Docking prop walk

[rslifkin]

So some transmissions rotate the shaft and prop in the direction as the engine crankshaft and some transmissions reverse that direction of rotation? That would explain some of the confusion about which is which.

Correct. With some transmissions like the older Velvet Drives, it depends on the gearing (most ratios on those rotate same as input, but 1 of them is reversed). And many newer transmissions can be operated in either direction (to handle counter-rotating props on twin engine boats without needing 1 engine to rotate backwards). With a transmission that can operate in either direction, it's up to the boat builder to decide which direction they want the prop to rotate and then just hook up the shifter so the correct direction is "forward".

 

[HeadedToTexas]

Ah yes, that makes sense. Twin engine boats create the need for shafts and props to rotate in either direction. Looks like I have single screw bias!

 

[SteveK]

So some transmissions rotate the shaft and prop in the direction as the engine crankshaft and some transmissions reverse that direction of rotation? That would explain some of the confusion about which is which.

Yes, and the reason twins back up straight as prop walk in either direction is balanced, steering can be done by putting one in neutral.

 

[HeadedToTexas]

Roger that.

 

[High Wire]

She is a 2009. Thanks for that information. We will give it a try. You mentioned that the rudder should be straight. I was under the impression that the rudder needed to be hard starboard in order to turn port when in reverse. Looking forward to practicing in calm winds.

The reason I said to keep the rudder centered is to first determine how the prop walk moves your boat. Once you determine the direction, then you can use the rudder any way you want to help you turn or help you stay straight as needed.

 

[alormaria]

If it weren't for prop walk I wouldn't be able to dock at all.

 

[Hippocampus]

This has been one of the hardest things to learn going from a sailboat to single screw trawler.
What has helped is-
Before coming in deciding what to do and sharing that expectation with the admiral. Assess wind and current's to ascertain if either will help or hurt.
Then think how you can get into the slip. Usually it not backing straight in. If you have a RH prop and will walk to port in reverse start a bit to the left of the slip or perpendicular (looking to aft) with the boat lined up somewheres near 45* to straight in to the slip depending upon conditions. Then walk will cause you to line up to slip.
Hardest part is to loose the expectation you will ever back up straight. You need to use the walk for you. You need to learn how much walk you get and at what throttle. On my boat a burst gives a bunch of walk with little motion. Light idle gives less walk.
Have learned to use momentum as well. Once you get the boat moving you can go to neutral and neutral helm and steer with the bow/stern thrusters.
As mentioned above there’s little or no rudder wash at low speeds in reverse. I like to be stern to but have learned to accept sometimes it’s just not possible. Although the stern and bow thrusters are the same HP the bow thruster is much more effective. Rudder wash is much more as well. So bow first is easier.
Last thing I’m not above using a spring. If I can loop a midship boat cleat on a cleat near the end of the dock then backing down pulls the boat in. As a mom and pop then we leave the boat in low idle reverse or small intervals of reverse to keep it against the dock. One of us disembarks safely and sorts out the rest of the lines. This is often necessary in a cross wind over starboard side or a current.
I have a significant keel which helps. Still there’s times I need someone on the dock. I find google earth helps deciding when plus knowing wind and current before hand. With less keel you more frequently may need help.
Love watching people dock. Have learned a lot from that as well as practicing using a bouy as the target.
Still a newbie at this so have no ego and will stop the attempt and leave to make a new approach before hitting things. So far I look terrible but on the other hand have not hurt my or other boats so far.

 

[SteveK]

Going down the fairway and wanting to back in, the preferred berth is on the boat port side. IMO

 

[Marco Flamingo]

Hardest part is to lose the expectation you will ever back up straight.

I always blame this on our much greater familiarity with driving street vehicles. We never have to slowly crab walk the car into a parking spot while factoring in the wind direction. Everybody has seen the captain that gets into a situation where he/she needs to hit the brakes. I haven't seen that accessory available for boats (yet).

For me, patience is the element most responsible for improving docking skills. Having been away from my moorage for hours or days, what matter if docking takes eight minutes? Or requires a correction and do-over? One thought that always gets me to take things slow and easy is the safety of my crew (wife). Last advice before she goes on deck when docking is "no heroics."

