Twin Power vs Single

G

grutledge

New member
OK I have read a few threads on this and people seem to have their opinions on using twin 40 or 50 HP engines or a single 90 (or similar) HP + a 9.9ish kicker. I am undecided on what the best option is. Here are some things I have heard and I would love to get opinions from C-dory owners.

Single + Kicker

- Good because you only have one large engine to maintain.
- Bad because people tend to not use their kicker so when they need them, they don't work.

Twin

- Bad because you cannot get counter rotating props in 40-50 HP so the boat tends to turn when you accelerate. Is this true? Can anyone confirm or deny this?
- Bad because you have two large engines to maintain approximately doubling your engine maintenance cost
- Good because they look cool :D
- Good because you always tend to use both engines so if one breaks down you can still get home at a reasonable speed.
- Good because you get better fuel consumption. At least that is what the performance spec say on the c-dory site. Anybody have any other experience on this front?

Any other pros/cons for these two setups?

Thanks for any input.

Glen
 
Glen,

Just run a search on this site of single vs twins and then arrange for a few weeks off work to read about this topic! Let's just say that it's come up before!

Best regards,

Nick
"Valkyrie"
 
For most of us, it is pretty hard to make a direct comparison...because we have either one setup or the other (not both!).

I experience NO tendency to "turn" with twin Honda 40's.

I bought the boat used, and paid to have the engines checked out and serviced the first year. Thereafter, I have had NO maintenance costs except for oil, grease and gas filter.

I have had 2-3 occasions when I was glad I had a second motor to get home (without much, if any, trouble).

I prefer to run both engines, even when trolling at the 10 mph speed limit on the Erie Canal. It makes for a quieter and smoother ride.

I feel I get quite good mileage. The engines are 1988. Across the past five seasons, I have averaged 5 mpg.

Hope this helps.
 
Wow - I had no idea there were so many threads on this subject. Sorry for bringing up old news. Obviously I am just getting into this game. But clearly this is a relevant topic. I will spend the next few weeks combing through the threads. Sorry to bother you.

Glen

PS I do appreciate the responses. Especially on the left turning issue! Thanks
 
I know a number of people say having two engines have saved them from having to be towed. What you might want to remember is if you have two engines you are twice as likely to have an engine failure.

I prefer one well maintained reliable engine but then I used to fly single engine planes and never worried about engine failure or wanted the complexity or cost of dealing with a twin.

And, this discussion will last longer than all of us and our engine(s).

Ron
 
I guess I'm new on the topic too. My thought is, twice the engines twice the gas. I know the math isn't exact but the theory works in my head.

I have to say, I'd love to drive a C-Dory with duals just to feel the differance. I'm not sure they can beat me on hours or miles to the gallon.
 
Hello Glen,

I'm a huge proponent of one main engine and a kicker. Your "pros" missed two important advantages/considerations in its favor.

- The kicker is always out of the water. So when you have two large engines and you strike an object in the water, you can easily put both engines out of commission. It happens more frequently than one would think. So with a kicker, you are at least assured that it will be there for you if you spin a prop or damage the lower unit.

- The C-Dory as well as the Marinaut are shallow draft boats. What happens if you venture into a foot of water such that you can't operate you main engine? It's happened to me twice in three years, because I love gunkholes. The main engine would not operate, because the water intake port would be out of the water. With a kicker, you can operate the kicker's shallow water drive in very shallow water. In the case of my (sold) CD 16 Cruiser, it could operate in less than a foot of water. Some may say that if you are in a foot of water, why not just get out of the boat and walk the boat to deeper water? On a sandy bottom, sure -- that would work just fine, but what if the bottom is muddy?

- Some will say that big engines are as reliable as a car engine -- you don't need a kicker; should something go wrong, all you do is call SeaTow or BoatsUS. I had five engine failures on the water with a brand new boat after its first 20 hours. It was a wiring harness issue that would cause the motor not to operate for several hours, then mysteriously clear up (of course, no one knew it was a wiring harness issue at that time.) On the first failure, I called SeaTow. They were great, and arrived within 20 minutes or so of the call. However, that was a bad situation, because my boat was in a large commercial river and drifting toward the spot where large ferry ships come in to dock. My anchor would not hold, because the riverbed was deep and made of hard rock. A kicker gives you an extra measure of safety to get out of situations in which you are immediately in peril.

As for maintaining your kicker -- it should be treated as importantly as your main engine. Since it most likely has a carburetor, you should treat the fuel and start it frequently so as to ensure it is there when you need it.

