Steering with twin engines: Differential Throttle Control

[rogerbum]

Harvey, I have tried the way you describe, with & without a loop at the end of the line to slip over the dock cleat. The problem we found is if the line is long enough to easily go over the dock cleat it allows the boat to go forward to far & without a loop, attaching to the cleat can take more time than the wind allows. That combined in the case of where we like to dock at Yellowstone Bridge Bay, with the strong afternoon winds pushing the bow into the electrical box mounted directly in between the two boat slips or another boat in the same two boat slip makes docking on the down wind side impossible for us especially with our large Manson Boss anchor. Rob's method of coming off the forward cleat using a measured line with a loop on the end could make docking where we prefer there possible under the normal afternoon southeast windy conditions. Docking on the other side of these two boat slips is easy with the wind holding the boat where it's wanted, but then if someone else has the other side veritably they will be hitting our boat in the process of their trying to dock.

Jay

Agreed. Harvey's method works fine if the slip is longer than the boat but is not so good if the slip is shorter. Also to be clear, I think Rob's using the "midship" cleat and not the bow cleat (which people might confuse when the terminology "forward cleat" is used). The midship cleat is great as it's far enough back from the bow to be on the wide part of the hull and hence forward motion with tension applied there will not pivot the bow in. If one uses a cleat closer to the bow, forward motion and tension there will pull the bow in. Jay - I'm sure you know this and meant the midship cleat (the one near the opening side windows on a 22) but I just wanted to make sure the method was clear to others. Aslo, with regard to bow the bow and the midship lines, I like mine to be as long as possible without being long enough to catch in the prop. That way if for some reason they get overboard, they are not a major issue.

In response to brooks&judy's post about not letting others on the dock handle your dock lines - another minor point about docking is making sure that your passengers are well trained about what to do and not to do prior to arriving at the dock - especially those who have boated before and they tend to want to be "helpful". I've had people jump off with just the stern line in hand and ruin perfectly good landing (the stern is the only end of the boat I really can control from the helm at slow speed) and I've had people make huge unsafe leaps to the when if they had waited a minute or two, I'd have the boat much closer. This is especially a concern when I've misjudged and am about to back out for a second shot at it.

When things are calm, I'd far prefer to just have new people on the boat stay out of my way. I'll bring the boat alongside the dock, and get out calmly with both the bow and stern lines in my hands. However, when there is a strong cross wind blowing me off the dock, I have to count on someone in the cockpit to help out. This past season at Ilwaco, I had to land to port in my assigned slip with a ~30kt wind trying to blow me off (and into a beautiful Ranger Tug in the slip to my starboard side). There were a couple of occasions where it took more than one attempt and on one of those occasions I had to shout to my helper to let go of the bow line while I backed out for the re-do. That was even after briefing the crew on what to do but not covering what to do if we didn't get on the dock in the first try. The situation wasn't helped at all by having a slip about 26' long and having a boat that's about 28' overall but at Ilwaco, I had to take what I could get.

 

[bridma]

When arriving at a C-Brat gathering there is usually a Brat or two on hand to help with the docking process. I have seen several boats approach the 'space' at 45 degrees going dead slow. The Brat handles the bow pulpit and walks the boat into the slip while the captain does a touch of reverse and/or shuts off the engine.

I made the mistake this summer of assuming every boater would understand this logic. I puttered into a tight slip at the 45 degree angle, a non-brat lady was there to catch me. What did she do? Nothing! and I hit the dock.
So, the message is simple. Keep on practising docking as though you are the only person around. Even non-boater passengers are a liability in their efforts to be helpful.

Martin.

 

[thataway]

The only time I use the bow cleat is for a breast line, once the boat is secured with the midships/aft lines. I might use it for "undocking" when I have a beam wind, and want to walk the stern off, in a tight situation, with a large fender to pivot on near the bow., but not when coming into the dock.

To clarify the "stop" when shifting. I like to have the prop not turning, before sifting in reverse. Bring the engine to idle, and shift to neutral. Then after a second or so in neutral, shift to revers, and then apply throttle. This does not imply that the boat's motion has stopped--in 80% of the cases, there is still forward way on.

