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"Twin engine" maneuvering with main and kicker
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jlastofka



Joined: 10 Jun 2007
Posts: 254
City/Region: Vista
State or Province: CA
C-Dory Year: 2007
C-Dory Model: 22 Cruiser
Vessel Name: Bossa Nova
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PostPosted: Mon Aug 06, 2007 12:06 am    Post subject: "Twin engine" maneuvering with main and kicker Reply with quote

On a whim today I tried using my 90 main and Hi thrust 9.9 kicker on my 22 cruiser to do the "big boat twin engine" maneuvering we all see around some slips and docks. To my pleasant surprise, it worked quite well, even though the engines are quite different and mounted very close together.

At very low speed, the Hi thrust kicker is similar to the main in terms of thrust vs throttle lever movement. I found it pretty easy to put one in forward and one in reverse and control the boat's turning rate by increasing or decreasing the spread between the two throttle settings. By moving both throttles forward or backward a little I could move the boat forward or backward while it was spinning in more or less one spot.

I'd never tried this before with any boat, but it seemed intuitive right from the start. I motored down the fairway between slips in front of the yacht club and spun the boat a couple times and parked alongside a dock, all without touching the steering wheel. I'd only been practicing about 10 minutes before trying this stunt in front of some friends. Too much fun....

I don't think I'll fire up the kicker every time I'm about to dock, but it's nice to have this technique waiting in the wings in case I need to use it.

Jeff
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hardee



Joined: 30 Oct 2006
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City/Region: Sequim
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Vessel Name: Sleepy-C
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PostPosted: Mon Aug 06, 2007 11:44 pm    Post subject: Twins - Yes Reply with quote

Jeff,
On the Sleepy C, we have twin 40's and On about my third time out I discovered that I can really steer by using the throttles in varying amounts of opposing setting, Idea (reverse on port, forward on Stbd) and it makes docking really easy. I have almost given up smacking the dock anymore. Wink Still envy the skipper who comes swishing in, a bit of an angle, hits neutral, spins the wheel, pops reverse, and steps off the dead still boat, 3 inches from the dock. Mr. Green Photo
Harvey
Sleepy C Moon

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TyBoo



Joined: 23 Oct 2003
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City/Region: Warrenton
State or Province: OR
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PostPosted: Mon Aug 06, 2007 11:55 pm    Post subject: Reply with quote

Quote:
Still envy the skipper who comes swishing in, a bit of an angle, hits neutral, spins the wheel, pops reverse, and steps off the dead still boat, 3 inches from the dock.


Hey! I did that once! Tried it hundreds of times and did it once.

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hardee



Joined: 30 Oct 2006
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City/Region: Sequim
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Vessel Name: Sleepy-C
Photos: SleepyC
PostPosted: Sat Aug 11, 2007 11:06 am    Post subject: Twins for Turning Reply with quote

Jeff wrote:
Quote:
On a whim today I tried using my 90 main and Hi thrust 9.9 kicker on my 22 cruiser to do the "big boat twin engine" maneuvering we all see around some slips and docks. To my pleasant surprise, it worked quite well, even though the engines are quite different and mounted very close together.

At very low speed, the Hi thrust kicker is similar to the main in terms of thrust vs throttle lever movement. I found it pretty easy to put one in forward and one in reverse and control the boat's turning rate by increasing or decreasing the spread between the two throttle settings. By moving both throttles forward or backward a little I could move the boat forward or backward while it was spinning in more or less one spot.


I am wondering if this maneuver which obviously puts a fairly significant torque on the transom is in fact dilatarious to the longevity of the transom. I am asking because I have become accustomed to doing this as a routine docking procedure. This may be the only downside I have found for having twins, (We are running Yamaha 40's x 2), CoolSmile or it may be a good reason to move up to the TC-255 Idea Wink With all the experience and expertise available here, I would like to hear the pro's and cons to the "big boat twin engine" maneuvering

Thanks and you all have a wonderful weekend.

Harvey
Sleepy C Moon
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Doryman



Joined: 03 Oct 2006
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City/Region: Anacortes
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C-Dory Year: 2006
C-Dory Model: 255 Tomcat
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PostPosted: Sat Aug 11, 2007 12:50 pm    Post subject: Reply with quote

I am totally spoiled by being able to maneuver my Tom Cat just with the two 150s. I know, I know, Bob says it is not as good as a "true" twin-screw boat, but I don't care. It is good enuff for me!

No downsides that I am aware of other than those endemic to twins in general (more maintenance, gas, drag, etc.)

Warren

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thataway



Joined: 02 Nov 2003
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PostPosted: Sat Aug 11, 2007 6:21 pm    Post subject: Reply with quote

I can assure you that when you are maneuvering with twins on a CD Transom that there is much less force than when you "put the petal to the metal" when you get up on a plane.

Manuevering is shifting at low speeds with a little throttle application and should not give any undo transom stress.

The issue with the Tom Cat--and the twins can certainly used to advantage--is that the hard chine hulls tend to act as keels when close quarter manuevering. The point I make is that with twin engine maneuvering on the TC 255, it is better with turning the engines to help with spinning the boat in its own length.

