# Minimizing prop walk...



## MedSailor (Mar 30, 2008)

Full keel boats have their advantages.... and parking in tight places ain't one of them! My boat LOVES to prop walk (to starboard) in a big way. My usual procedure is to back up with the engine at low rpm and rudder hard to port, and begin swearing promptly when the stern goes to starboard as it always does. 

Is there an accepted way to minimize prop walk? Would I have less walk if I used quick bursts of throttle in reverse instead of a steady low/med rpm? Is there something else (besides a bow thruster) that I should be doing different?

Backing out of my slip is always the part of the voyage that I worry about, and dread the most. 

MedSailor


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## Stumble (Feb 2, 2012)

Quick burst of high revs will minimize prop walk until you get some steerage. You could also look at a feathering prop. Most of the feathering props will generate a fraction of the walk that a fixed prop will.


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## katsailor (Jan 6, 2013)

Less rudder, small bursts of throttle the get things going followed by waiting a moment in neutral to see wheich way she is going.
Your biggest enemy is going to full rudder, it seems to block part of the water flow to the wheel (storry old tug boater term) which causes negative pressure on one side of the boat.

from Wilkipedia

Propeller walk is the term for a propeller's tendency to rotate a boat as well as accelerating it forwards or backwards.

A right-handed propeller (which rotates clockwise [as viewed from the stern] when in forward gear) will tend to push the stern of the boat to starboard, thereby pushing the bow to port and turning the boat counter-clockwise unless the rotation is corrected for.. When in reverse gear, the effect will be much greater and opposite. A right-handed propeller run in reverse will push the aft of the boat to port.

Knowing of and understanding propeller walk is important when maneuvering in small spaces. It can be used to one's advantage while mooring off, or it can complicate a maneuver if the effect works against the pilot.

Propeller walk is a complicated effect which depends on ship geometry, direction of travel, propeller direction, vessel speed and depth of water. Three causes are identified for a vessel in deep water:-

Upward oblique flow at the propeller location. 
Vertical wake distribution at the propeller. 
Unbalanced lateral forces on the rudder (when set amidships) arising from the propeller slipstream impinging on the rudder blade. 
The first of these results from there being a measurable difference in speed of water flowing close to the hull and that at lower depths which has not been affected by the vessel's motion. At low speeds the last effect is most pronounced and when going astern has even more influence.

*In shallow water the upwards flow from under the vessel becomes much less strong and ultimately disappears. Model tests carried out show that, at a very small underkeel clearance, screw bias caused a ship to shear to starboard (rather than port) when moving ahead and that there is an intermediate depth where the shear from bias is neither one thing nor the other.*

Finally, when moving ahead with the propeller moving astern, flow into and around the propeller is very confused. Generally the overall result for a single screw ship when stopping is a shear to starboard, but this is not always guaranteed; sometimes it may go the other way, depending often on any yaw rate on the vessel when the propeller starts to turn astern.

sounds like a simple answer, you need a sli[p with an adjustable depth


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## celenoglu (Dec 13, 2008)

To decrease prop walk sail drives might be an option. The prop is close to the center of the boat and the prop walk tries to "walk" the whole boat to one side instead of pushing the boat from a long distance from the center.


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## davidpm (Oct 22, 2007)

I don't know it would work on a boat as heavy as yours but on some boats I have been able to counter act the prop walk by having a crew member shove the stern hard the opposite the stern will move once the prop walk starts.
That give you another second to two of stern-way before you have throttle back.

As an alternative a loose stretchy stern line looped over the cleat.
You start in reverse and when the stern line fetches up the stretch gives your boat a little way to counteract the prop walk then at the right moment you flip off the stern line.

In both cases the attempt it to over correct for the prop-walk with lateral force to give you a couple more seconds going mostly backwards.


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## knuterikt (Aug 7, 2006)

MedSailor said:


> Full keel boats have their advantages.... and parking in tight places ain't one of them! My boat LOVES to prop walk (to starboard) in a big way. My usual procedure is to back up with the engine at low rpm and rudder hard to port, and begin swearing promptly when the stern goes to starboard as it always does.
> 
> Is there an accepted way to minimize prop walk? Would I have less walk if I used quick bursts of throttle in reverse instead of a steady low/med rpm? Is there something else (besides a bow thruster) that I should be doing different?
> 
> ...