An exercise that can help you understand prop wash is to throw a fender out in calm weather. Best if it doesn't have the line attached to it (although there is also a reason to learn with the line on). Practice coming up to it so that a person on the swim step can retrieve it (or use a salmon net). Even better if you travel as a duo is if you can go back and retrieve it. You will quickly learn about prop wash and the way the boat handles when slowing down. One side will quickly become easy, the other side very difficult, but doable with practice. Many moorages have an outside breakwater that says "NO MOORAGE." The perfect place to practice your "touch and go" docking skills. The gas dock after closing is another spot. Both are good spots to hone your skills for entering your slip.

A reason to leave the line on a fender is to scare you from using high throttle in gear when coming along side. If you were retrieving a person out of the water, you wouldn't want to hit reverse, throttle up, and pull their legs into the prop. You also don't want to pull the fender line into the prop. So using a fender gets you MOB practice at the same time as docking skills.

When my dad got his first trawler (CHB 42), we went out on Lake Union and I threw out a plastic milk jug. The first couple of attempts scared him, as it should have. He couldn't stop within 40 feet. When he got close it was because he was going to run over it. Again, we tend to think of the car analogy. We want to park in the garage but then smash through the living room over and over. Frightening and humbling. Several hours going in circles around a fender can really help.

 

[Cold Duck]

Interesting that your MS350 walks to stbd. Maybe she has a counter clockwise prop? Are you turning the rudder hard to port?

When the wind is blowing, we open the isinglass up on the Flybridge to cut down on being pushed when docking. We need to start practicing. Thanks for the advice.

That's the point, almost doesn't matter where the rudder is, ours will walk stbd, yours port. In calm winds I can turn rudder slightly to port and use "bursts" of power that will let boat back straight or slightly to port ( I am bow in to my slip. Usually returning in afternoon the wind is high and I don't even think about sterning in). But it's almost not worth the effort. Better to walk boat out of slip and push stern to port then as we clear the slip, bowthrust the bow to stbd so we can leave with the bow headed to stbd. Of course, any wind especially from port and this may or may not work. Many times I have just had to come out heading to port and do a 180 outside the slip to head in the only direction to leave the bay.

 

[porman]

engine rotation

So some transmissions rotate the shaft and prop in the direction as the engine crankshaft and some transmissions reverse that direction of rotation? That would explain some of the confusion about which is which.

Back when most small boats had gasoline engines it was common in twins to have one engine be reverse rotation. That way one prop would turn clockwise and the other prop would turn counter clockwise. I had a friend who did not think about this when he replaced the starter motor on his reverse rotation engine with a standard rotation starter motor. Things did not turn out well.

 

[psneeld]

Anyone reading a lot of this advice has to realize that while there is "some" similarity in boats and how they handle.... size/pitch of props, size of rudder, keel shape and size, Beam/length ratio...and more all affect how boats handle.

Comparing dissimilar boats and trying to use exacting procedures advised may not get one the same result.

Sometimes it takes a very experienced captain many tries at docking a new boat in certain conditions because "old tricks" don't always transfer.

Practicing with a similar to yours or actually your boat is key and anything that helps like thrusters does a lot t simplify getting a boat to do what you want.

 

[koliver]

The hardest part of boat control to get used to is the speed of the water across the rudder.
In fwd gear you know when you lose steerage as you slow to something around 3 knots. In some boats, loss of steerage occurs at a higher speed than that when the engine(s) are in neutral.
Now think about reverse. How often are you reversing at a speed greater than 3 knots? Almost never for most of us. Now think of going fwd at less than 3 knots with the engines in neutral and trying to turn into your slip. For this manouever, unless some fwd power (prop wash against the rudder) is used, the boat will be just as unresponsive as if you were in reverse, just because you don't have prop wash pushing against your rudder.
To master tight manouevers, you always need to keep your prop walk, wash against the rudder surface and boat speed in mind.

 

[LindaFlorida]

Great advice… thank you! Looking forward to practicing.

 

[Bacchus]

I am not familiar with the hull shape aft of your 34. Do you happen to have a photo of the stern out of the water, or do you perhaps know if there is a prop tunnel?

