Up to now in this Online Book, I have covered setting up to come alongside, and using a magic springline that makes the actual docking easy, but what about getting the boat close enough to the dock to get a crew member and a line ashore without hitting anything?
That’s what I’m going to tackle in this and the next few chapters, but first let me tell you a story.
We were in a commercial harbour in Newfoundland and, as so often happens when cruising “The Rock”, the harbourmaster had found us a great berth, in this case alongside a massive floating dock in the most sheltered corner of the harbour.
The next day another sailboat came in and tied to a high and rough concrete dock in a much more exposed area.
I wondered over to say “hi” and pointed out that there was a much better berth just behind us, and further in, on the floating dock. I also offered to catch their lines when they moved. The skipper of the other sailboat looked at me like I was an idiot and said,
Thanks, but we have a full keel.
It took me a moment of confused thought (do hope I didn’t have my mouth open) before I realized that what he was really saying is that he could not safely manoeuvre his boat into that snug berth.
The interesting thing is that this clearly experienced skipper (I could tell by looking at the boat) assumed that any damned fool would understand that a full keel meant that getting in and out of this berth was impossible.
The point of the story being that this, and many other boat handling myths, have become common wisdom.
And that’s sad, because if we learn to reliably get our boats in and out of tight spots we will have a far more relaxed cruising life, since the snuggest and most sheltered berths are nearly always the most challenging to get in and out of.
So let’s bust those defeatist myths.
To do that it’s vital to clearly understand how our boats respond to various power and steering settings. Yeah, I know, you’re thinking “here comes the boring theory, just tell me how to do it”.
Sorry, no can do. Most all of the coming alongside approaches that I see that don’t end well (including some of my own), are a result of not applying the fundamentals properly, so we need to cover a bit of theory if we are all going to become fellow members of the docking perverts’ club¹.
The good news is that there’s really only one base skill we need to learn to make getting alongside easy in most any circumstances:
Turning the boat with little or no forward motion.
One more thing, throughout these chapters I will be focusing on single-screw boats without bow thrusters, since if we solve boat handling for that configuration, those with twin engines and/or bow thrusters will be able to take this information and add in the additional benefits that said gear provides.
OK, enough blather, on to the meat of it.
I enjoyed the way the chapter was laid out. Excellent work as always. The video was great, especially with the personal touch of Phyllis orchestrating the maneuver. Thanks again for the valuable information.
Hi Russell,
Thanks for the kind words. Means a lot since this chapter was one of the most difficult we have ever tackled. Coming alongside is such a huge subject so figuring out how to break it down into easily digestible pieces is a real challenge.
No, really, excellently done, John and Phyllis. The writing was clear enough, but the diagrams in different wind profiles and the lovely shots of MC in action really sealed the lesson. Since I started working with the four-bladed RH Variprop in docking situations, I sometimes get questions like “why do you hit the throttle in reverse so hard when docking?” It’s exactly to kick the stern in so my altitude-challenged wife can get to the dock with a line! And as you point out elsewhere, you can motor dead slow forward with the right aft spring on and stay pinned to the dock without fuss until all lines are on. Great tutorial.
Hi Marc,
Thanks for the kind words.
Hi John
Just interested in your thoughts on retrieving an anchor and chain after a winch failure.
Haven’t had the pleasure yet but it is a situation that I am keen to hear some ideas on as Maree and I enjoy short handed sailing passages.
Currently in some off the track locations in Indonesia.
Hi Rob,
Please see our comment guidelines paragraph #1. This is particularly important now as the plugin we used to use to move comments has a bug and therefore I would have to move your comment manually.
This would be an appropriate post: https://www.morganscloud.com/2011/08/07/boat-windlass-requirements/
This chapter is fantastic, well done. It has remedied my boneheaded practice of trying to whip the helm from port to starboard when trying to work the prop walk.
To answer your question at the end of the article: In my view, the highlighting enhances understanding and reminds me of advice I received a long time ago when preparing speeches – tell ’em, tell ’em, and tell ’em again.
Hi Bryce,
Glad it worked for you although I think you are being too hard on yourself with the word “boneheaded”. Not moving the helm is really counterintuitive and it was quite a few years before I figured it out from watching commercial guys like Stein.
Hi John.
As I currently work as Skipper on tourist boats on the canals of Amsterdam, I get to practice extremely close quarters manoeuvres non stop. Much of the time, the boat length is more than the canal width. Quite often just barely more than the width. 90 degree turns come every ten minutes on average and the amount of other boats in any direction is often what would be called rush hour if it was on land. On the professional boats we use the VHF radio to announce our arrival before each tight spot.
I can, of course, support every word you say here. Without these techniques, one simply cannot go into the canals. With them, it’s actually quite easy to handle even big boats in there.
