Question:
I have a boat with twin rudders and a single propeller on centre line. Will your docking techniques in this Online Book work for me and, if not, what should I do?
Q&A, Coming Alongside (Docking) With Twin Rudders
by John Harries
Reading Time: 2 minutes
Next: Q&A Backing Out of a Bow-In Med Moor
Previous: Coming Alongside (Docking)—Backing In, Part 2
- Introduction to Coming Alongside (Docking) Online Book
- 10 Tips to Make Coming Alongside (Docking) Easy
- Coming Alongside (Docking) in 4 Easy Steps
- Rigging The Spring That Makes Docking Easy, Or an Alternative
- 10 Ways to Make Your Boat Easier to Bring Alongside a Dock
- Coming Alongside (Docking)—Manoeuvring in Close Quarters
- Coming Alongside (Docking)—The Final Approach
- Coming Alongside (Docking)—Taming the Wind
- Coming Alongside (Docking)—Backing In, Part 1
- Coming Alongside (Docking)—Backing In, Part 2
- Q&A, Coming Alongside (Docking) With Twin Rudders
- Q&A Backing Out of a Bow-In Med Moor
- 14 Tips for Coming Alongside Single-handed—Part 1
- 14 Tips To Come Alongside Single-Handed—Part 2
- Leaving a Dock Against an Onshore Wind—Part 1
- Leaving a Dock Against an Onshore Wind—Part 2
- Going Alongside (Docking) in Current—Fundamentals
- Going Alongside (Docking) in Current—Turning in Confined Spaces
- Going Alongside (Docking) in Current—Backing In
- Going Alongside (Docking)—12 More Tips and Tricks
Hi John
I have an Ovni 445 with twin rudders. I agree with you for the usefulness of a bow thruster , but also of the Maxprop propeller. I can turn the boat in one side “in her lenght” with the propeller only , when the wind is light (big windage…)
KR
Hi Dubuis,
That’s good news, indicating that twin rudders retain more prop walk than I feared. That said, I still think that a bow thruster is a good idea for these boats because of the lack of prop wash. (With prop wash I think you would be able to operate without a thruster even in higher winds, although that said, lifting keel boats can be challenging to dock.)
I’m hoping that you’ll cogitate, perhaps even ruminate, on coming along side with a heavy current, perhaps even one that’s in opposition to the wind.
If you’re interested in more specificity – we back our 45 foot Norseman along about 275 feet of before getting to our section of dock. The marina is in the mouth of a river that when the tide is going out gives us a 3 knot current pushing off the dock. The fairway is about 65 feet wide.
Hi Dartanyon,
Wow, that’s challenging! I will give it some deep cogitation.
When we had our 55 foot Aluminium lift keel boat designed the designers informed us that due to our request to have a minimum draft of 1,5 meters we had to have twin rudders…For the reasons obvious I was mordicus against it given the crowed entrances to locks and harbours in the Netherlands. They than came up with the solution to fit a, much smaller, third rudder behind the propellor. Jefa had done this a few times before and they designed the rudder geometry. We now sailed 15000 Nm in four seasons and are very happy with this configuration although it’s more complicated and costly… And yes we also have a bow thruster but only have to use it in unfavourable windy conditions.
Hi Douwe,
That’s interesting and good to hear it works. Like you, the complications would worry me, but then boats are all about tradeoffs and it sounds like you have balanced yours well.
Hi Douwe, is it the wonderful ship Stayer you are writing about?
Hi Svein, Yes it is… hopefully you and your wife are well and we can meet again in the near future!
Hi Douwe, we are fine sailing in Denmark in our small double- ender hoping to get home in the North before the sea ice close our harbour. I believe Stayer represent a new positive development in yacht construction with her tree rudders and many other solutions. I have observed Stayer enter rather difficult harbors in Loften and docking elegantly without using trusthers. However the rigg of Stayer is very tall. How is Stayer to handle when docking in much wind? When I saw her there was no wind.
I have observed that Stayer is extremely fast when sailing off-shore. Is she also comfortable off-shore? To mee Stayer seems like a unique modern construction: Good in shallow coastal waters, but also a fine long distance sailor. We would like to meet you again and discuss you experiences with Stayer.
For those considering a bow thruster, check out a Yacht Thruster. It’s an external unit, easy to install and able to be run for long durations because the motor is underwater-no overheating issues. It’s not speed robbing like a tunnel and requires one hole the size of a typical thru-hull. I was skeptical at first about having this torpedo shaped device hanging from the hull. But after three years, no complaints. One benefit, if the next owner doesn’t want it, it can easily removed and hole faired in a jiffy.
Hi Karl,
That’s interesting, although I have to say that the thought of adding such a thing to a hull that was not initially designed for it, particularly structurally, worries me a lot.
