Singles versus Twins

Spike":1m0t5230 said:
As I have a single 115 and kicker it really does not pertain to me, but I am interested. How do you adjust "toe" on an outboard? Thanks
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You don't with a single, but it looks like you get that. On twins you can adjust the bracket (at least on mine) to make them so the are not perfectly parallel with one another.
 
T.R.
What bracket are you talking about? Do you shim one side of the motor as it hangs on the boat, or adjust using the tab under the cavitation plate? The mechanics of this intrest me. On my main I see no way of adjusting for toe. Maybe I'm missing something. Thanks
 
lloyds":e9cxaq9p said:
My engines are the same, and I am pretty sure they are right hand. I have tried to even out every other possible cause. I ended up adjusting with the tabs on the engines and got most of it out but it seems like with about 20 degrees of adjustment in the tabs it doesn't make for the most efficieint running. I might try the 3/16 toe in and see what that does.
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The trim tabs on our boat are set at at least 20 degrees, prolly more. Don't be afraid to add another 5 or 10 degrees. You won't know unless you try. The drag imposed by that little tab is miniscule compared to drag created by having to force the boat to maintain course.
Look at the size of Doel Fin or Bennett trim tabs that some of us shove into the water in order to make our boats more efficient.
 
Spike":thy7cflh said:
T.R.
What bracket are you talking about? Do you shim one side of the motor as it hangs on the boat, or adjust using the tab under the cavitation plate? The mechanics of this intrest me. On my main I see no way of adjusting for toe. Maybe I'm missing something. Thanks
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There is an adjustable tie rod between the engines that is a part of the steering linkage.
 
Just a thought. Having crossed the Pacific several times on the water and seeing ships with one propeller (although most trans- oceanic ships have twin or multiple screws) making the crossing. given the reliability of both 2 and 4 cycle motors properly maintained, the redundancy of twin motors may be more of a comfort factor than a reality one. But it really may depend on the nature of your boating. I guess I'm more confident in today's motors. Besides, twins gobble up space on the transom of a 22' complicating swim steps, steering and tabs, and simply are less economical on plane than a single engine. It is interesting to note that the Marinault is designed for a single engine; Les and his folks are comfortable with the single engine design. Then again, each person needs to scratch his fleas in his own way. John
 
Spike":1cewxjcb said:
T.R.
What bracket are you talking about? Do you shim one side of the motor as it hangs on the boat, or adjust using the tab under the cavitation plate? The mechanics of this intrest me. On my main I see no way of adjusting for toe. Maybe I'm missing something. Thanks
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Toe in/out is only used with twin engines. Think about feet and "pigeon toes". You can't do toe in/out with one main engine. The little trim tab under the cavitation plate is there to help offsite the single prop rotation and keep it on course at higher speeds where the tab has more effect.

Think of the front wheels of a car for toe in/out. Two wheels. If you were riding a unicycle, it would not apply.. :wink:

Charlie
 
Charlie
I knew that I did not need to worry about toe in or out as I have a single with a kicker. I was wondering how a person set and adjusted the toe on a twin set up.
Chester
I did not even think of the tie bar between the two motors. Next questions, Can you adjust the toe in or out force useing just the tab under the cavation plate, and do you have to adjust for toe in/out when the motors are mounted farther apart as in a Tomcat or a larger mono hull deep V where the motors may be farther apart than say a 25 or 22 CD. Thanks
 
Spike":2lk3ituo said:
Charlie

Chester
I did not even think of the tie bar between the two motors. Next questions, Can you adjust the toe in or out force useing just the tab under the cavation plate, and do you have to adjust for toe in/out when the motors are mounted farther apart as in a Tomcat or a larger mono hull deep V where the motors may be farther apart than say a 25 or 22 CD. Thanks
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The tab is there strictly to compensate for steering torque. Toe in is the geometric relationship between the motors. Deep V hulls require more toe in than shallower hulls such as C-Dory monohulls.
I don't know how varying distance between the motors affects toe in requirements. Some race boats use toe out for certain applications but that also is above my pay grade.
 
One thing to clarify is the definition of toe "in" vs "out". The way I understand it is, that for toe in, you adjust the front of the outboards outwards, more away from each other, as compared to exact parallel.