I will only add a level to the issue about throttle. On the canals, we use an on/off mode while turning. That means absolutely full throttle both in forward and reverse. The transition should be as quick as possible. The forward thrusts will be a bit shorter because the prop is less powerful in reverse. (On high powered speed boats, this is too much power, but on most any other boat…)
The reason for using so much power is that this technique is working with the inertia of the boat. The more acceleration force on a not much moving boat, the more it will rotate. So the slower the speed forwards, or the more power added, the sharper the turn gets.
This can be illustrated by in open water stopping the boat completely, turning the rudder fully over and giving full throttle forwards. The turning is sharp at first and then gets gradually less sharp as the boat picks up speed.
The classic newbie mistake in the canals is to ease the throttle in the middle of a sharp turn because one is afraid of hitting the side of the canal one is entering. That widens the turn much and normally results in bumping hard into the canal wall. Normally hurting the pride more than the boat. 🙂
On the new layout with boxes, I like it a lot. Visually separating the text pieces and making it easy to look back at some key issues is great. Makes it more readable. I think the text boxes should be quite short though. No explanation, just minimalistic key points. The biggest box might defy its purpose and seem like just normal text with another colour.
Hi Stein,
Thanks for a great explanation of the reasons for using plenty of power. As you say, not being afraid of the throttle is one of the hardest things to learn.
Also thanks for your thoughts on the alert boxes, makes sense.
Hey John,
Your hard work paid off. This is a concise and well thought out post. The layout and new highlighted sections are smart stuff and a perfect summary for quick re-reads. Thanks for the education and encouragement to get passed the myths that hold us back from enjoying a cozy berth.
Karl
s/v Celestial
Hi Karl,
Thanks for the kind words.
After an eventful parking in a tight spot last year which ended in some new gelcoat care of our insurance company I have absolutely enjoyed this online book (and read through the entire thing about once a month). We were actually out last weekend practicing this very maneuver (in hopes of avoiding a repeat of our event in the future) your video really helps with how this should work. I now understand a bit more about what we were doing wrong. (although we were very close).
I personally believe parking is the biggest stress in boating and your notes have really helped me understand and feel better about what we are doing.
We are currently moored in sweden were there is a lot of bow to cliff morning utilizing a kedge anchor in the stern. While its not docking I would very much love to see and read any tips you might have in doing this. (both mooring and unmooring)
s/v polarseal
Hi Ryan,
Thanks for the kind words. I agree with you, judging from what I have seen over the years, docking is the most stressful part of boating, although anchoring comes close.
As to the challenges on mooring bow in as you describe, let me think about it, although I have to admit that I have not done that much of it myself.
Perhaps I should see if I can get our Norwegian partner in The Norwegian Cruising Guide, Hans Jakob to write a piece, he and his wife Elie are brilliant at it.
While wating for the comments from the Norwegian AAC correspondents, I thought I might share my view on the Scandinavia moring challenge. Here goes:
There is an alternative to using the Scandinavian mooring style in Scandinvia – and that is binning it as useless.
As a Scandinvian, I have at least stopped using it. Why? Several reasons; the real anchor with chain is normally on the bow. The anchor aft is often smaller and with a vombination of chain and rope of worse, just rope, i.e. not really intended for keeping the boat put. Typically during the night the wind shifts. Then either your neibours boat is dragging onto yours, or visa versa. Result is the same, up in the middle of the night. Not my kind of fun.
Secondly, even if anchored alone bow to the rock, there is a fair chance I will be woken up anyway by the bow trying to have night snack consiting of granite.
Next, many of the places where a Scand. mooring is used are popular anchorages, leading to a busy camping site of floating tens. Not my kind of fun either.
So what do I do? I drop the main anchor in a nice spot and swing with the wind – and sleep well. If I want to go ashore, there is always the dingy. Even better, when possible, moor longside a steep rock face with fenders floating in the water to maintain distance between the rock and the hull. A couple of rock bolts and a hammer is handy to secure some ropes ashore.
Or maybe I just do not have the patience to perfect it?
Greetings.
Hi Petter and all,
Visiting Sweden and Finland definitely has the challenges that send you to free anchoring, but there are many benefits (especially for boats from other countries) to doing as the locals do. Firstly, many of the most appealing spots have limited or no free anchoring possibilities. Second, especially in Finland, local customs nudge you to not anchor in view of houses/pontoons which makes finding anchorages far more difficult. Lastly, there are electric cables going across many anchorages. These are well marked on shore and on the charts, but ruin (or make more difficult) many an otherwise idyllic spot. For this North American sailor, in remote areas, I had to push myself in the beginning to actively look for cables, water pipes and overhead wires. They are all well marked, but were not much of a concern in my boating life till I got to this area.
Doing as everyone else also allowed us social contacts that otherwise might not have occurred. It took a while to realize that my priorities are different from when I cruised in my home waters. There I looked for secluded gunkholes. Cruising more widely, I gravitate to the towns, people, museums and local culture. It might be argued (certainly an exaggeration) that secluded gunkholes are the same everywhere. Being tied to shore/pontoons also allowed easier access to the saunas which are most everywhere.
