said, I think at least my boat could stand to have them a bit larger, but it isn't high on my list to change.

 

[dsharp]

They biggest problem with your theory is the engines are too far from centerline and the rudders are hooked together so instead of walking the boat pivots. I have heard that its easier for a boat to walk if the wheels turned inboard but I never really saw much use in the subject to find out. I'll use rudders, throttle, spring lines whatever it takes to land or take off without damage. Sometimes it's just not going to be pretty. The saying goes, " not exactly yacht club but it will do"

 

[carolinacoast]

Any helmsman needs confidence. I still have many more miles and years in sailboats, and love our hatt. I took an afternoon with a well qualified captain as a coach and deckhand and practiced docking in a channel toward crab pots. When finished, I put her back in the slip, stern to the current(paid guys idea) and walked her in with just a spring.

Remember when your sailboat was intimidating to dock? Practice a good site picture, and have fun. It is still just a boat, just more fun for more people.

 

[hromberg]

They biggest problem with your theory is the engines are too far from centerline and the rudders are hooked together so instead of walking the boat pivots. I have heard that its easier for a boat to walk if the wheels turned inboard but I never really saw much use in the subject to find out. I'll use rudders, throttle, spring lines whatever it takes to land or take off without damage. Sometimes it's just not going to be pretty. The saying goes, " not exactly yacht club but it will do"

At zero boat speed, only a rudder with prop wash on it will do anything. If one is in forward and one in reverse, only the rudder behind the forward turning screw exerts any force.

 

[hromberg]

Any helmsman needs confidence. I still have many more miles and years in sailboats, and love our hatt. I took an afternoon with a well qualified captain as a coach and deckhand and practiced docking in a channel toward crab pots. When finished, I put her back in the slip, stern to the current(paid guys idea) and walked her in with just a spring.

Remember when your sailboat was intimidating to dock? Practice a good site picture, and have fun. It is still just a boat, just more fun for more people.

She's still intimidating to dock when there's a current or a strong wind.

 

[Pascal]

Personally I find that current can be helpful as by adjusting the boat angle to the current you can actually easily make it go sideways. Let say you re coming in port side to, current on the bow. If you point the bow 15 to 20 degrees to the dock the current will push on the stbd side and move the boat to port. Just don't let the bow fall off too far works from the stern too.. Adjust the angle with the engines as needed

 

[luckydave215]

I think this ability depends somewhat on the individual boat. ie; it may be easier in a sport fish that has more power and bigger wheels with less windage (especially forward) compared to a motoryacht the same length.
I have had no trouble making my boat go sideways using clutches and rudders, but that being said it's still a confusing cross control skill that takes practice. Plenty of practice.

 

[hromberg]

I think I found a video of someone doing it. I can hear something that sounds like a bow thruster though so I'm not sure. Can't see any prop wash from one.
http://www.youtube.com/watch?v=W36rDKl4T5s

 

[jim rosenthal]

You hear the thruster but you don't see it. Very well done. Even WITH a thruster this isn't easy.

 

[Pascal]

You can hear AND see the grinder! He s got a ton of room, and no current or wind...

 

[34Hatt]

To make a twin engine boat go sideways your appose the rudder to the engine that is in forward.
I have done it in some boats most were 60' or close in length some do it some don't. Many factors involved more than just rudder size. Bottom shape, keel length and depth, wheel size and pitch and other factor we have missed. You just have to try it before you know and most just can't do it.
Theory of it is not enough in the case.