Rich
Excellent point and I don't think you got an answer or anyone mentioned or considered this.
YES the late model year single eng MS 34 Ts & HTs have a substantial prop tunnel that negates almost all of the prop walk. They will turn easier one direction (CW) than the opposite, using back & fill but they back fairly straight in calm conditions.

 

[ranger58sb]

Great advice… thank you! Looking forward to practicing.

I often suggest our new "students" dock five times, every time they return to port.

Dock, review good/bad, leave, do it all again...

-Chris

 

[ABfish]

I often suggest our new "students" dock five times, every time they return to port.

Dock, review good/bad, leave, do it all again...

-Chris

That's a great idea.

 

[Shrew]

My boat has a single. It backs to Stbd. The lower helm is to Stbd. The lower helm door is to Stbd. The Stbd midship cleat is right as the lower helm door. The entirety of the galley cabinets is to Port.

If my boat backed to Port, I would reverse the transmission and get a prop that turned in the opposite direction.

 

[alormaria]

My boat has a single. It backs to Stbd. The lower helm is to Stbd. The lower helm door is to Stbd. The Stbd midship cleat is right as the lower helm door. The entirety of the galley cabinets is to Port.

If my boat backed to Port, I would reverse the transmission and get a prop that turned in the opposite direction.

And ain't it a bitch when the lockmaster asks you to tie up to the port side lock wall.

 

[SteveK]

And ain't it a bitch when the lockmaster asks you to tie up to the port side lock wall.

They appear to have a sense of humor.

 

[LindaFlorida]

Rich
Excellent point and I don't think you got an answer or anyone mentioned or considered this.
YES the late model year single eng MS 34 Ts & HTs have a substantial prop tunnel that negates almost all of the prop walk. They will turn easier one direction (CW) than the opposite, using back & fill but they back fairly straight in calm conditions.

Yes, we own a late model 34T with a substantial prop tunnel. What does (CW) mean? Thank you

 

[SteveK]

CW clockwise rotation
CCW counter clockwise

 

[Serene]

My boat has a single. It backs to Stbd. The lower helm is to Stbd. The lower helm door is to Stbd. The Stbd midship cleat is right as the lower helm door.

[SNIP]

Same as my boat. I always dock bow in, starboard side to.

Not sure if it has been mentioned, but the amount of prop walk is also determined by the shaft angle. The greater the angle the more prop walk.

 

[genedanko]

I have a 1979 Mk I (the 34 flybridge) with a right hand screw. Theoretically, it backs to port. But in the real world it has a mind of its own because the rudder is about 200 square inches located almost a foot behind the propeller.

Forty years of backing sailboats does not come close to the excitement of putting my trawler in reverse.

Last year I installed a bow thruster and life is much better.

 

[Estranger]

When reversing the rudder is out of the equation for a single screw. You can turn it to compensate for the prop walk or slide when you put it in forward just enough to straighten out your stern and then return to alternating between R and N. Let the momentum of the boat do the work for you. Do not try to force it or you will lose!

Go over to the quest dock and do a couple of T & G before walking her in the slip.

Above all have fun and you will master it.

 

[Ed C]

Just buy Boat Handling Under Power, by John Mellor. It’s does the best job of teaching handle prop walk.

 

[RustyPBucket]

I have right hand drive on our boat and one lesson I learned very early was that throttle is my friend. Was coming into a berth on the starboard side and the current was ripping out at about 4 knots in the direction I was traveling. Was doing everything right, had the proper angle, turned the helmn to hard port and the bow started to move to around and when I thought it was the right time put it into reverse and that was when the engine stalled. The next few seconds was pure instinct I’m sure. I bumped the the throttle, hit the key and when it started it was already in reverse and I hammered it hard. The old girl stopped almost instantly and she walked over to dock no problem. When things had settled down and my feet were on the dock an old timer that was there and had grabbed a line asked me how much I experience I had, I answered honestly and said very little. His next question was what did you learn? I thought about for a bit and told him, next time the engine will off idle a bit when I change the direction and that it appeared that lots of throttle was my friend. He patted me on the shoulder and told not to forget those points and I would be ok.
After that I watched closely and what I saw was skippers got into trouble doing the idle thing and long fingering it as my ole man used to say and the ones that got the best results were the ones that made lots of noise and were active on the wheel.
I can back down our fairway which is six hundred feet long in reverse no problem, make corrections as I go. Practice, practice and more practice and threads like these are full of good information.