Local mooring customs are made far easier by a couple of devices in general use. I got a hook made that went on the end of a boat hook and was tied off on a mooring line that allowed an easier, less acrobatic method for picking up rings on stern buoys. The other device is a long pole with an ingenious method of putting a mooring line through a ring and bringing it back to the boat.
Beefing up your stern anchor and rode makes a big difference. I also, some distance from the shoreline (rock wall, sloping rocks or wharf/pontoon) would (holding my breath) set the anchor with substantial power in forward. Only after that would I inch forward to secure in a way that allowed us access to shore. (If crowded, secure to shore first and then ease the bow line(s) to set the stern anchor: this allows the boat to be kept in better control and not get frisky with the neighbors.
My best, Dick Stevenson, s/v Alchemy
Thanks for setting this straight, Dick, and for adding the social aspect to this. Much better approach than just throwing in the towel.
Greetings from a dead calm Irish sea.
Hi Dick,
Thanks for the tips on that. As you say, although I have big reservations about mooring fore and aft, we must also learn from local custom.
Hi Petter,
I think that is very good advice, and very much the way Phyllis and I think. Just to expand on a point you make, the loads on the gear for a boat anchored fore and aft with the wind on the beam are far higher than most sailors realize. More here: https://www.morganscloud.com/2012/12/14/one-anchor-or-two/
Hi Petter,
Just another perspective. From a bit of first hand knowledge of the Irish Sea, you are likely to not have long to wait for wind.
Hi John, Your reservations are entirely warranted. I am usually the first to bail when things get boisterous. The forces on the beam to a vessel moored fore and aft seem to go up exponentially, as you have observed in the past, but also all the upwind boats are too likely to have their anchors drag (or slip a little) so that the whole line up ends up on your stern anchor. Extrication was not pretty and we felt lucky to have no damage.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Now there’s a nasty scenario I hadn’t thought of. Thanks for sharing it. Knowing of that danger could save someone a lot of grief.
You mean you don’t turn counterclockwise in the northern hemisphere and clockwise in the southern!?
Charles Starke
s/v Dawnpiper
🙂
Perhaps that’s a new low (in humor!)
Great detail of the process John – good to read it and have my own hard-won (paint and scrapes!) lessons validated. I was very interested in this as a kid, working a small, single-screw RC model tug in a local pond. I built a scale barge from plywood and goop and loaded it with rocks; and spent countless hours in all kinds of wind conditions learning with that model – taught me a lot. And burned through a lot of batteries! I then used the same tug to pull me around in a small canoe – sitting there in my “supertanker” as the little underpowered tug could barely handle the windage and mass. really good and fun lessons. of course it gets more real when the masses go up exponentially…
One aspect of this that I’ve learned from many yacht and commercial vessel deliveries is the need to be intimately familiar with the controls of the particular vessel. Our current 47′ steel ketch came with the annoying little side handles on the Edson pedestal. I hate them. there is simply too much opportunity to confuse which is which (throttle vs shift) and accidentally shift in our out of gear when the engine revs are too high. This could mean instant gearbox destruction. Hasn’t happened to me yet, but it’s only a matter of time- which is why I have a shiny new single-lever control in my shop and I’m working out how to fit it.
I’ve never had an issue on powerboats with twin handles – somehow it’s less probably, but I still much prefer single handle controls even there.
best-
bg
Hi Ben,
What a great kid-project. I just built a rig for a punt out of one of my dad’s shirts and a broom stick. No wonder you grew up to be an engineer!
And I totally agree with you about two lever controls particularly on sailboats (number 8).
Thanks for the write-up. I’m really looking forward to the future chapter on coming alongside.
I have a question but first I’ll relate a story that illustrates the importance of some of the factors you mention. I was trying to take my then-new-to-me Pearson 365 ketch (longish fin keel and skeg-hung rudder) out for a day of sailing in about 15 kt. My berth at the time was downwind and I was bow-in, with the wind on the port quarter. The marina exit was to port. I backed the boat out of the slip, and once sufficiently clear I put the helm over to starboard to try to turn the boat to port. Essentially what I would do backing out of a parking space in a car. Of course nothing happened… at least, nothing that I wanted to happen. We were going too slow to have any steerage. Instead, prop walk from our LH prop cooperated with the port wind pushing on the bow to move the boat directly to starboard until it was pinned against another wharf. And as always there was a large audience to witness my shame, who luckily took pity on me and helped me manhandle my bow in the wind so I could return to my slip with my tail between my legs.
Since then I’ve learned to work with these factors instead of against them, and I’m much happier for it. A lot of my knowledge was gained though other articles on this site, so again, thank you!
