Handling Question:moving sideways w/twins

I put the rudders amid ship on my sporty and never touch the steering again. Big props set deep and no keel at all helps a lot (in this circumstance). The big Allison gears shift pretty firmly and consistant, and to move directly sideways it takes a good bit of shifting. With about 3 foot forward movement and 3 foot aftward movement the boat will move about 6 foot to the side. Less for and aft means less sideways. With wind and current it becomes more difficult, obviously. A bow thruster would be nice.

Thanks Boatdriver. As I think about it, yours is the best, and only answer. It has to "all" matter. Rudder size, pitch, direction of thrust, draft are all to be worked with. Now, to have the moment when the wife is off the boat and I can play around with all this. She has little patience and less sense of humor at times like this.
Ted

Ted lyman said:

Thanks Boatdriver. As I think about it, yours is the best, and only answer. It has to "all" matter. Rudder size, pitch, direction of thrust, draft are all to be worked with. Now, to have the moment when the wife is off the boat and I can play around with all this. She has little patience and less sense of humor at times like this. Ted

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She might gain a lot more patience and sense of humor if she were the one learning how to do it.

Touche HeadMistress! Message received, lesson learned.
Ted

I found and printed an easily understood demystifying article on "Walking Sideways" some time ago. Written by Capt. Alan Ross Hugenot, headed "Two For The Road",a footnote to the copied page reads "102 SEA / JUNE 2004. No idea where I found it, those interested, with sleuthing skills, check it out.

Ted lyman said:

Touche HeadMistress! Message received, lesson learned. Ted

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Some openings are just irresistable! But on a serious note...

It's absolutely essential that spouses and SOs learn at least enough to be able to use the VHF and take control of the helm--if only to pull the throttle(s) back to idle and take the boat out of gear!--in case of emergency. Better yet, to be able to bring the boat to the nearest safe harbor and put it alongside a dock or T-head where an ambulance can take the stricken or injured person off the boat.

For 3+ years my husband fought a losing battle with bone cancer. He LOVED our boat! In the last year of his life, if I hadn't known how to handle it, we'd have had to become landlubbers.And it's a good thing I did because we did have a couple of "get him ashore and to an emergency room quickly" experiences that weren't life threatening yet, but could have become so. I've heard too many stories of wives who became totally hysterical...could only scream into the VHF mike, didn't even know enough to let go of the transmit button, much less how to stop the boat or even give anyone their location...when their husbands collapsed out on the water. Anything can happen out there to the oldest OR the youngest of us, and both of you need to be prepared to deal with it!

The Power Squadron is one of several organizations that teach "pinch hitter" skills to wives and SOs...that instruction--and more--is often available at rendezvous. Do yourselves a huge favor and give your admiral the encouragement--and courage if necessary!--to learn how to be a real deck hand and even a relief skipper. Her having those skills COULD save both your lives some day...meanwhile they're wonderful confidence builders that add a whole lot more fun aboard for her than only being your "step and fetch it!"

I'll get off my soapbox now...

BruceK said:

I found and printed an easily understood demystifying article on "Walking Sideways" some time ago. Written by Capt. Alan Ross Hugenot, headed "Two For The Road",a footnote to the copied page reads "102 SEA / JUNE 2004. No idea where I found it, those interested, with sleuthing skills, check it out.

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http://captainhugenot.com/?wpdmdl=175

Many other interesting-sounding articles in this site.

Excellent comment

HeadMistress said:

Some openings are just irresistable! But on a serious note...

It's absolutely essential that spouses and SOs learn at least enough to be able to use the VHF and take control of the helm--if only to pull the throttle(s) back to idle and take the boat out of gear!--in case of emergency. Better yet, to be able to bring the boat to the nearest safe harbor and put it alongside a dock or T-head where an ambulance can take the stricken or injured person off the boat.

For 3+ years my husband fought a losing battle with bone cancer. He LOVED our boat! In the last year of his life, if I hadn't known how to handle it, we'd have had to become landlubbers.And it's a good thing I did because we did have a couple of "get him ashore and to an emergency room quickly" experiences that weren't life threatening yet, but could have become so. I've heard too many stories of wives who became totally hysterical...could only scream into the VHF mike, didn't even know enough to let go of the transmit button, much less how to stop the boat or even give anyone their location...when their husbands collapsed out on the water. Anything can happen out there to the oldest OR the youngest of us, and both of you need to be prepared to deal with it!