Just to be clear for everyone else, I’m not advocating for bow thrusters and in fact don’t recommend them, except for very special situations like twin rudder boats.
your observing that dual rudders are becoming more commonplace makes me wonder why ad this defeats the k i s s principle so important with sail craft especially…is also just that much more to incur damage…i think more than the std single rudder is jst asking for trouble
Hi Richard,
I agree. We are not fans of twin rudders here at AAC.
Hi John,
My limited experience with twin rudder boats has highlighted a few things for me.
Like most boats, you can usually get the stern into the wind even if it is against the direction of prop walk. Once you are in this orientation, it is relatively stable even without prop walk to help. I use this trick a lot on full keel boats and it works reasonably well here as well.
Backing down fairways can be a better bet as it makes changing direction easier and these boats usually back just fine. By getting steerage up in reverse out in the open, you deal with the harder to control direction change (assuming it is not a tailwind) out there.
Twin rudders is really unforgiving for people who drive as if they are using an outboard. It is crucial that you steer for the direction of water flow across the rudder and not whatever the engine is doing (this seems to be an issue for a lot of people based on my informal observation).
I learned something new in our single screw single rudder boat that should have been obvious a few weeks ago. I was trying to turn around our 36′ boat in an ~50′ wide creek that was turning hard to the left with the current behind us. I started my usual back and fill turn to starboard for our prop walk and the boat didn’t seem to want to turn. I then realized that the current on the outside of the turn was going faster so I switched to a port turn and the boat went around really easy despite being against the prop walk.
Eric
Hi Eric,
Great tips, as always, thank you. I had not really thought about the importance of realizing that water flow over the rudder will be different from the way the prop is driving for some time after changing the latter. I will need to incorporate that in a couple of future posts, so thanks again.
Hi John
As I do most of my sailing single handed, I am still crossing my fingers that you will make another video of you coming alongside singlehanded using the balanced-point aft running spring and tying everything off singlehanded.
Please 🙂
Kind regards, Peter
Hi Peter,
That reminds me that I need to do a single handed chapter, will do. Not sure a video will help a lot since all you would see is me making lines fast instead of me. Not a lot of value. Rather I think we need to explore getting the first line ashore and the dangers of getting off a boat that’s in gear.
Anyway, cogitating now.
Looking very much forward to reading that chapter. Happy cogitating ?
Hi John, did you already come around to that “single handed chapter”? I’ve just searched AAC and couldn’t find one except preparing for a singlehanded atlantic crossing?
Hi Ernest,
Not yet. I plan to get back to docking this summer, now that I have MC back in the water.
Hi all,
on two delivery trips with french raceboats (Archambault 35) I found that these boats -twin rudders, very wide stern- really ask for being backed into their slots. As Eric mentions, they are backing very well pretty much regardless of wind direction. Position one crewmember at the docking side of the pushpit, get a line ashore and power forward to pull the boat alongside. Works really well because of the wide transom and the resulting good leverage. The challenge comes when singlehanded, you have to be quick as the distance from tiller to the boat’s corner is rather long on this type of boat.
Hi Hans,
That makes sense. Another data point for my backing in chapter, thanks.
Hi John and Douwe,
On my brothers sail boat Flyer, where the prop is maybe 20ft forward from the rudder, I guess he would love to have a small 2nd rudder just behind the prop.
When we recently hauled out my motorboat, was surprised to see the (large)rudders could only swing 60 degrees from side to side, while the rudder indicators show about 100 degrees and yet it handles very well in tight spaces.
During my hi-school summer hollidays I worked on river Rhine barges, single prop and two rudders about 3 ft apart, but could turn the rudders close to 180 degrees. No bow thrusters in those days, but did have a bow (balanced) rudder that could be lowered and handled with a long tiller. As you know, now the maneuvring is (greatly?) enhanced with articulated rudders. Has that system found its way on pleasure boats?
Rene
Your focus is on larger boats with inboards. As multihull sailor, even the larger cats I’ve sailed or owned have always been outboard powered. With twin screws that far apart you have a whole world of tricks that I’m not going to get into. Some have had single engines. And what all of these have in common is trivial prop walk and no flow over the rudder.
But many small boats with outboards have something else they forget about all the time. The thrust can be directed by turning the motor. Unlike power boats, they have a rudder that works without prop wash.
One handy trick, say coming alongside on port, is to turn the rudder to starboard (tiller to port) while turning the engine to port and bumping reverse. The result is that the boat goes mostly sideways, slowly coming to a stop just touching the dock. Quite handy on a bulkhead with boats fore and aft.
There are other variations.
Hi Drew,
So true. The most manoeuvrable boat I have ever handled was a 28′ power cat with twin outboards. Even with a disabled 35′ sailboat lashed alongside I was able to work her into a tight marina and drop the sailboat off with no issues at all.