Anyway, I did have a question. My docking opportunities are almost exclusively slip-based (two-finger slips are common in California whereas single-finger slips were the norm in the PNW where I used to sail). I find that if I’ve successfully lined up the bow into the slip, the rest is easy – if the boat isn’t straight, I can use the techniques you describe above to move the stern into position. But if I haven’t lined up the bow, I sort of panic. I can turn the boat to point correctly at the slip, but now it’s coming in at a bad angle, because as you’ve pointed out what I’m mostly doing is moving the stern over. What would you advise here? And more importantly, what would you advise to avoid this situation? The only factor I seem to have control over is the point in time at which I make the turn toward the slip. Too early or too late and I miss. Boats not being cars, I find it very hard to visualize what the turn from a given point in space will look like, and I think that’s what’s holding me back.
Hi Adam,
Great comment that highlights a couple of important points, thank you.
First off, I think the biggest problem (and most understandable one too) in docking is that we all start by trying to apply what we learnt driving cars. When I finally realized (several years in) that boats are completely different and there is almost no crossover of skills, things got a lot better for me.
Second, the approach is all about putting the bow in the right place since once we slow down there is no way to move it. I will be writing a lot more about this in the coming chapters, but a key tip is: if the bow is in the wrong place, abort the landing, back out, and start again. There is no shame in this.
I will, in a tricky situation, frequently do a trial approach, to gauge the wind and/or current knowing full well that I’m not going to carry through.
And I have aborted as many as five approaches until I get one where the bow is just right. As to knowing what “just right” is, I will be covering that too.
A very good point. With a 16 tonne steel boat, I worry about other people, not us, and, if due to wind, misjudgement or I haven’t bled off enough speed, I do not hesitate to “abort” and go around a second time. In new places, I will also check out my surroundings and possible hazards first. Communication with the crew, however, is key, as this decision can be a surprise, otherwise. The stern of the “gin palace” ahead of us is a factor, but worry about looking like a tyro should not be. You take the time you need to dock safely.
my experience has been to keep all these techniques in mind while docking, but to first just do what always seems to be just natural…with my so-far-enjoyable saildrive (five years now) i discovered early on that prop walk is negligible so maybe this makes the difference allowing me to seemingly wing it although i find i do always need the short half throttle bursts esp in reverse…also i learned early on never to rush any of this, and i don’t hesitate to abort and restart if trouble starts to brew…i find tthe new highlighting to be most helpful…lastly for now, i see n b c will televise live this sat starting at 1 p.m. the americas cup racing fm bermuda’s great sound…i plan to be glued to the tube for this except i still must fight off the feelings that this is not real sailing, but i understand the event needs the foiling for the speed that draws spectators at the venue and on t v…cheers. r e s (s/v lakota)
Hi Richard,
A very good point: never hesitate to abort and go around again.
And yes, I too am following the AC, although I have to say I miss the wind related tactics that we see in match racing of boats that lose less speed in a tack in relation to straight line speed.
Hi John,
Great article. Looking forward to the rest. One hopeful request: please cover techniques and tricks for exiting the spot when its time to leave. I’ve moderately well mastered the techniques you describe, through trial and error and a bit of lost paint, and generally feel confident about bringing a boat in to park it in tight spots. It’s the leaving that is still challenging – especially in circumstances with a stiff breeze pushing us towards the dock. I’ve tried various spring line approaches, some combined with a fender held on the end against the dock, but they seem to require a lot of skill from the helmsperson and both skill and strength for the person holding the fender. Lots can go wrong, and if the fender pops out there is immediate damage. And on larger boats with high freeboard, the crew’s arms aren’t long enough to hold the fender at dock level. Would be grateful for your experience on exiting in addition to docking.
David
David – I too hope John will address challenges of leaving the slip. In the meantime, I recommend Duncan Wells’s book about short-handed boat handling: http://geni.us/ZDOwnS
Hi David and JZ,
I will definitely cover getting off the wharf in a future chapter.
John – I’m loving this book, since close-quarters maneuvering under power is one of the most underrated skills in cruising. (Yet one of my favorites! ?)
I learned the technique you describe in this chapter at OCSC Sailing in San Francisco Bay. It was a big focus of my “bareboat cruising” course there, and I’m grateful for such a thorough introduction.
The instructors called it “back and fill,” a reference to turning square-rigged sailing ships. Have you heard that name for it?
Hi JZ,
Glad to hear that someone is teaching this properly. I have never called it “back and fill” but it’s a great name from the days of sail.
John,
You have put into words something i have been trying to explain for years!
Hi Sam,
Thanks for the kind words. That’s exactly how I felt about the problem: how the hell do I break this down and make it understandable? I must have rewritten this post 20 times trying to get that right.
Hi John,
I have read lots of articles on maneuvering sailboats under power over the decades, but none comes close to the series you are putting out. Your hard work and clear thinking are impressively apparent.
A couple of other possible maneuvers for those more faint of heart or still learning the techniques:
If I am nervous about a down-wind side-tie such as the one portrayed in the article, I tie up facing downwind and warp the boat around to face outwards. You may get some quizzical looks from the peanut gallery, but, with proper set up of lines and fenders, this is a largely bulletproof way to turn the boat around.