The Power Squadron is one of several organizations that teach "pinch hitter" skills to wives and SOs...that instruction--and more--is often available at rendezvous. Do yourselves a huge favor and give your admiral the encouragement--and courage if necessary!--to learn how to be a real deck hand and even a relief skipper. Her having those skills COULD save both your lives some day...meanwhile they're wonderful confidence builders that add a whole lot more fun aboard for her than only being your "step and fetch it!"

I'll get off my soapbox now...

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Ever wounder why your wife is afraid to leave the dock. No one likes to feel helpless, encourage your wife to handle the boat and feel confident that she understands the basic safety systems, especially the VFH, and fire suppression. The life you safe may be yours.

Ted lyman said:

Thanks Boatdriver. As I think about it, yours is the best, and only answer. It has to "all" matter. Rudder size, pitch, direction of thrust, draft are all to be worked with. Now, to have the moment when the wife is off the boat and I can play around with all this. She has little patience and less sense of humor at times like this.
Ted

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That's probably the only way to figure it out as different boats may react vary differently to this technique. In fact, in the Captain Huguenot article mentioned above, the resulting motion he suggests is the opposite to the one most people in the post experience!
http://captainhugenot.com/?wpdmdl=175

I suspect what happens is that with this technique is that there are two, opposing, sideways forces acting on the stern: one from the forward-prop wash acting on the rudder and the other from the now combined "prop walk" of the two props rotating in the same direction.

So, in a boat like my GB50 with big rudders close to the props, the sideways force of the rudders overcomes the opposing "prop walk". In my previous boat, a GB42 with smaller rudders further from the props, the forces may have been balanced and the technique did not work. And in Captain Huguenot's case, it is the force from the prop walk that overcomes.

YMMV

Not sure if everyone is on the same sheet of musing...there's "walking" sideways and "sliding sideways"...


Most inboard twin boats and operators can walk sideways...sliding is an elusive animal.

scary said:

ever wounder why your wife is afraid to leave the dock. No one likes to feel helpless, encourage your wife to handle the boat and feel confident that she understands the basic safety systems, especially the vfh, and fire suppression. The life you safe may be yours.

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AMEN!

However, husbands are rarely the best "wife instructors"...they tend to focus more on protecting their precious boat than patient teaching, often turning their wives into nervous wrecks who want nothing to do with handling the boat. Best that she get instruction from a "neutral party, a friend--better yet another woman. Investigate what opportunites are available at your next rendezvous or even locally.

psneeld said:

Not sure if everyone is on the same sheet of musing...there's "walking" sideways and "sliding" sideways.

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Correct. Walking our twin engine boat sideways is so easy we generally let our dog do it while we take in the sights. Sliding our boat straight sideways is virtually impossibble no matter what combination of thrust and rudder is used.

Not sure of what the terminology is but I am referring to moving the boat sideways with little or no forward or backward movement or rotation.

Walking/sliding in certainly looks impressive when done well. But wouldn't a spring line work just as well, and be faster with less risk?

signed
Envious of those who can do it well.

AusCan said:

Walking/sliding in certainly looks impressive when done well. But wouldn't a spring line work just as well, and be faster with less risk?

signed
Envious of those who can do it well.

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I have occasionally been in situations where using a backward-leading spring from the bow in order to swing-out the stern did would not have worked.

Lats summer I was tied side-to a concrete pier in Zakinthos, Greece. After I tied-up a "megayacht" tied up behind me Med-style (perpendicular to the pier) as shown in the photo below. In the late afternoon a thunderstorm several miles away started bringing in a strong surge into the "port". And then the wind picked up pushing the boat against the pier, must have been a force 4. At this point the local boats started pulling away from the pier and anchoring in a protected area outside the port.