 

[PhilPB]

I have a 1979 Mk I (the 34 flybridge) with a right hand screw. Theoretically, it backs to port. But in the real world it has a mind of its own because the rudder is about 200 square inches located almost a foot behind the propeller.

Forty years of backing sailboats does not come close to the excitement of putting my trawler in reverse.

Last year I installed a bow thruster and life is much better.

Indeed it is! Bow thruster was the most valued expense for me. Today, the wind was about 15mph with 20mph gusts but backing into my slip was a breeze

 

[Capt Ray]

I'm going to take a different approach for MY answer to this one... no flaming please ... for my "alternative" advice!

I have a 2000 Mainship 390 single screw with bow thruster. RH prop... so it will pull a bit to port when in reverse especially I goose it a little when docking port side to, and I want to bring the stern into the dock or lock.

However, prop walk is not the "magic" that I would recommend you practice first!

The original owner replaced the push button bow thruster controls with joysticks. The marina we were at on Great South Bay Long Island NY had a slip that we preferred to back into (easier for my wife to get on+off), and the fuel dock was also most often easiest to back into to take on fuel. After a couple weeks owning this boat, something in my brain "CLICKED."

With the rudder amidships, and my arse sitting on the wheel at the upper helm looking aft, I put my left hand on the F-N-R Shifter, and my right hand on the bow thruster joystick.

The concept is to drive the boat backwards as if I were pushing a grocery shopping cart backwards (from its bow). I can move my ass-end (actually the boat's BOW) left and right, and I simple line up the stern to go backwards into the slip (or wherever I need it to go), using these two controls (engine at idle.)
"Our favorite shifter position is NEUTRAL." So gentle "bumps" aft or forward are the rule as needed.

There are several videos in these blog posts which illustrate this technique even in non-ideal current and windy conditions.

https://shellerina.com/2023/07/21/backing-into-grand-manor-marina-slip-with-wind/

https://shellerina.com/2021/07/29/tight-dock-landing-at-mackinac-island/

https://shellerina.com/2022/09/17/deliveries/
((The video is at the very end of this blog post shows us backing in against 2K of current, at Hoffmans / Manasquan River NJ.))

https://shellerina.com/2023/09/04/waterside-norfolk-va/

https://shellerina.com/2022/04/11/time-lapse-passage-to-icw-mm-zero/
Again, the SECOND video shows us backing into a slip here at Tidewater in Portsmouth/Norfolk Harbor VA with a crosswind that we use to our advantage!

Whenever possible, figure out how to use current and wind to your advantage! In the Manasquan River example, the current actually helped me, as I could move the boat SIDEWAYS in the current coming at my stern.
In the Tidewater example, I simply used the wind to push me up against the finger I wanted to tie up to. In these ways, with planning and compensation, current and wind can be your friend! Rather than something that messes you up.


Summarizing... Once the 'pushing a shopping cart backwards' concept clicked in my brain, it all became VERY easy for me to put this boat in just about anywhere in all but the worst conditions. ((No stern thruster!))

My wife has MS and uses a cane, so I usually ask the dockmasters for a slip that is "close to civilization"... which obviously means more maneuvering into position down fairways. Lucky for me, we have this knocked! I hope this concept helps some out there... Good luck.

 

[ranger58sb]

I have a 1979 Mk I (the 34 flybridge) with a right hand screw. Theoretically, it backs to port. But in the real world it has a mind of its own because the rudder is about 200 square inches located almost a foot behind the propeller.

Forty years of backing sailboats does not come close to the excitement of putting my trawler in reverse.

Last year I installed a bow thruster and life is much better.

We had an '87 Mk III, right hand prop, the stern walked to port nicely in reverse. No issues.

Never (seldom) used the rudder while docking.

-Chris