I am not sure I would do it today with better skills, but when going into a narrow down-wind channel and needing to turn 180 degrees, I would drop my anchor just so it touches the bottom (not laying it down, just touching). I would then do the backing and filling, but the bow would come around and face upwind far faster. The drag of the anchor and chain through the water made a difference even before the anchor kissed the bottom. Good coordination bow to helm helps and this is certainly not a maneuver for all situations, but there may be a few.
My best, Dick Stevenson, s/v Alchemy
Hi Dick,
Thanks for the kind words, much appreciated, particularly given your experience and the amount of reading that I know you do—makes the effort worth while.
And yes, a couple of great suggestions.
One caution for those considering using the anchor dragging trick: there tends to be a lot a debris, including mooring chains, around wharfs, so the risk of fouling something at the the very worst moment needs to be balanced against the very real benefits of keeping the bow under control.
John,
Welcome back from your holiday! Very good post and right on target. Prop walk is a friend in maneuvering! In my experience however, we have found that in reverse, if one wants to spin the boat, and to therefore enhance prop walk, we put the engine in slow reverse, and then the usual burst you describe for forward. This allows the prop to spin longer in reverse, slowly bringing the boat to a stop, and all the while dragging the stern to port. We found this to be more effective than a burst in reverse, which accelerates the boat more rapidly, causing you to have to switch from F-R more frequently. Conversely, if we want to backup straight, we give a burst of reverse to gain way backwards and flow backwards over rudder and minimizing the time spent in reverse, which causes the stern walk. Regards, Conor
Hi Conor,
Sure, that will work, although the turning circle will be larger with a slow reverse. Also I have always found that I get more prop walk with a burst of power in reverse. That said, if it works for you that’s really all that matters.
Conner
We use the same technique for the same reasons you do.
Hi John,
Well said, the ability to spin a boat in a limited space is a crucial technique. I get a kick out of watching everyone saw the wheel back and forth trying to do this when there is a much easier way. This is even worse than many people realize since if you turn the wheel early before the flow is going the other way, which most people seem to do, you get an angular acceleration in the wrong direction.
I have found your technique also applies to backing up many older designs that have no reverse rudder control in a straight line although the wheel ends up hard over the other way. Quick bursts of forward can counter the reverse propwalk and you never need to spin the wheel, only use the throttle to back and fill your way in a pretty straight line.
Unfortunately, I have been on a few more modern designs with saildrives where there was so much separation between the prop and the rudder that your technique doesn’t work that well. All of these boats steered well enough in reverse that it wasn’t a big deal but spinning in close quarters in a cross-breeze would have been a bad idea.
Eric
Eric – our previous boat (a Sabre 38) had an offset prop, so there was no prop wash at all! Handy for maintenance, but a pain for turning.
One small consolation is that the prop was offset to port, which helped turn the boat to starboard. Combined with prop walk that pulled the stern to port, we could do a halfway-decent clockwise “back and fill”.
Hi Eric,
Good to get confirmation of the base technique from an engineer, as always.
And yes, I imagine that a saildrive could change a lot, but I have never handled a boat with one, so don’t have anything to add on the matter.
By the way, do you (or Matt Marsh) have a explanation of the physics that cause prop-walk? I have head a variety of theories. For example that the water is denser at the bottom of the prop spin circle than the top, but that one seems suspect in that I don’t think that water compresses?
Hi John,
I don’t know enough about it to say what the cause of prop walk is. I have heard a few plausible reasons (and several not plausible ones) but I don’t know their relative contributions. Hopefully Matt knows.
Eric
Hi Eric,
My thoughts exactly. The ability to use prop wash for maneuvering is dependent upon there actually being prop wash. Don’t try it with an old IOR two tonner with a hydraulic drive and folding prop emerging from the keel!
Hi Richard,
There’s not much I want to try with an old IOR two tonner! What terrible boats that rule produced. (I did much of my early offshore racing on IOR boats.)
John, the book is coming along swimmingly! I enjoy the layout of the chapter, with the callouts – A question for y’all. How does a feathering prop effect the physics described in the chapter? Do these changes in the physics have any real world effects on the lesson? I’ve noticed on our new to us boat that there is appreciably less prop walk with the Featherstream, and it seems to be less dependable that the prop walk will be there than our old full keeler.
I’d also love to here more about how current effects many of these docking maneuvers, perhaps individually in each chapter or a chapter that describes the changes to the maneuvers one might employ with a strong current. We have a constant current of between 2-5 knots moving us off the wharf, which seems to add some extra challenge.
Hi Dartanyon,
Great name! I love it.
I have heard there is less prop walk with the Featherstream. I believe it is made by Darglow in the UK and, if so, then Chris is the prop man there and is extremely helpful and will clarify the question of whether there is less prop walk and why. I have also heard recently the same about Max props. I find I have good prop walk with my Max prop, but it too long since I have had a fixed blade prop to remember any difference.
I will say that, if there is less prop walk, then it is more than made up by feathering props having far more thrust in reverse.