We have all seen the "crash" reverse/forward to avoid a calamity. Something to be avoided. Docking at 3 knots is a bit faster than I am comfortable with. However, I was a passenger on a friends 57 foot sailboat, which had a folding prop (Martec). He came into the slip at about 3 knots--sort of "look at this"--right in front of the dining area at San Diego Yacht Club. The prop did not open in reverse, and he went right over about 8 feet of dock, sinking it, and hitting the boat on the other side!

Our rule, the person going to the dock waits until they can step off--not jump. At that point, I will usually have the midships line ready, and either over a cleat, or bull rail, or ready to hand to our crew.

I certainly agree--I try and avoid having someone who does not know what I am doing, take a dock line. They almost always try and tighten it up, which does not allow normal maneuvering.

 

[Hunkydory]

Harvey, I have tried the way you describe, with & without a loop at the end of the line to slip over the dock cleat. The problem we found is if the line is long enough to easily go over the dock cleat it allows the boat to go forward to far & without a loop, attaching to the cleat can take more time than the wind allows. That combined in the case of where we like to dock at Yellowstone Bridge Bay, with the strong afternoon winds pushing the bow into the electrical box mounted directly in between the two boat slips or another boat in the same two boat slip makes docking on the down wind side impossible for us especially with our large Manson Boss anchor. Rob's method of coming off the forward cleat using a measured line with a loop on the end could make docking where we prefer there possible under the normal afternoon southeast windy conditions. Docking on the other side of these two boat slips is easy with the wind holding the boat where it's wanted, but then if someone else has the other side veritably they will be hitting our boat in the process of their trying to dock.

Jay

Agreed. Harvey's method works fine if the slip is longer than the boat but is not so good if the slip is shorter. Also to be clear, I think Rob's using the "midship" cleat and not the bow cleat (which people might confuse when the terminology "forward cleat" is used). The midship cleat is great as it's far enough back from the bow to be on the wide part of the hull and hence forward motion with tension applied there will not pivot the bow in. If one uses a cleat closer to the bow, forward motion and tension there will pull the bow in. Jay - I'm sure you know this and meant the midship cleat (the one near the opening side windows on a 22) but I just wanted to make sure the method was clear to others. Aslo, with regard to bow the bow and the midship lines, I like mine to be as long as possible without being long enough to catch in the prop. That way if for some reason they get overboard, they are not a major issue

Thanks Roger for the clarification. I did mean the mid ship cleat when I described it as the forward cleat.

Jay

 

[Robert H. Wilkinson]

Also to be clear, I think Rob's using the "midship" cleat and not the bow cleat (which people might confuse when the terminology "forward cleat" is used). The midship cleat is great as it's far enough back from the bow to be on the wide part of the hull and hence forward motion with tension applied there will not pivot the bow in. If one uses a cleat closer to the bow, forward motion and tension there will pull the bow in.

Thanks for clearing that up - this is correct.

Another thing I forgot to mention is that this method is also very effective if you are coming into a finger slip with a larger boat beside you which can make it difficult to come in at an angle and necessitates approaching parallel to the dock. With wind blowing you off a parallel approach does not give you as much time to tie up as coming in at an angle and walking the boat sideways into the dock.

Also don't forget that the helm must be turned off the dock for this to work.

Regards, Rob

 

[Pandion]

Coming to a complete stop, as was suggested, before reversing one engine and going ahead on the other seems like more caution than I think necessary if your equipment is kept in good order.

This summer we took the boat from Everett down to Keyport, for lunch. As I circled around into the finger pier (without coming to a stop), I put my port engine in neutral, and approached the dock with the starboard engine at just enough speed to maintain steerage.

I pulled in perfectly parallel to the dock, popped the starboard engine into reverse and goosed it. The boat surged forward.

I was now only a few seconds now from hitting the end of the slip, so all of what followed happened in a flash. My next step was to pop the starboard engine back into neutral and my brain into self-doubt mode. That can't be right, I thought. I'm sure I had it in reverse. I'm sure reverse is all the way back. But the boat went forward. How could that be? Better try it again.

So, with a collision rapidly approaching, I put it in reverse again and gunned it ... and the boat surged forward and slammed into the dock.

The dock was padded and the boat struck right on the stainless bow guard. Remarkably, C-Dory and dock were entirely unhurt. There was, however, some indignant language from the first mate, who had been standing ready with the lines, and was nearly thrown off her feet.