Every boat has it's quirks..

I have found that the best way to sort them out with a new boat (or testing new techniques) is to locate some empty mooring bouys to use for testing - not so hard if you miss

Some things to try.

More speed going aft (I know it feels frightening)
Turn to starboard before going aft countering the prop walk after engaging revers (assuming you get steering going aft with increased speed se 1)
When going aft keep the rudder to port, it wont be able to counteract the propwalk anyway), use bursts of forward to move the stern back in line
Test the other suggestions in this thread


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## jrd22 (Nov 14, 2000)

Med- our boat isn't full keel, but a long fin and large skeg hung rudder with a three blade fixed prop. It turns to port in reverse, a lot. I've found that putting the rudder just a bit to starboard and an initial blast of throttle until the boat is moving at least a knot or better and then shift to neutral is the best that can be done to try and back out reasonably straight. If I just let the engine idle in reverse I would hit the boat to port and the bow would scrape along the finger pier. If I have crew I will have them walk along trying to hold the starboard bow off until they have to climb aboard. I really wish I had a port tie slip because coming back in is not much better :-(( I think a Max Prop is in my future (when I save up 4K).


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## MedSailor (Mar 30, 2008)

Thanks for the suggestions so far. One thing I haven't tried is anything less than full port rudder when I really want to counteract the starboard walk in reverse. I could try a little less. 

I have used bursts of forward to good effect to get her back in line, but then again we often end up loosing our sternway. 

I don't have the coin for a feathering prop, though I covet them. This week we're going in the yard and I'm adding an inch of pitch back to the prop. It seems to me that this problem magnified significantly when I took 3 inches of prop out.

As for the slip, I need to experiment with lines to help. I do own the slip and can modify it, so I should take advantage of that. I've been meaning to try something I saw in "Good Old Boat" whereby you run a taught line or wire along your finger peer. You then have a short line with a sliced eye that slides along the wire as you back up. You can pull on the line while you're backing up and it will always be perpendicular to the slip.

MedSailor


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## billyruffn (Sep 21, 2004)

Don't know if it will work for your boat, but I've found that giving the engine a rev in reverse to get the boat moving and then putting it in neutral will usually allow me to steer while moving backwards. Once the engine is in neutral the prop walk stops and if you've got steerage the rudder should control things.


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## MedSailor (Mar 30, 2008)

billyruffn said:


> Don't know if it will work for your boat, but I've found that giving the engine a rev in reverse to get the boat moving and then putting it in neutral will usually allow me to steer while moving backwards. Once the engine is in neutral the prop walk stops and if you've got steerage the rudder should control things.


This is what I do as well (I probably wasn't clear about that) but what I think I need to experiment with next is how to get that initial steerageway. I've been using low/med rpm to get that initial steerageway but I think today I'll try more of a burst.

Agreed +1 about putting the engine in neutral once we're going backwards a little. Usually by then, I'm crooked in the slip and my bowsprit is about to snuggle up with a piling. 

MedSailor


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## jackdale (Dec 1, 2008)

I am with billy.

With a full keel you need more speed to get steerageway than a fin keel. 

Snug your stern in tight before powering up.

Have someone on the bow with a boat hook to fend off the piling.


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## Cruisingdad (Jul 21, 2006)

MedSailor said:


> Full keel boats have their advantages.... and parking in tight places ain't one of them! My boat LOVES to prop walk (to starboard) in a big way. My usual procedure is to back up with the engine at low rpm and rudder hard to port, and begin swearing promptly when the stern goes to starboard as it always does.
> 
> Is there an accepted way to minimize prop walk? Would I have less walk if I used quick bursts of throttle in reverse instead of a steady low/med rpm? Is there something else (besides a bow thruster) that I should be doing different?
> 
> ...