So with wind and the surge and the weather rapidly deteriorating we had to leave fast. But with the megayacht behind us and the concaveness of the pier we could not simply swing out the stern and reverse out as described by Marin and other. So I resorted to the sideways walk/slide by turning the wheel into the pier and using engines to swing the bow away from the pier. I had to use plenty of power but the boat was able to overcome the breeze and pull away more or less perpendicular to the pier, quite remarkable given the windage of my GB50.

The previous summer I was tied Med-style in a port in Montenegro (anchor off the bow and stern lines to the pier). We had a boat almost twice our length to one side and a strong breeze from the other side, pushing us into the long yacht. Remember we don't have the benefit pylons between boats in Mediterranean marinas and ports. But, by using the technique described, wheel towards the long yacht with inboard engine forward and outboard engine reversed, we were able to pull away and move forward without touching the neighbouring boat.

As mentioned, this technique works in some boats and not in others. And in some it works in reverse!

Luckily it works in my GB50 while it did not work in previous boat, a GB42.

I would prefer to have a bow-thruster but there are so many things on the list ...

Yet I have witnessed plenty of situations where even a twin couldn't get away from the dock without a spring line.


If the after bow spring isn't best...sometimes a forward quarter spring is the ticket.


A properly done spring with strong enough line and cleats can allow a vessel to use a huge amount of thrust and only advance the amount of stretch in the line which can vary.


After years of towing...learning that a line attached to a vessel can allow for so much better control...even when the vessel has no engine capability at all.

I agree with pneeld. I can walk my boat sideways, bumping gears. My goal is sliding perfectly sideways, without touching anything after getting set up, like on a rail I've seen it done, in a boat like mine. I refuse to admit my buddy was (now deceased) just better than me, but...
Ted

psneeld said:

If the after bow spring isn't best...sometimes a forward quarter spring is the ticket.

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Makes sense. If I understand this correctly, one backs out with the inboard engine in reverse and a doubled-up forward-leading spring from the forward quarter cleat?

Xlantic said:

Makes sense. If I understand this correctly, one backs out with the inboard engine in reverse and a doubled-up forward-leading spring from the forward quarter cleat?

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We've never tried pulling back against a line leading forward. We feel we get a much quicker and more positive response and departure by holding the bow in position with the bow line and pivoting the stern out with thrust against one of the rudders.

As described earlier, this means putting the dockside prop in reverse and the outside prop in forward and putting the rudders hard over toward the dock (as though steering into it).

By doing this the thrust of the outboard prop against the hard-over rudder is assisted by the propwalk from both props turning in the same direction. (This is assuming the typical counter-rotatingl prop rotation in forward of port:counterclockwise, starboard:clockwise when viewed from behind).

However with the twin, since one prop is developing forward thrust and the other reverse thrust, the boat will tend to not move either forward or backwards as the stern is swung out. Obviously a wind or current can disrupt this.

We've used this maneuver hundreds of times to get off a dock but even though the person handling the bow line always has a big fender hung down to put between the bow and the dock if necessary, so far it never has been. The prop in reverse has always countered the prop in forward sufficiently to keep the bow from actually coming in and contacting the dock as the boat pivots its stern away from the dock.

This would not be the case in a single where the only thrust being generated is from the prop in forward acting on the rudder to swing the stern out.

Xlantic said:

Makes sense. If I understand this correctly, one backs out with the inboard engine in reverse and a doubled-up forward-leading spring from the forward quarter cleat?

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I would use the outboard engine for more twist...but may depend.

The hardest thing with this, any angle puts the quarter or swim platform against the dock. You just have to adapt to that.

I use it a lot with a single and into the current with a wind pressing me to the dock. Especially if I have little room behind me.


With twins, and a lot of current...you may have to be pretty drastic with power to keep from getting impaled by the boat behind. The quarter spring makes it way less stressful.

Look up walking using inboard turning wheels, and twisting using outboard turning wheels.

To actually "Walk" requires inboard turning wheels and plenty big rudders (and YES they have to be used to work well)

looking over several posts on this forum it is clear that many are befuddled by the 'how and why'. But it does work on inboard turning props. but has to have large rudders, and practice.



To twist well requires outboard turning wheels and rudder use is just about useless (but usually does speed up the evolution incrementally)

Two distinctly separate functions.

