Docking with twins

[kolive]

OK, I realize the title could be warped an infinite number of ways but I was reading the posts on twin engines or singles and DaveS of Sea Shift said this; " Usually, when I "dock", I position both engines straight ahead and keeping my hands off the steering wheel, work the throttles alternately forward/reverse to spin the vessel into position. " I have never run twin engines and am curious as to how this works. Is it like having the control of larger twin engine boats that have the manuverability to have one in forward and the other in reverse to navigate tight quarters? It sounds like it does some things a bow thruster can do for single engine boats. I hope this doesn't sound to dumb, but I really don't know. My current boat has a single engine and until I get my CD I won't really be able to try it.

1st edit addition
So as I think more about this and ponder it I don't see how this works with both motors being so close to each other. I must have this ALL wrong. HELP!!!!!!!!!!!!!!!!

2nd edit addition
Can someone point me to a photo of the helm area for a throttle control setup for twin engines?

Keith
aka, can't wait for the SBS
"Work is Overrated"

[El and Bill]

Keith --
With our dual engines, we can put one in forward, the other in reverse, with same rpm, and Halcyon turns 360. Reverse which engine is forward and which reverse and she turns 360 the other direction. She pivots roughly around her midpoint. Therefore, any variation on which is forward, reverse, or neutral can steer the boat very effectively in tight quarters. Does this help?

[kolive]

Yes! That helps me a lot. That is what I was envisioning but had not seen this move yet. I have done this aboard a trawler but not a twin outboard. I like the sounds of this.

Keith

[DaveS]

It's pretty slick when you cruise in a tight marina and wish to turn to proceed the opposite direction. I'll idle down the channel with one engine in forward gear, the other engine in neutral, get to where I wish to turn, then place the neutral engine in reverse and spin around in my own boat length and motor back out. Not that you can't turn around with a single engine, I find that it is just easier this way.
I get spoiled maneuvering with the twins and then when I'm running our Fire/Rescue boat with its' single 225 Yamaha, I have to remember how I used to do it...

(Bottom line.....I just find twins to be more fun......even dated twins in high school.... ).

[Sea Wolf]

kolive-

Twin engines do make it easier to maneuver, such as docking.

This works moderately well when both engines are fairly close together, as in the CD-22, or the CD-25.

Greater separation of the engines, as in a catamaran, like one of the Tomcats, increases this advantages quite a bit, as does counter-rotation, which evens out the tendency of the screws to favor (walk) one direction.

Maneuvering direct drive inboards (straight shafts) is somewhat more difficult, as the drives are locked fore-aft, with only the rudders to steer, and in reverse at low speed, a rudder alone has very limited steerage.

"Steering" by only shifting engines into F-N-R independently is best for the direct drive set up, but can also be done with outboards or I/O's (stern drives).

The absolute best maneuverability is to use the outboards or I/O's in the F-N-R "shift steering" method combined with the steering wheel, which can direct the thrust of the engines off the centerline as needed. (This is known as "vectored thrust") One engine can be engaged in gear at a time or both can be engaged. They can be one or both in forward, one or both in reverse, or one in forward and one in reverse, etc. Don't forget to steer, too!

Using the engines as described in the last paragraph takes some forethought, but increases maneuverability greatly.

Bow and stern thrusters are useful on really big boats, especially those where the tonnage can do major damage to a dock or pier.

Some modern tugs have a I/O style leg in the middle of the hull which can swivel 360 degrees to get their job done.

Hope this helps!

Joe.

[CAVU]

A few times while using the differential thrust technique I have had my temperature warning horn sound-as if the water flow to one engine had been disrupted. Bringing both engines back to idle instantly stops the horn. It has only happened when using a little higher rpms like when I want to make a quicker turn. Has anyone else had this happen? I don't recall if it is always the same engine since it doesn't happen very often. Maybe one water pump is weak-but both have a good pee-stream.

[Hunkydory]

There has been times I've been able to control as Dave S and El and Bill have described. Both engines straight and then maneuvering with throttles, but with a little wind and current in a tight place have had to quickly resort to adding more control with steering as described by Joe. The majority of the time I've found for me its better to just plan on using the combination steering wheel and forward reverse throttle control. This is especially so since adding hydraulic steering and the old fashioned suicide knob.

Jay

[patrick and linda]

JUST THOUGHT I'D THROW IN MY TWO CENTS. WHEN OPERATING LARGER VESSELS, WITH OR WITHOUT TRUSTERS, I'D ABSOLUTELY EMPLOY THE REVERSING OF ONE ENGINE AND THE FORWARD GEAR OF THE OPPOSITE ENGINE. NO PROBLEM THERE. HOWEVER, REGARDING MY LITTLE 22' C-DORY TWIN 40HP ENGINES, I TEND TO OPERATE THAT AS IF IT WAS A SINGLE ENGINE VESSEL. THE TWIN ENGINES ARE MOUNTED SO CLOSE TOGETHER, I JUST DON'T GET THE RESPONSE I'M ACCUSTOMED TO WHEN DEALING WITH THE BIGGER BOATS. SO, IF YOU'RE ACCUSTOMED TO THE SINGLE ENGINED BOAT MANEUVERS, I WOULD JUST CONTINUE WITH THAT TYPE OF HANDLING PROCEDURE.
I HAVE A GOOD FRIEND WHO SEVERAL YEARS AGO, PURCHASED A NEW 78' HOUSEBOAT. THIS WAS BY FAR THE BIGGEST BOAT HE HAD OPERATED TO THAT POINT. I ASKED HIM WHAT WENT THRU YOUR MIND THE FIRST TIME YOU HAD TO DOCK THE BOAT BACK INTO THE SLIP. HE SAID, I JUST KEPT TELLING MYSELF, IT HAS TO GO INTO THE SLIP, IT HAS TO GO INTO THE SLIP.
I GUESS AFTER ALL, THAT'S NOT A BAD APPROACH.
BEST REGARDS ALL
PAT

[Sea Angel]

Ah , yes another 2 scents worths...