Hey MS,

I understand. Backing the tayana or even our boat can be a challenge. The trick if you want to back straight are bursts of speed. Never leave it in gear unless you want to walk that way. Prop walk is awesome! It got me in my slip today. Trick is learning how to use it. Also, when backing, shake that rudder until you have water flowing over it for steerage. Back and forth and you will get that rudder working.

Brian


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## outbound (Dec 3, 2012)

PS.- Had a Tayana. Sometimes if wind was right would use a bit of staysail to help line the boat up. Would back wind it as necessary then let it flop.


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## MedSailor (Mar 30, 2008)

Well today's test of using a burst of throttle in reverse seemed to really do the trick. That, and since the wind was really piping up, having someone on the dock yank the bowline at the last minute as a "poor man's bowthruster" got me out of the slip no problems. 

I've used a bit of mizzen myself as a poor man's stern thruster to counteract how much the bow gets blow off. With the mizzen sheet in the cockpit you can adjust how much you want it to affect your lateral stern movement. Nearly used it today, and would have if not for the friendly dockmate who could be the bowthruster. 

Backing up at low RPM before putting her in neutral is something I've been doing for years. Proof for me that just because I have some years experience doing something doesn't necessaraly mean I'm doing it right.


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## MastUndSchotbruch (Nov 26, 2010)

Cruisingdad said:


> Hey MS,
> 
> I understand. Backing the tayana or even our boat can be a challenge. The trick if you want to back straight are bursts of speed. Never leave it in gear unless you want to walk that way. Prop walk is awesome! It got me in my slip today. Trick is learning how to use it. Also, when backing, *shake that rudder* until you have water flowing over it for steerage. Back and forth and you will get that rudder working.
> 
> Brian


Shake the rudder?? Care to elaborate?


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## scratchee (Mar 2, 2012)

The best option is to buy a dock on the side of the prop walk.


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## MedSailor (Mar 30, 2008)

MastUndSchotbruch said:


> Shake the rudder?? Care to elaborate?


Is this what he means? 
Harlem Shake

MedSailor


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## RichH (Jul 10, 2000)

Med - 
Backing down a full keeler with its prop in a small aperture is unlike _*any*_ other configuration ... as you know. 
Such boats simply cant be 'steered' well using the rudder when there is little to no flow over the rudder and the keel. 
Prop walk, hefty prop walk, is your only means to turn and/or keep straight.

The key to this, is to 'master' the pivot turn (aka 'backing and filling'), using only prop-walk and with NO aid from the rudder (totally hands off the wheel), to be able to turn such a boat only by quick short bursts of rpm though a total 360° turn and within or close to a diameter of a circle equal to the boat's overall length, and to be able to do so in a clockwise and counterclockwise 360° within close to that boat length circle. There's lots of info about pivot turns and backing and filling on the internet ... good stuff on the USSailing website. 
Once you completely master the pivot turn with a full keeler with teeny prop aperture, backing down, or laying along side a long dock is quite easy ..... all becomes just a pivot turn of larger radius/diameter.

The one additional 'trick' for pivot turns with a full keel with the prop in a 'tight' aperture is the prop wash (not prop 'walk') impinging on a 'cocked' rudder (usually at 45° over) to help the 'walk' toward both turning/walking directions when going forward at 'zero' speed. The 'blast' of prop 'wash' against the cocked rudder so that boat turns in the opposite direction of normal expected 'prop walk'. Just set the rudder at 45° to the OPPOSITE side the normal direction of prop walk and use teeny blasts of 'forward' to help keep the boat aligned and 'straight' in the direction you want to do .... including correction of over-control errors when backing down. You get NO impingement of prop wash onto the rudder when going in 'reverse'. 
Obviously, you'll have to quickly and totally idle down between rapid transitions from reverse through neutral to forward, etc. to do this so you dont break the transmission or rip the blades off a feathering prop.