There was a guy watching all of this from the dock, and he said, "I SAW him put it in reverse. He had it in reverse." I'm glad I had a witness.

What had happened was, the exterior sheathing of the starboard control cable had snapped free of its connection with the engine, effectively disabling the controls. That breakage had to have happened somewhere enroute from Everett to Keyport. Because I never stopped, I didn't know the starboard engine was stuck in forward, even when it appeared to be in neutral or reverse.

There are undoubtedly several lessons here. The first, for me, is that equipment that is in (apparent) good working order at the outset of a trip can fail during passage. The second, for me, is that coming to a full stop for just a second before docking, is not such a bad idea.

 

[rogerbum]

Coming to a complete stop, as was suggested, before reversing one engine and going ahead on the other seems like more caution than I think necessary if your equipment is kept in good order.

This summer we took the boat from Everett down to Keyport, for lunch. As I circled around into the finger pier (without coming to a stop), I put my port engine in neutral, and approached the dock with the starboard engine at just enough speed to maintain steerage.

I pulled in perfectly parallel to the dock, popped the starboard engine into reverse and goosed it. The boat surged forward.

I was now only a few seconds now from hitting the end of the slip, so all of what followed happened in a flash. My next step was to pop the starboard engine back into neutral and my brain into self-doubt mode. That can't be right, I thought. I'm sure I had it in reverse. I'm sure reverse is all the way back. But the boat went forward. How could that be? Better try it again.

So, with a collision rapidly approaching, I put it in reverse again and gunned it ... and the boat surged forward and slammed into the dock.

The dock was padded and the boat struck right on the stainless bow guard. Remarkably, C-Dory and dock were entirely unhurt. There was, however, some indignant language from the first mate, who had been standing ready with the lines, and was nearly thrown off her feet.

There was a guy watching all of this from the dock, and he said, "I SAW him put it in reverse. He had it in reverse." I'm glad I had a witness.

What had happened was, the exterior sheathing of the starboard control cable had snapped free of its connection with the engine, effectively disabling the controls. That breakage had to have happened somewhere enroute from Everett to Keyport. Because I never stopped, I didn't know the starboard engine was stuck in forward, even when it appeared to be in neutral or reverse.

There are undoubtedly several lessons here. The first, for me, is that equipment that is in (apparent) good working order at the outset of a trip can fail during passage. The second, for me, is that coming to a full stop for just a second before docking, is not such a bad idea.

Wow! That is indeed weird and I probably would have done the same thing (although I'd like to think I would have swapped to the port engine for the second reverse).

 

[Pandion]

Wow! That is indeed weird and I probably would have done the same thing (although I'd like to think I would have swapped to the port engine for the second reverse).

It all happened within 5 or 6 seconds. Literally a case of "think fast."

I did, but my first thought was "brain failure," not engine-controls failure.

 

[rogerbum]

Wow! That is indeed weird and I probably would have done the same thing (although I'd like to think I would have swapped to the port engine for the second reverse).

It all happened within 5 or 6 seconds. Literally a case of "think fast."

I did, but my first thought was "brain failure," not engine-controls failure.

I bet that would have been my first thought too, as for me, that's statistically far more likely than engine control failure.

 

[hardee]

From my observation this summer, the rate of twin engine boats (obviously this would be outboard only boats) was in the range of 25 - 35 percent. The percentage of those that were run, steering with differential throttle, (and this was only observed in the marina areas), about 10 - 20 per cent.

That is a pretty small group, which really surprised me, considering the advantages of using that "style" of maneuvering in confined, slow speed areas.

If you are running twin engines, I would highly recommend trying, at least, and practicing in a comfortable area, to gain proficiency and comfort with this system.

Harvey
SleepyC :moon

 

[NancyandBud]

Thanks to everyone who contributed to this thread.

As a sailor, I'm used to rudder control, even when the engine is not in gear.

I have to admit that our recent trip to KY lake showed my complete lack of knowledge about handling a twin engine power boat at the dock.

I have a lot to learn and practice. :thup

 

[Foggy]

Keep on trucking' out there.
There's always something new to learn.

Aye.
Grandma used to say, "A mind is a terrible thing to waste."
Or was that an old TV ad?