And WOW, 2-5 knots of current. At least you report it is constant, but in general, I would rather deal with 20-30 knots of wind over significant current. In part because the underbody profile the water sees (bumps up against) changes the way the boat behaves rapidly and dramatically (straight on- no big deal: turn broadside and you are off to the races). I have found current in confined spaces can make things go pear shaped impressively— and there is always an audience.
All that said, the few times I have approached a dock up stream and felt that coming in for a side tie was unlikely to end happily, I nosed in, lassoed a cleat with a bow line and winched the stern in. Took time and was far from elegant, but was not likely to end in damage or humiliation.
Current is tough also because it changes in a marina as a result of marina structures, and boat under water configuration upstream so I find it often unpredictable/undependable. At least a couple of times, I have asked/insisted the marina have a work boat stand by or give a tow.
My best, Dick Stevenson, s/v Alchemy
Hi Dartanyon,
Like Dick, I have a MaxProp and still get plenty of prop walk, so I would have thought the same would apply to the Feathersteam. That said, my big problem in answering this question definitively is that I have not yet heard a really convincing theory from a qualified person on the base physics of prop walk. See my question to Eric. I need to research this more.
As to current. I’m thinking the best way to handle that is a separate chapter because current actually has a very different effect on a boat than wind does. The basics of this difference is that how wind effects a boat depends on the boat’s attitude to said wind, as I discuss in the post. However current’s effect does not change with the angle of the boat to the current, except in relation to wind, if any.
I noticed you’re making updates to this book again, but still haven’t seen a chapter about current. Is that in the works?
Hi Christos,
I have been thinking about it, but no specific schedule as yet. I will think some more with your encouragement.
Very good write up on doing the spin move as I call it. I’ve been doing this for years as part of my approach to backing into the slip. I initiate slightly differently and typically only have to shift gears sort-of twice, initiate turn, forward to neutral once rotation has started well, then neutral to reverse at a around 60 deg rotation to get the prop walk working, and feathering throttle only enough to keep movement toward alleyway sides to a minimum, then throttling up more to get effective rudder control in reverse. Granted, I have a deep fin keel that makes a sharper spin easier. A full keel, or much tighter alley, would probably need your near full stop method.
Hi Joe,
I will be covering backing in in a future chapter, but, as we both say, this is the base skill that makes everything, particularly backing in, possible.
Thanks for this clear and precise presentation on docking. We own a full keel 1983 Nauticat 36 and were struggling with docking this new to us boat. Followed your instructions and we were absolutely amazed at the difference. In the narrow space between the 2 docks we were able to turn 90 degrees on station and ease forward into the slip. We were even turning into a 10 kt crosswind. I am sure we will continue to face docking challenges but this success has boosted our confidence and reduced the stress level upon returning to our dock.
Robin
Hi Robin,
Thanks so much. Hearing that this Online Book has made a real difference is a huge boost to get on with the next chapters.
Re: prop walk. I made a prop and shaft from an index card, tape, and a pencil, and found it more enlightening than Google in this case. Make a RH prop and hold the shaft level with the blade length parallel to the water surface. Sight along the blade lengthwise. Now tilt the shaft downward until one of the blades appears to be perpendicular to the water surface. That one is clearly not pushing much water fore or aft, and it happens to be on the port side. The starboard blade, though, has increased its thrust in the fore and aft direction.
Hello John and fellow AAC,
Very well done. The key points highlighted is a good iniative.
Two comments :
1- Shifting quickly between half throttle backward and half throttle forward is not very good for tansmissions. I always try to leave a second or two for the shaft to slow down or stop. Most times just engaging gear or with little throttle is sufficient unless wind and or tide are strong despite the Gori feathering prop.
2- for boats with bow thrusters you can even creep sideways by combining bow thrust one way and prop wash heading the other way in short bursts so not to go forward.
In further posts you could give tips on the good use of thrusters ?
Denis
HR 46 Hibernia II with Yanmar 110hp , Aquadrive with Gori prop and 10hp bow thruster
Hi Foster,
Good point that a little hesitation when shifting is easier on the gear.
As to thrusters, I have never had one, and therefore I’m a bit handicapped in writing about them. Also, I think it a good idea to to build the skills to do without them in case of failure.
That said, I think those that have them can fairly easily mentally add their usage in to each manoeuvre as I discuss it. For example, in the exercise discussed in this post, bursts from a bow thruster would just speed up the whole operation.
Hi Denis,
When you suggest just putting your boat in gear or just a little throttle does the job, I wonder what difference it makes that you have 110 hp engine at your disposal. Most mid-40 foot boats operate with far less potential thrust, so ½ throttle for you could/would be way overkill depending on gearing and prop.
My best, Dick Stevenson, s/v Alchemy
Hi John.
I’m not an engineer, so I look forward to comments from the more qualified. Still I’ve wondered about why we have propeller walk. I’ve come to the opinion that it might work this way:
On boats, the propeller has limited space. Normally the top will be close to the hull, while the sides and bottom of it operate in open water.