Once you 'master' the 360 pivot, in both directions and in within close to that one boatlength and NO USAGE of the rudder at all!!!! ... all the rest, parallel parking between honking big boats and pilings, etc. (ONLY to side where the boat will 'walk', never to the opposite side ... to *port*side ONLY with a right-handed prop), long straight line backing down, etc. becomes quite easy and routine. The easiest way with a full keeler is to NOT have so much speed on that causes water flow across the rudder ... and which only complicates the simplicity of using ONLY prop-walk to control the boat. .... use or add the rudder only 'after' you totally MASTER prop-walk and 360° pivot turns.

Most full keelers with teeney apertures have 'rub rails' ... USE THEM!!!! lay the rail against a piling and use the piling to help your 'pivot' or 'walk' - all depends where the piling is in relation to where the center of the pivot is on your boat. But, dont break the piling off when doing so, simply use low amplitude 'bursts' of rpm to pivot the boat laying up against and slowly sliding along a piling. (that piling used for pivoting should be on the portside of a boat with a right handed prop ... just like the dock/landing or entering a slip is always on that portside with a right handed prop)

Happy _backing 'n filling_ your drunken elephant, youre not driving a bus when youre _backing 'n filling_!


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## sony2000 (Jan 30, 2013)

With a full keel your prop is centered on the boat. Most people suggest a burst of power to start the boat moving, then to idle. 
You know the speed when your rudder becomes effective a little and when reaching that speed the rudder should be half way to full rudder. Too much and you are braking the acceleration.
Now a second burst of power to accelerate more, while the rudder is slightly effective. It can compensate for the walk at this higher speed.


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## MedSailor (Mar 30, 2008)

RichH,

I appreciate the advice on backing and filling and also on prop wash vs prop walk. I feel reasonably comfortable with turning the boat in tight spaces using these methods. 

For me, the big problem is just getting out of my slip without breaking off my bowsprit. 

My slip is 55ft long, is a single slip (so there are finger piers on both sides of me) and is only about 15ft wide. I have a 12'2" beam (plus fenders) but a lot less beam up near the bow. At the end of my slip, just beyond the finger piers, are two pilings that are just itching to damage my bowsprit.  So the end of my sprit must travel about 55-60ft in reverse, without going to port more than 7ft. Also, since I need to make a right hand turn out of my slip, in a perfect world my sprit would be deflected to starboard and would be narrowly missing THAT piling, not the port-side one.

I have gotten badly angled before in my slip due to my Starboard prop walk in reverse (LH prop) and had to put the rudder to Starboard and give her a goose of throttle to re-align and avoid snapping my sprit on the port side. Usually a big goose of power like that in forward gear all but kills my sternway and until I get going again I'm subject to the wind blowing by bow to port. 

Did I mention that in the summer the wind usually blows from my Starboard side, further adding to my bowsprit wanting to go to port?  Just about anything I can to do help my stern go to port, or keep my bow FROM going to port, is welcome.

Yesterday, pulling the boat so that it was snugged up against the starboard side of the slip, using a burst of reverse, using less than full left rudder deflection all together as a recipe worked really well (thanks SailNet ). In fact, I didn't even need the guy on the dock with a bow-line acting as a bowthruster but I might still see if I can rig a line for that task since it worked out so well. 

MedSailor

P.S. I'm wondering if I should just back in. Scary, but if I can learn that trick, it sure would make leaving a lot easier which is my current headache.


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## RichH (Jul 10, 2000)

Either go straight back until you cant go any further and THEN make your pivot turns OR if there is a piling at the end of your slip, lay the rubrail onto the end piling and either pivot turn around the piling using the piling as your pivot point ... or throw a rope around the piling, connected to your midship hawse hole .... and 'wear' the boat around it. 

Always better to back into a slip with full keeler. All the stuff that youre going to crush or hit is closer to the helmsman and you can better see whats happening because youre 'closer' to the impact zone. That said, that slip better be on your portside as you approach ... if you have a right-handed prop. 

;-)


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## MedSailor (Mar 30, 2008)

Actually I need (because of current and other things) to be starboard-to if stern in. Lucky for me, I have a LH prop.  I think I will try backing in. Sure will fix a lot of my problems....

Rope around a piling is another good idea, though the top of the piling is sometimes at waist height when standing at the dock, and is sometimes 16ft in the air. "What? How did that get up there? Damn Seagulls!"