Some boats with inboard turning wheels can barely walk because rudder size is so small that they can't utilize the walking ability of the wheels to propel directly sideways.

psneeld said:

The hardest thing with this, any angle puts the quarter or swim platform against the dock. You just have to adapt to that.

.

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Just curious---- What's the advantage of using this method, which apparently swings the bow out while putting the stern quarter/swim step against the dock over the "keep the-bow in place, swing the stern out 45 degrees or more and back out" method?

With the stern-out method one can depart the dock even with boats hard up to the bow and stern. There is almost no lateral movement parallel to the dock at all.

In a ripping current letting your bow swing out with the current then just powering against the current lets you crab straight out without getting near the boat behind you.


By backing out in a strong current and an on dock wind, you bow will swing very close to the boat behind you even if you do it well in some more extreme conditions.


I have seen many a pro capt tangle their bowsprit with the boat behind him...ugly

To check out how wheel rotation affects sideways thrust, when going ahead back one wheel full for a short thrust, just so the wash is coming out the side. Or better yet, when at a rugged dock and well tied up, Go to each side quickly and watch the results. On an outboard turning wheel all the wash will come out on the side you are backing on (sometimes at about 45o angle to the hull) On an inboard wheel some of the wash will actually cross over to the other side of the boat. You see this on a single screw vessel when tied up at a dock by leaving an engine in reverse and watching which side most of the wash flows to. Or better yet, on a flat calm day, with no current when at your mooring leave the engine in reverse for 10 minutes. what happens to the boat? It tries to circle the mooring. Why? Propwalk. That is how boats 'walk' directly sideways. they use the combined thrust of both props in addition to the rudder use to slew the boat directly sideways without even shifting the engines. You find the 'sweet spot' with the rudders and leave them alone during the evolution.

psneeld said:

In a ripping current letting your bow swing out with the current then just powering against the current lets you crab straight out without getting near the boat behind you.

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Good point. I can see that. So far we've never encountered the current situation you describe at a dock but that's a smart way to do it if we do. Usually we're either in relatively benign conditions or we have a wind that's blowing us onto the dock. Thanks.

Sorry, I'm only able to move sideways while moving back and forth. Moving to starboard is easier as we've a counter-clockwise propeller while going forward. The bow thruster helps immensely.

cappy208 said:

That is how boats 'walk' directly sideways. they use the combined thrust of both props in addition to the rudder use to slew the boat directly sideways without even shifting the engines. You find the 'sweet spot' with the rudders and leave them alone during the evolution.

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That's a great theory and I don't doubt it works with some boats. But we've been there, done that, and got the T-shirt with that technique and it does not work with ours. Or apparently with any twin-engine GB to read the discussions and comments from GB owners here and on the GB owners forum over the years whenever this topic comes up.

The closely-spaced props and a deep keel aft combine to defeat the notion of sliding directly sideways on props and rudders alone regardless of what combination of thrust and rudder one tries.

As psneeld pointed out earlier, walking and sliding directly sideways are two different types of maneuvers. Walking our boat sideways is no problem, bow, stern, bow, stern, etc. But sliding the whole boat directly sideways aint' gonna happen.

Having thrusters at both bow and stern makes moving sideways easy. I've seen it done dozens of times.

psneeld said:

I

The hardest thing with this, any angle puts the quarter or swim platform against the dock. You just have to adapt to that.

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If I understand the situation being described, I suspect it might be useful to consider a forward bow spring... doubled from the offside midship cleat (ideally a cleat slightly forward of center)... while backing out.

Offside engine in and out of forward, nearside engine reverse, spring paid out as necessary. Heavy fendering to protect the bow as it swings toward the dock.

Maybe. Probably a trade-off between protecting a swim platform, and not much control of the bow while backing.

-Chris

My point is...if backing away from a dock with lots of current and a wind string you against it....

You better back at full trotted, hope the props bite and don't cavirate, and pray. But I am talking currents most probably never deal with. If you can easily get 60 degrees from the dock, which I am saying in some conditions is near impossible without huge power use, then yes after bow springing works in several variations.

What I am suggesting is a ho-hum maneuver versus a panic one. It is even pretty easy single handed.