The propeller will not make a straight current, but rather rotate the water significantly well outside of its own diameter, this rotating current will hit the hull and be slowed down there, while on the low side, the rotating current will go free.
This imbalance creates a side force that is consistent with the observed facts. Also it may explain why different boats and propeller types have very different prop walks. Proximity to the hull, amount of tip vortex from that specific prop blade profile, etc…
Hi Bob and Stein,
Thanks for the thoughts on the cause of prop walk. I like your theories a lot better than most of the others I have heard.
Hi John,
Great Article on a hugely important topic that causes more grief with new (husband and wife sailors) than anything else I can imagine.
As an engineer, I confirm Bob and Stein’s explanations for prop walk are correct.
Sail drive – hull reaction to the radial flow
Shaft drive – hull reaction to the radial flow plus different prop angle port and starboard. This explains why sail drives have less prop walk.
Cheers,
Pat
John
Great book that is very insightful and well presented with the diagrams helping greatly with the understand. And the excellent video is worth watching a 100 other docking maneuvers as we are able to put your video into context. After upgrading from a 22″ trailer sailer with a outboard which l was able to move in any direction due to being able to pivot the prop through 360 deg to an Ovni 455 which initially would only turn in a straight line, l have had a steep learning curve in boat handling. Luckily l have a bow thruster though l try and use it as little as possible. As the 455 has twin rudders and as such has no prop wash over the rudders it would be great to get any hints and trick on maneuvering with twin rudders. And if you lack the experience with twin rudders maybe others can chime in. From my experience so far all you say works for twin rudders though you get zero steerage forward so the turning maneuver just takes longer and with more slippage sideways.
Thanks for all the great articles and book
Chris, SV Effendi
Hi Chris,
Thanks for the insights on twin rudder boats. I’m afraid I don’t have a lot to add because I have never handled one. That said, the issue of no prop wash over the rudder is going to be a big drawback in manoeuvring no matter what one does, so I think my position would be to strongly advise that anyone who buys a twin rudder boat should make sure it has an adequately powerful bow thruster, or fit one.
Hi Chris,
I have no doubt that the arrangement on your trailer sailer would be hard to beat.
Re the Ovni, I also have an Ovni 445 that the previous owner fitted with a max prop.
I find it develops comparable prop wash to my previous Hanse 400e which had a single spade rudder.
I always approach slowly and make sure I give her plenty of throttle, at least half to three quarters. On my Ovni 445, the rudders are comparatively close together which ensures the prop flow will interact with at least one of the rudders.
I’d expect many of the twin wheel boats with widely spaced spade rudders that allow most of the flow from the prop to pass between them would struggle to develop significant prop wash.
I agree with your comments that the bow thruster also helps, especially if the keel is up. It makes sense to use all tools at your disposals.
Cheers,
Pat
Hi John,
Excellent post, and so eloquently explained.
Personally I consider myself fortunate for having been taught this technique early on by a very good friend and sailing mentor. I think it was the 2nd time we took my then new to me 35ft boat that he first showed me how to do this and got me to practice it under his very patient guidance. I am and will be forever grateful as the technique has served me well.
I am based in the Med, (Home port: Malta) where most of the mooring we do is stern to. Back and Fill works winders when maneuvering in tight spots.
My boat is kitted out with a Flexofold 3 blade folding propeller which when compared with my old fixed prop does not give away much when it comes to reversing. The only adjustment i’ve had to make is to use a little more RPM in the first few seconds when reversing to ensure that the blades open up properly.
Having read some comments above about using low rpm for a longer time in reverse, personally a strong burst at about 60% throttle works best for me as it gives an instant kick to port without putting appreciable any way on.
I think it would be useful and interesting compare experiences with other prop designs, especially for people for have made the switch from a fixed prop to a feathering / folding prop.
Best Regards & Thank you for all the hard work.
Patrick
I switched from a fixed two blade prop to a 3 blade Kiwi prop (feathering). I was expecting less prop walk but ultimately that was not the case. What I did get was much more immediate and powerful reaction to throttle inputs (especially in reverse). That was what made slow speed manoeuvring easier with the new prop.
I’m still learning though, John’s tip on berthing on the “wrong (starboard for me) side” of over steering to compensate for the walk in reverse is a good one to get the boat parallel and stopped that I hadn’t consciously thought of before. Still, I feel on balance you will always end up with the boat further from the dock than if you berth on the “right side”. I usually make sure docklines are plenty long enough if going in starboard side to and count on a bit of brute force heaving or springing or whatever to get in close. Luckily with a 3.5 tonne boat that isn’t usually too difficult.
Hi Robin,
Every boat is different, that said we don’t have any trouble getting our boat right alongside either side and I worry a little if brute force is required. So I can understand this better and make sure we are on the same page, do you have a right or left hand prop?
Right hand prop – boat walks to port in reverse
TBC – I’m talking here about a scenario of docking starboard side to against a long pontoon/quay between two boats already tied up with a space of about 1.5 boat lengths between them.