MedSailor


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## RichH (Jul 10, 2000)

Loop the rope to the piling before you move the boat, grab it as you slowly pass by and snub-cleat both ends amidships.... drop one end into the water and pull the other end in, when you finish your turn. 

There's gotta be a big stout cleat near the end of the finger pier ... tie a permanent 'wearing' line to it, etc. 

;-)


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## sony2000 (Jan 30, 2013)

It's a loosing battle to try and turn a bow up into a crosswind at slow speed. Approach the slip from the other side and let the bow drop into the crosswind.


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## Cruisingdad (Jul 21, 2006)

MastUndSchotbruch said:


> Shake the rudder?? Care to elaborate?


"Shake the flutter from the rudder" (trademark and copyrighted by Cruisingdad... snicker).

I give the rudder a bit of a shake to get steerage (quickly turn the wheel or rudder back and forth a couple of times). This also helps when stuck in irons from a bad tack (not that it has ever happened to me). It helps to get a bit of water flowing right over the rudder, I guess. My theory on why this works is that the gravitational pull from the moon bounces off of Mars and reflects off the sun to your rudder when shaken. And until anyone else can give me another more plausible reason, I am sticking with my theory. Try it...

Brian


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## MedSailor (Mar 30, 2008)

Cruisingdad said:


> "Shake the flutter from the rudder" (trademark and copyrighted by Cruisingdad... snicker).
> 
> I give the rudder a bit of a shake to get steerage (quickly turn the wheel or rudder back and forth a couple of times). This also helps when stuck in irons from a bad tack (not that it has ever happened to me). It helps to get a bit of water flowing right over the rudder, I guess. *My theory on why this works is that the gravitational pull from the moon bounces off of Mars and reflects off the sun to your rudder when shaken*. And until anyone else can give me another more plausible reason, I am sticking with my theory. Try it...
> 
> Brian


I don't know if you're aware, but the US Coast Guard takes a dim view of drugs aboard....

MedSailor


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## jimgo (Sep 12, 2011)

MedSailor said:


> P.S. I'm wondering if I should just back in. Scary, but if I can learn that trick, it sure would make leaving a lot easier which is my current headache.


To me, docking is the most gut-wrenching part of boating. I can handle fouled lines, stuck rigging, etc. But there's something about the idea of crunching my boat into someone else's that really bothers me. For some reason, leaving the slip doesn't concern me as much as docking.

I used to back in with my old boat, which had an outboard. Backing in was much easier, because I could actually see what was happening as I docked, and with the outboard all the way at the back of the boat, it "drove" the aft end in the direction I wanted without a fuss.

That being said, there were significant disadvantages to backing in. Because of the shape of the boat, even though the midship area was close to the finger, the aft end still sat far away from the boat. The outboard hanging off the back made it difficult to angle the boat so I could actually climb aboard through the "gate" in the lifelines, and it was even harder for my wife (she's shorter than me by 6"+). And I found that the midships portion that was closest to the finger was WAY out at the end of the finger. In the end, my wife asked if we could go back to stern-in docking because she was more comfortable climbing aboard over the lifelines but amidships than the extra reach that was required when backed in. I'm not sure about how you have your Tayana laid out, but if you have anything hanging off the stern (solar panel, dinghy, etc.), you may actually find that backing in creates other problems that, while simplifying docking, may actually make it less fun to be/go aboard.

In our new slip, if we're stern-in, we'll also miss the parade of boats on the river.


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## Cruisingdad (Jul 21, 2006)

MedSailor said:


> I don't know if you're aware, but the US Coast Guard takes a dim view of drugs aboard....
> 
> MedSailor


Ha!!! This coming from someone who lives in Washington!?? (smile)

Brian


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## sony2000 (Jan 30, 2013)

Since I believe the wheel should be set only 1/2 way to port or starboard, you could start with say a full port wheel setting, gun the engine in reverse, and with a flick of your wrist set the wheel to 1/2 port. The movement of the rudder will help compensate the initial prop walk.