The Sea Angel has twins [90hps] and there are several pix of the setup on this site. I have have found a couple of fine points of the CD25 that keeps me on my toes when docking at my marina. I have to back into(North) a slip with a cross tidal current that can get up to 3+ kts and a cross wind that comes down the creek that run East -West.

Here the procedure is to back into the oncoming current parallel to the bulkhead. This is normally done at or just a little above idle with both in reverse.

I try to keep abt 3/4 of a boat length away from the finger dock before I start my turn into the space between the docks.

By using the dock side motor from R to N, then F to pull the stern into the opening. I use this dock side engine for steering; R-N-F as needed.

By using only the one throttle you less to keep track of; especially with the blind spots from the helm looking aft. Slow and steady is the rule.

The lower units follow the current and will pull me to the upstream side of the dock.

This whole time period is when you have to decide whether the wind is going to grab the sail area of the cabin and it will change your pivot point if you are not careful; especially if the wind and current are opposite and the wind gusty. I have aborted many landings, but yet to have any hull marks by using this approach.

Without counter rotation props you will find the CD will respond better in one direction than another. To tell which will let the cat out of the bag. Go out there and find an open spot and PRACTICE, PRACTICE and practice some more. Just to give you a taste - when I make a WOT hard turn to port, my CD digs in and squats in a nice tight turn. However when I turn to starboard at WOT I feel like I'm riding a flat pancake that wants to skip across the bay sideways and I don't feel comfortable doing this unless the water is flat. This is even with full fuel [110 gals] tanks. The 4 blade SS props either lifts my stern out of the water or digs a hole in the turns. They are great for the low end torque needed for dock side maneuvering.

There are many great suggestions on this site by many vets who could tell you stories that will make your hair stand up. As an example - I almost drove my anchor through the side wndow of a new Grady White when a micro burst caught me coming away from our fuel dock one afternoon. Glad I had all that power to fight both the curent, the following winds and the parachute action of my camperback. Again I must keep planning for Murphy's actions when I'm out there and how to foil him....

[patrick and linda]

Sea Angel
HI ART,
I ENJOYED YOUR STORY REGARDING THE NEAR MISSED ANCHOR IMPELLING YOUR NEIGHBORING GRADY WHITE. THIS ONLY HAPPENS WHEN THE DOCK IS LOADED WITH PEOPLE, ALL REQUIRED TO WITNESS YOUR MISFORTUNE.
I LIKE TO SAY, THERE'S NOT A BOAT IN THE HARBOUR I CAN'T OPERATE, AND, THERE'S NOT A BOAT IN THE HARBOUR I CAN'T WRECK, AS WELL.
MY WIFE AND I BELIEVE IT'S A GOOD DAY ON THE WATER WHEN YOU ARRIVE BACK AT THE MARINA AND YOUR DAY HAS NOT CAUSED ANY INJURY OR PROPERTY DAMAGE.
AS ALWAYS, BEST REGARDS ALL,
PAT

[Sea Angel]

Thanks for the memory jog, Pat.
When I was flying as a crew member, RADAR & SONAR position, in the Navy's old S2F, I had a skipper who often referred to all his landings as controlled crashes. As long as the the 2 pilot coolers [props] were moving air, the pilots were cool. Let them stop and watch them sweat. I had that happen one too many times over the Atlantic in both the winter and summer.

At least here on the CD25 when one of my skipper coolers [Hondas] stops, I can have a softer landing. {I didn't say that I will.} I did have that happen the last time out while I was backing into the docking space, THAT was a momentary thrill. Glad the Honda had a quick start to get things back under better control, for I was committed.

Yes, Pat, every time I go out and come back safely is a blessing, especially if all I have lost is weight from fuel useage.

[thataway]

I agree with Capt Pat. Having operated larger inboard boats with twins vs outboars, or even the Tom Cats, the inboards responded better with the twins, and I tend to drive the Tom Cat 255 with the outboars, as I do conventional outboard boats--that is is steer the boat in reverse or foreward with the prop thrust steered to the direction I want to go in.

The Tom Cat's slab sided hulls do tend to act as keels, and there is less walk than one might expect. However one can both turn the boats and walk them with the prop walk.

[Sawdust]

OK,

The old coot (better words available) has lurked long enough.

By placing your rudder (s) amidships and jocking with throttles you are losing a very import part of the maneuvering capability of your twin-engined boat (any kind). The vectored thrust you get from your engines when maneuvering in tight situations can be improved may times by using your rudders too. This works equally as well with non-vectored thrust boats. With counter-rotating props it's even more effective to add rudder to the mix.

Unbelievers should give it a try. When I was teaching this stuff I'd start the students with rudder amidships -- then graduate to the next phase.

Doubters can come up this way and vist

Really ticks me off not to be able to come to Seattle and meet so many old friends -- and of course meet new ones. And please treat Les gently.

To all the gang, CHEERS!!!!! , and have fun.

Dusty