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Thataway
Thataway (Ex Seaweed) 2007 25 C Dory May 2018
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matt_unique



Joined: 27 Feb 2007
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City/Region: Boston
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PostPosted: Sat Aug 11, 2007 6:29 pm    Post subject: Twins Reply with quote

I love the maneuvering capability with twins. One of the commercial boats I run is a 32' 6 ton vessel with twin Merc 90 outboards. I sometimes have to maneuver in tight quarters and even though the engines are close together it will still turn on a dime. It just takes a little longer when the engines are closer together. I bet the Tomcat turns quick with the distance between the engines.
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Chris Bulovsky



Joined: 11 Mar 2004
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PostPosted: Sat Aug 11, 2007 9:39 pm    Post subject: Reply with quote

Jeff-
I have a 90 and a 9.9 as well. Using the 9.9 and the big one together sounds like something I need to try. Thanks for the idea! Thumbs Up

Wish I thought of that. 95% of my boating anxiety comes from docking with an audience. Its hard to look cool when the dammed wind is blowing the boat away from the dock.

Chris Bulovsky CoolSmile
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thataway



Joined: 02 Nov 2003
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PostPosted: Sat Aug 11, 2007 9:43 pm    Post subject: Reply with quote

One of the advantages of inboards and any counter rotating engines, is that the prop walking effect in reverse can be used to great advantage in turning with twin screws. Many of the Cats are rigged with the counter rotating engines "backward" from the usual inboard. So you have to keep this in mind when you are using the motors on the Tom Cats--and when walking the boat sideways with the engines.
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Hunkydory



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PostPosted: Sat Aug 11, 2007 10:29 pm    Post subject: Reply with quote

Chris Bulovsky wrote:
Jeff-
I have a 90 and a 9.9 as well. Using the 9.9 and the big one together sounds like something I need to try. Thanks for the idea! Thumbs Up

Wish I thought of that. 95% of my boating anxiety comes from docking with an audience. Its hard to look cool when the dammed wind is blowing the boat away from the dock.

Chris Bulovsky CoolSmile


Chris

I know all about that anxiety thing around the docks. I have tried using both motors and every other thing I could think of and still sometimes it would appear I knew what I was doing and others I would just plain lose track and out think myself or just go into overload and then just about anything could happen. I know I've provided plenty of entertainment at a lot of different docks. Then something just clicked this year and it finally seems natural like driving a car in traffic, or riding a horse in rough mountain terrain. Sure makes boating a more relaxing and fun experience.

Jay

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hardee



Joined: 30 Oct 2006
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PostPosted: Sun Aug 12, 2007 10:29 am    Post subject: Turning with Twins Reply with quote

I for one have a tendency to think it (the turning with twins) should happen quicker. I need to remember to just slow down and let the rotational forces at idle speed work. It does, and its cool CoolSmile when it does. Just have to remember BE PATIENT Mr. Green
Harvey
Sleepy C Moon
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hardee



Joined: 30 Oct 2006
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PostPosted: Wed Sep 16, 2020 1:33 am    Post subject: Reply with quote

So after 13 years of doing Twin engine, opposing throttle turns, my transom is still attached and solid, with no adverse affects. I have docked the "old fashioned way" a few times just so that if that bad thing happens and I have to come in on a single, it won't be my first time.

One of the things I enjoy doing when walking the docks is looking at the boats with twin OB's. You can always tell if they are docked using opposing throttles or spinning the wheel. The opposing throttle boats will all have their OB's in the centered position, not cranked off to one side or the other.

Harvey
SleepyC Moon

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Foggy



Joined: 01 Aug 2013
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PostPosted: Wed Sep 16, 2020 6:28 am    Post subject: Reply with quote

Boats with twin engine setups vary.
Operator's (aka "Captain's") ability varies.
Mother Nature (wind, current, wave action, visibility) varies.

So, if you need a constant in docking a boat, it is that
docking a boat is an art, not a science.

Aye.

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hardee



Joined: 30 Oct 2006
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PostPosted: Wed Sep 16, 2020 12:33 pm    Post subject: Reply with quote

aou contrare my friend.

All of the forces either being applied to the boat, or the forces the boat is applying are measurable. The forces applied by the boat (aka skipper) just have to be slightly greater than the ones applied by nature.

I will agree that some folks seem to do it more naturally than others, but it is applied physics none the less.

Harvey
SleepyC Moon
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Foggy



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PostPosted: Wed Sep 16, 2020 1:51 pm    Post subject: Reply with quote

Ah! In simple cases, probably so (see Ex (1); man conquers physics:

Ex (1): The challenge is a man has to put the apple in the bucket. Newton drops
the apple from a tree. If Newton is not high up in the tree, nor high winds, nor
earth quakes, nor dense fog, nor attacking beasts, the man can probably catch
the apple in the bucket. If some, or all, the complicating factors are present,
what are his chances?

Ex (2): A boat owner has perfected docking his boat in varied conditions from
mild to horrendous. Bravo! Now what are the chances he can dock a much
different boat (say, maybe your boat Wink) as smoothly as his own in 1 or 2
attempts on a nasty day?

Ex (3): Man has landed on the moon. Lots of physics involved here as well as
education, training, repetition, more training, practice, etc, etc, etc. Oh, don't
forget man has help from computerized systems to assist his endeavors.
Couldn't do it without those computers. Too much physics.

Aye.
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