Secondly I would skip putting the transmission in neutral for a number of reasons. For example, it is overloading in tasks to perform, and the flow of water over the prop continues for a few seconds, whether or not it is neutral. After 7 seconds, a second bust of power would normally be used.


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## danstanford (Aug 3, 2010)

We are now in a very tight and short slip which is working ok when backing out with a west wind which blows from our port to our starboard because the propwalk pulls the stern up into the wind allowing the bow to blow down the fairway, This works great especially well since our bow is moving away from our slip mate on our port side (we have a starboard tie) with only about 3' between us. My concern is what happens when we get an east wind. Obviously we will want to move our stern up against the wind (to starboard) to back out the fairway but I am concerned that the prop walk will make that turn impossible till we get some way on by which time our bow will be blown down onto our neighbours to our port. 
To summarize, wind from starboard to port, prop walk to port, neighbour to port with a very tight slip. Help me with a plan....please.

Not only is the slip tight but I can just fit the length of our 33' boat between the end of our bock and the boats across the fairway. 

Current plan is to have my wife at the wheel with the rudder turned 10 degrees or so to starboard and me on the dock hanging on to the shrouds. Have her give a medium shot of power then neutral as I pull in and back on the shrouds holding us close to the dock and helping with the backward movement. As I run out of dock I climb on and navigate the boat out to the middle so I can then let the bow blow down and back out. 

Thanks, Dan


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## travlin-easy (Dec 24, 2010)

MedSailor said:


> Full keel boats have their advantages.... and parking in tight places ain't one of them! My boat LOVES to prop walk (to starboard) in a big way. My usual procedure is to back up with the engine at low rpm and rudder hard to port, and begin swearing promptly when the stern goes to starboard as it always does.
> 
> Is there an accepted way to minimize prop walk? Would I have less walk if I used quick bursts of throttle in reverse instead of a steady low/med rpm? Is there something else (besides a bow thruster) that I should be doing different?
> 
> ...


I have good news and bad news for you. First and foremost, you can back into your slip, but it ain't easy, and swearing seems to help more than anything else I, and many others, have tried.

I have about 10 feet of clearance from the boat on the opposite side of the fairway when I come in and out of the slip, and the back end of my boat is at the forward pilings and my bow is just 10 to 15 feet away from the boat across the fairway - too damned tight for comfort. And, this is not a place where you can gun the engine for more than a half second without getting into trouble.

In my case, and I should shoot a video of this, I bring my boat in as close to the forward pilings as possible, make a hard left turn, put the boat into reverse and allow it to slowly continue the turn until the stern is facing toward the slip entrance. Sometimes, of course, the wind and tide will not cooperate, which makes the process far more difficult.

Usually, I have to back down until I am just about to touch the piling, then quickly turn hard to port, goose the throttle for a half second, then quickly go into reverse, and turn the wheel hard right, which kicks the stern around until I eventually get lines up with the slip. This can take two or three tries on a good day. On a windy day, it could take up to a dozen.

The problem with full keel boats is YOU HAVE NO STEERAGE IN REVERSE - NONE! It just plain sucks the way these things were designed. The prop is way to close to the back end of the keep, which means you essentially have very little forward thrust from the prop. The thrust hits the back edge of the keel, which is usually flat and the majority of that thrust goes sideways, which makes it impossible to steer effectively. I know at least a dozen sailors that have full keels and have the exact same problem.

A bow thruster would be very beneficial in solving this problem, but they are quite expensive and not easy to install. Though I have seen one or two that are completely external and relatively easy to install. Keep in mind, though, that they eat batteries in a heartbeat. The power demand for them is insanely high.

The photo below is of my friend's Morgan 32 sloop with a 3/4 keel and you can readily see the problem of the prop thrusting against the flat surface of the keel.










My 33 Out Island has a full keel and the flat surface at the back of the keel is even larger and wider.










The only boat I owned that would park like a car was my 27 Catalina, which had a fin keel and the prop was hung on a skeg, well away from the keel or rudder. Of course, the prop and rudder snagged every crab pot marker and piece of seaweed they came in contact with.

Good luck,

Gary


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