Hi Robin,
Actually, for a right hand propped boat I find a starboard side-to landing the easy side, even with boats each side, since if you are too far off you can alway move closer. See the post above under “easy side”.
Oops, sorry, in fact I discuss the easy side here: https://www.morganscloud.com/2017/06/23/coming-alongside-docking-the-approach/.
The post above discusses the easy and hard side in turning, as it relation to wind direction, not the final approach.
I just had this issue over the last weekend. I did a rare starboard side docking with my RH prop and was careful to just coast in as I knew I would swerve the stern off the dock with too strong a shot of reverse; this is exactly how I dock at my own club to port.
Leaving, however, was a lesson learned: the prop walk I use to slip our full keeler’s stern to port side with a quickness isn’t such a benefit when leaving from a starboard docking. As we were at the innermost slip next to the finger, I had to do some awkward spinning between rows of boats to get out. The solution(s) were: to have gone in stern first and docked to port; to have walked the boat back nearly to the bow of the boat in the next row, and then steered to port in forward; or to have walked the boat back and run a warp from the port stern bollard and motored against it to get the bow pointed out the “lane” between docks. Nothing bad actually happened, but I dislike putting on a show. I suppose the irony was that had there been any wind, the warping off idea would have occurred to me earlier, hence the term “deceptively calm”, I suppose.
Hi Patrick
I’ve observed the same response as you mention. Low power reverse gives much less prop walk than a powerful burst. Also the reverse burst is more effective when the boat is standing still or even moving forwards. When reverse motion has started, less side force is generated from another thrust.
These observations fit well into the explanation I mention above, about a rotating current from the prop being hindered by the hull. At the beginning of the thrust, unrelated to direction, the water flow will “wash off” the propeller ends just as much as the exit edge. THis creates a much larger diameter rotating flow than later in the sequence. As the effect of the propeller work gradually makes the water flow past the prop, and even starts to make the boat move, this flow will push the edges of the rotating flow inwards and reduce the diameter dramatically. The larger the diameter of the rotating flow, the more asymmetric the side forces will be, as much more water will be restricted by hitting the hull. This explains well why we observe the strongest prop walk when we use short but strong alternating burst forwards and reverse.
As mentioned, this is just my understanding of the topic, not at all authoritative, but I’ve studied Marchajs Bible (Aero- Hydrodynamics of sailing) since the seventies, so I think I’m getting at least one mechanism correctly. I wouldn’t be surprised, however, if there are more details and other effects to consider.
Hi Stein,
That makes sense and certainly fits in with my experience.
This is what I have learned as well, and because it is so effective (after a period of practice), I do not find prop walk a liability at all and wouldn’t enjoy docking a boat that did not exhibit it. I use it all the time!
John, I add my compliments to the others. Well done. After many years, I have learned to use most of your techniques, but I am embarrassed to say that I did not think about moving my spring line aft, as you suggest. It is in the center of the boat and then we have to have two lines ashore as you suggest. My question about a new, further aft attachment point: could I run the spring from my main sheet winch up to a block on the outboard Genoa track? Track, of course, is through bolted and strong, but the line would be turned almost 180 degrees around the block. Very different from running a sheet fore and aft. Is that kind of angle and stress acceptable?
Hi Terry,
I think that would certainly work for testing to find the balance point. However I’m not sure I would want to use that set up as a permeant solution since the 180 degree turn doubles the load on the toe rail block. The other point being that anyone in the bight of the line will be at risk if the block does let go. So if it were me, I would use the track to find the balance point and then install a good beefy fairlead.
John – Thanks for the great article. BUT……I have a RH prop on a 35′ boat long fin keel with excellent prop walk. Problem that I have is that I have to enter a tight shared slip by making a left turn. Doc finger is on my port. Other boat is on my starboard about 6 ‘ away. Once in, prop walk moves the stern into the dock.This is all made worse by the approach channel being narrow. Not much room for a missed approach. It’s pretty much a one shot deal. I seem to get it right about half the time. If not…then it gets exciting. Really exciting with wind blowing me into grouchy neighbor. Any ideas short of installing a $$$$thruster?
Thanks for reading this far…Conrad
Hi Conrad,
Good question. This is the classic problem where prop walk is working against you, and a very common one with that slip set up
I just drew this out and had a think.
First off Stein has some great suggestions, so see his comment below.
I have two other ideas, but this is such a great question I think I will write a post on it, complete with diagrams. May take me a few weeks since I need to get two other chapters published to lay the ground work for tackling your issue.
A possible way to handle your situation is to turn your boat around outside where there is space and then back down your approach channel until you have just passed your slip. If you do that, you will be turning to starboard to enter your slip. You’ll even have a little way on astern so you get a nice long dose of wash over your rudder as you drive forward for your turn in. This of course won’t work if your slip is right at the end of the approach channel, or perhaps in certain wind situations.