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Old 06-01-2018, 10:33 AM   #1
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Easy practice for twin engine operation

It has been my observation that people new to twin engine operation sometimes have trouble visualizing the effects of the props. Because they cant see the props learning the twisting effects is difficult for some

A simple way to help them understand what happens with different forward or reverse gear selection is to use a wheelchair.

It doesn't take long for people to figure out how each wheel in forward or reverse changes direction. Going backwards is also easy and so is spinning in place all techniques used on docking.

In a few minutes people can back into a parking space at an angle and know how to straighten out the motion at the correct time.
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Old 06-01-2018, 10:37 AM   #2
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Have also told people about the "thumbs" method.
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Old 06-01-2018, 12:23 PM   #3
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Another easy way is to visualize what happens with the shopping cart you're pushing when you push forward or backward on the handle.
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Old 06-01-2018, 01:03 PM   #4
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Another easy way is to visualize what happens with the shopping cart you're pushing when you push forward or backward on the handle.

A heavily loaded shopping cart is really good. Get a little momentum and then slow down with one hand or the other and its very similar to using reverse on one boat engine while moving forward. Also a great illustration of how the boat moves from a standstill if you put one hand only in "forward". Push only with the right hand and the cart will pivot, then stern will move a bit to the right, and the cart will start to move ahead and left. Just like a boat.
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Old 06-01-2018, 05:13 PM   #5
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I use parentheses

( )

Forward on the port side, bow moves to the right, back on the port side, stern moves to the right, and so on.

At least that works for me.
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Old 06-01-2018, 05:25 PM   #6
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The parentheses method is what I was taught many years ago. Works great, for me a least. My instructor said to visualize an arrow head on each point.
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Old 06-01-2018, 06:05 PM   #7
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The parentheses method is what I was taught many years ago. Works great, for me a least. My instructor said to visualize an arrow head on each point.


Lol, I walk down hallways in my house thinking of parenthesis as I turn corners!!! This method is what finally hit home for me with my twins.....now I just need the same for rudder and docking!
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Old 06-01-2018, 06:27 PM   #8
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I think that all of the above would be true, if there were no wind. Add 10 knots and it's a totally different profile.

I could argue to practice in zero wind, still water, turning... backing... aligning to a point or piling and see and experience what the controls do.

Now add a bit of wind and do the same, including holding at a point. When you add wind (or current) the angles and thrust can change a lot.
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Old 06-01-2018, 06:45 PM   #9
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Learned how to pilot a twin engine boat in the California Delta and San Francisco Bay where 10 to 15 knot winds on top of 5 knot tidal currents really make maneuvering fun. A little fore or aft throttle added to the equation does wonders. The ultimate test is going into a floating covered slip with a 5 knot current and 15 knot wind (in the same direction)running perpendicular to the slip and the 1/2 of your boat already in the slip is experiencing different wind and current dynamics than the other. Makes one very humble.
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Old 06-01-2018, 08:12 PM   #10
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Can't be too different from driving a tank with dual drive.
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Old 06-02-2018, 12:27 AM   #11
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Didn't everyone have one of these as a kid ??
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Old 06-02-2018, 07:23 AM   #12
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Learned how to drive a bulldozer when I was eighteen. Exact same principle.
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Old 06-04-2018, 01:53 PM   #13
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OK, I have never run a twin engine boat. So maybe it is more complicated than it seems?

To me, the effects of asymmetric thrust seems incredibly simple and self evident. The only complicating factor would the be effect of prop wash from each prop. That would depend on the direction of rotation of each engine and the hull shape. I must be missing something.
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Old 06-04-2018, 03:08 PM   #14
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You are correct however some people have a hard time visualizing that. Maybe you are just smarter than some others. []
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Old 06-04-2018, 03:20 PM   #15
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OK, I have never run a twin engine boat. So maybe it is more complicated than it seems?

To me, the effects of asymmetric thrust seems incredibly simple and self evident. The only complicating factor would the be effect of prop wash from each prop. That would depend on the direction of rotation of each engine and the hull shape. I must be missing something.
The asymmetric thrust concept is pretty simple when executed from a standstill. It is considerably more complicated when you throw in using combinations of forward and reverse to act on a vessel with momentum. Start a turn and adjust the path by using combinations of rudder, forward and reverse while the momentum continues to carry the boat. Throw in current and wind which affect all boats and you have a lot of calculations happening quickly in your head. Its easy and intuitive for some and very difficult for others.

I enjoy it and have become very comfortable but others find it difficult and stressful, at least early in the process.
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Old 06-04-2018, 04:40 PM   #16
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You are correct however some people have a hard time visualizing that. Maybe you are just smarter than some others. []

Ha! We all know that isn't the case.
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Old 06-04-2018, 04:44 PM   #17
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The asymmetric thrust concept is pretty simple when executed from a standstill. It is considerably more complicated when you throw in using combinations of forward and reverse to act on a vessel with momentum. Start a turn and adjust the path by using combinations of rudder, forward and reverse while the momentum continues to carry the boat. Throw in current and wind which affect all boats and you have a lot of calculations happening quickly in your head. Its easy and intuitive for some and very difficult for others.

I watched my dock neighbor come back to his home slip yesterday. He has a very easy slip to come in and out of (not a slip so much as a side tie) and the wind and current were helping to carry him to the dock. Even so, it was pretty impressive to watch how much control he was able to have over what his bow or stern were doing just by putting his engines into and out of gear at idle.
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Old 06-04-2018, 07:18 PM   #18
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Did any mention the "H" maneuver?
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Old 06-04-2018, 08:59 PM   #19
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Did any mention the "H" maneuver?
No, thought that was outlawed.
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Old 06-09-2018, 09:18 PM   #20
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I boated for 25 years with displacement hulls, one engine and vessels with more draft than average (commercial fishing vessels with large holds). I learned to dock and de-berth in all conditions, wind, currents (in some areas with over20' tides) and tight quarters.

Two years ago I purchased a sport boat with lots of superstructure and much less draft along with twin power. I have a very tight spot that I moor in which is the same one that I fit my past single engine vessel in. I now have to pay more attention to wind but the twin power is a dream to dock with. It did take a bit of practice to get the feel of this different vessel but the twins create a great tool to ease docking.

I understand that many have challenges docking their vessels. I have watched folks with very expensive yachts seemingly having no idea of how their vessels can be maneuvered. In my mind it is not intelligence that is the problem more just needing some training to develop the understanding of the controls then experience handling their vessel. Practicing around an open dock would be of help until they get a feel for their vessel.

I think there might be a market for a training program for folks that are new to boating or a particular new vessel?
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