John,
I have concern that the balance point spring aft method may not work like it would with a single screw/single rudder vessel. In a normal setup the prop wash over the rudder and the rudder angle dictates where the bow and stern go when you are pivoting on that spring. A twin rudder will only be able to push ahead on that spring and not control any direction of bow/stern. In my opinion, I think a further aft spring would help with keeping the boat pinned to a dock as there wouldn’t be as easy of a pivot. Once pressed to the dock other lines could be made off the the thrust left off.
Am I making sense with this? Just to be clear, I’m still suggesting a quarter point for a spring, but only a little more aft for a single screw/twin rudder yacht.
Thanks for the very detailed posts on this too, by the way! Hope your cruising has gone well this season!
Ronnie
Hi Ronnie,
Yes, of course you are right, the balance point spring won’t work nearly as well with twin rudders. I should have thought of that, thanks for pointing it out.
As to moving the spring further back, that will help in some cases, but in others, such as a hard offshore wind, I think it could be a problem since it would be difficult to get the bow in, and there’s a good chance that as the spring is loaded the stern will come in with a bang.
What will work, is the balance point spring and a bow thruster working together, so I think that you point reinforces my thinking that for twin rudder boats a thruster goes from being an undesirable complication to a requirement.
John,
Good points, I didn’t think about a offshore howling you off. I do agree that a bow thruster is probably your only option.. Well, next to adding a third rudder or removing the two in lieu of one big one. I don’t think any of them is cheaper than the other once said and done.
Ronnie
Hi Ronnie and John,
I think that the magic spring line will still work well even without the help of prop wash. The thing that pulls the boat against the dock is the spring line itself (with a single rudder you can cheat and use prop thrust instead if the spring line has no angle to it) so the keys are getting an appropriate load on the line and having it pull in the correct direction. To get a load on it, you simply need to power against it, the more throttle you give it, the higher the load will be.
Getting the direction of the load correct is dependent on where each end of the line is attached to. Lines can only react tensile forces in line with them so the line needs to have an angle to the dock so that it can react your engine thrust and also pull the boat towards the dock. Too steep an angle and the stern will end up too far in, too shallow an angle and it will end up too far out (where the line is fore and aft also has a similar effect). For boats with shape like Morgan’s Cloud, you get a decent angle with a short spring that leads to a cleat right there on the edge of the dock. If the boat carries her beam aft, you might need to lead it to the far side of the dock finger to get some angle. Unless the boat is quite large, getting the exact right angle is not that big of a deal, you should be able to deal with a 10 or even 20 degree misalignment using fenders and by pulling on the bow and stern lines. The point is that you can hold yourself stationary indefinitely in approximately the position you want to be in while you sort out the other lines.
Even in the case where you have wind blowing hard off the dock and you start perpendicular to the dock stern-to, you should be able to get into place with this method, it will just take a minute. Because the line will be coming from the rail rather than centerline, there will be a torque when you motor ahead that will turn the boat so that the thrust will start to push the boat along the dock causing the spring line to pull you against it. In this extreme case, it is likely you won’t come in parallel so wide fender placement is critical.
Eric
Hi Eric,
That all makes sense and will be of comfort for twin rudder boat owners, thanks.
That said, I’m pretty sure that the “magic spring” will not be nearly as easy to use without prop wash on the rudder, as you allude to with your comment about fender placement.
In thinking about it, I’m guessing that the worst situation may be with the wind blowing hard onto the wharf. In this case with a single rudder we just steer hard away from the wharf to counteract the tendency (on most boats) for the bow to blow in and hit the dock hard as the boat comes in. On a floating dock this might not be too bad since the bow can land on a well placed fender, but on a high fixed dock the pulpit will be at risk and here, on a twin rudder boat, a burst from a bow thruster will be useful.
(I wouldn’t recommend a bow thruster for just this use, but given that twin rudder boats don’t have the benefits of prop wash in many other situations I guess I would stick with my recommendation in the post above.)
Hi John, Perhaps I missed it, but was hoping to find some hints in this book on docking related to a wind + current situation. We experienced this the other day and I made rather a mess of it…That’s no anchor roller, it’s a battering ram.! Wind was from ahead, current from astern , dock on port side. On retrospect i probably should have faced into the 2 kt. current rather than the 13 kt wind… thanks!
Hi Brian,
You remind me that I need to get back to this Online Book, probably be this summer.
On current, the key tip is that you can’t think of it like the wind. Unlike the wind, current does not pivot the boat in any way, but rather moves the entire boat. A good way to think about it is a model boat on a table with two people carrying the table: the motion of the table is the current.
So yes, in that situation it would be better to stem the current and have the wind on the stern. In fact, as I explain earlier in this online book, contrary what may people believe, it is actually far easier to dock a boat with the wind on the stern.