This increases efficiency and provides better steering centering by aligning them with the natural direction of water flow at the stern of the boat. You want the two wakes to merge correctly at some distance behind the boat at a given speed -- I do not know that speed/distance, it would vary by the length of the boat and the distance between the engines.

Is that what others understand?
 
Teleflex says:

"Toe-out = props farther apart than engine centerline (the prop is the "toe" of the foot, the engine gear housing is the heel).

Toe-in = props closer together than engine centerline (pigeon toe!).

Although I don't know the percent of single screw commercial ships--it is very high. Many of these can de-couple a cylinder and then use 11 instead of 12 (for example)--Some can be repaired under day. Most commercial fishing vessels are single screw.
 
I don't think that the benefit of two motors is to off set the reliability of modern motors. Today's motors are just to good. I think the benefit of twin motors is to off set the mistakes of captains running over stuff. In which case a single with a kicker is by far the better option.. yes I am bored and decide to chum today.
 
No matter, twins look cooler and more important! :roll:
 
starcrafttom":27rajgez said:
I don't think that the benefit of two motors is to off set the reliability of modern motors. Today's motors are just to good. I think the benefit of twin motors is to off set the mistakes of captains running over stuff. In which case a single with a kicker is by far the better option.. yes I am bored and decide to chum today.
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I agree with you Tom about the kicker, but as for today's motor's being "just too good" -- that's up for debate. Motors used to have simple carburetors, gasoline used to be gasoline (not ethanol added), and they had simple points -- everything was simple. Today's engines are highly complex and refined, and one could argue that a lot can go wrong. Perhaps they are too complex. My brother-in-law, for example, had a diesel inboard/outboard in his late model 26' boat that blew the computer three times when he tried to go from forward to reverse. Each computer cost $2,000. I was with him on one of those occasions when the engine just stopped in the middle of a channel. He got stranded two times. It's not like the old days with direct linkages of the transmission -- it's sensors everywhere: sensors to detect when the throttle is in reverse, forward or neutral, but when a sensor or a computer fails, you're up the creek without a panel. The manufacturer wouldn't do anything about it. He would have given anything for a good old fashioned direct linkage of the throttle to the transmission! I had 5 failures on the water due to an intermittent, failing wiring harness in my old boat. In another case, my engine in the old boat stalled in the middle of the river, because a black, nylon dock line in the water had wrapped around the prop. So many things can go wrong that it makes sense to have one engine free and clear of the water, and with a separate fuel supply.
 
Okay here's a new singles versus twins discussion... Had a need to remove the old osprey nest (Eagles and Canadian Geese broke it own)from the pole about 10 feet above the water and replace it with a nest about 6 feet above the water. Backed the boat up with the Twins , dropped the anchor, nestled the pole between the twins, cut it off of with an electric chainsaw. Would've been a lot more difficult with the single-engine. But not impossible.

Installed the prebuilt nest, the Male osprey arrived yesterday, he was a day early. He was very anxious and was carrying sticks all around us to start a new nest!

Will post pictures tomorrow. :mrgreen:

Charlie
 
Running on Lake Powell this year with the predicted low water, one of, "still crazy's." twin Suzies will be up enough to make sure that only one takes a hit if some log or whale rears it's head. It is nice to know that I'll still have a 50 hp to get me home rather than 15 or less. At Powell, altitude and density altitudes, a 15 hp kicker will be down by 30% or so in hp. But, I agree with the often posted, "twins just look cooler," as the very best reason to have twins.

Oh, and don't forget my own personal favorite: Would you want to get on a commercial jet that had a big engine on one wing and a little bitty one on the other? :):)
 
It's not just that twins look cooler, which they do, they look more important as well. :roll:
 
Oh Great ..... It's back :lol: :lol: :lol:

And what single and kicker can go from the entrance of the marina to the slip or launch ramp and never touch the steering wheel :?: :roll: :shock: :P :smiled

As a couple of friends of mine used to say, "Twins are twice the fun" :thup :thup

BTW, nice job Charlie :mrgreen:

Harvey
SleepyC:moon

JC_Lately_SleepyC_Flat_Blue_055.highlight.jpg
 
you know what they way in the south. "if your going to be impotent you should dress impotent.
 
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