Finally, it is such a great feeling of comfort having a second motor on the transom -- out of the water and protected, to be there when you need it the most. Ahhhhhhh. That's why my wife and I decided to place a kicker on our new Marinaut. If you get a chance, see Les Lampman's photos of the heavy-duty kicker bracket on his Facebook account -- Folder Day 17 Pictures 1 and 2. In a few days, he will be installing a new Tohatsu 9.8 HP kicker motor. It will be configured so that the throttle and steering can be controlled from the helm. The thing that is really nice about this exceptionally light motor is that its controls: shift lever, electric start button, choke, throttle -- all are located directly at the front of the engine. Also, if you notice: Les installed a robust handle to grab hold while lowering or raising the engine. How easy can it get? Here is the link to his folder:

http://www.facebook.com/pages/Marinaut-Boat-Company-wwwmarinautboatscom/139546952799810?ref=hnav

Rich and Betty
 
Who are we kidding guys? There are a million threads because we love to talk about it :D

I have owned and used singles, twins, and quads. I prefer twins for my personal boat for the handling advantages and the redundancy of "main" power. It really boils down to your preferences. Engines with the same prop rotation will not turn you to the left. If you get a kicker - run it every time you run your main at least for a little while.

I had a good laugh with an earlier comment - right on the mark - with twins you are twice as likely to have an engine failure. BUT you are half as likely to be stranded.

The captain's here have collectively identified all the advantages and disadvantages. Good luck with your decision.
 
Nutty B":2mk21csw said:
I guess I'm new on the topic too. My thought is, twice the engines twice the gas. I know the math isn't exact but the theory works in my head.
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Click to expand...

The theory is wrong since the horsepower of each twin engine is typically around 1/2 of the single the same boat would be equipped with. Fuel consumption is based more on how much horsepower you're generating. One 100HP engine wide open will use approximately the same amount of fuel as two 50HP engines wide open. It will weigh a little less and hence that small difference in weight will have some impact on fuel mileage but it's negligible.
 
I've only had experience with a main and a kicker but I'm very happy with this arrangement. Earlier this month, the fuse to the ignition switch went out, we couldn't find it and we were literally in the middle of the San Juans. Our kicker took us approximately 20 miles to our safe haven. Ran like a champ, we had it tied to the main so we could steer from inside the cabin. The kicker served it's purpose and the it sipped the fuel. I probably burned 2 gallons on the kicker. It took longer but it was a flat, warm gorgeous day so no complaints.

On top of that, while fishing I think I prefer running off the kicker rather than trolling on a 40 or 50hp twin. Just my $.02.
 
One thing mentioned about the kicker was how much use it gets. I don't use mine much. I do fire it up at least once a month during the boating season. If you can run on it for a few hours, or use it for trolling, the better. Kickers seem to start up better when they're used once in a while.
 
I have had kickers on almost all of my outboard powered boats--never had twins on outboard boats, except the Tom Cat--and personally don't see the reason for them until you get up in boat size where you need the HP or a catamaran. The kickers were also used as dinghy motors, and thus used on a very regular basis--probably nearly as much as the main engine.

In fact many of the outboard engines are car engines (Honda, Suzuki etc). which have been converted for marine use.

The kicker needs to have separate fuel and electric systems. These are the items most likely to fail. Most "failures" can be rectified on the water by checking fuel and electric components of the system. To have a main engine catastrophic failure is extremely rare. But this is only one person's opinion.
 
From recent experience it is virtually impossible for the average user to diagnose and rectify an electronics fault on a modern engine without the factory tools. (Some "qualified" Honda mechanics armed with computer even get it wrong :amgry ) Even if you can maybe guess at it you will not have the simple diagnostic tool of being able to swap the suspect part with the "other" engine unless you have twins. How many of us are carrying (for example) an $1100.- ECM unit for a Honda or even a $380.- start relay. Both of which will shut your engine down for multiple reasons including straight failure of the non repairable part.

It is a personal choice but even with 135 HP left as my "kicker" I deliberately waited for a calm day to leave safe harbor and head for what I hoped was an engine shop (another story :amgry )

If the ECM had failed while in the middle of the strait of Georgia in significant seas as we had experienced two days before. I would have been more than happy to have 135 HP and 9 Kts available to me.

Just one experience and one viewpoint.

M
 
If twins are better . . .

Inside_Passage_2011_231_Triplets.jpg

These modest fellows were on the dinghy of a somewhat larger boat in the Petersburg, Alaska harbor this summer. There was a fishing pole in the dinghy (a 30? foot "Everglades"). Not sure about slow trolling for big Kings.
 
I sure would not like either the gas or routine maintenance bill for those suckers. :shock: :shock:

But let's see, doesn't routine maintenance help with reliability which is where this debate really centers??

Answer is impossible because it requires that you prove a negative. ie, what is the true cost of NOT doing maintenance. True for humans as well and mechanical systems.

Just to add a little more fuel to the flames, on another site someone recently commented ecstatically about getting fantastic economy of 10 mpg by going at hull speed and another replied by asking if he had added in the cost/hour for added maintenance on the basis that slower means more hours to get from A to B.
They had worked out that if you played by the factory rules you could be paying $4/Hr for maintenance. Now go add that to your fuel bill !!

Then you have to add in the question (do the math);- is getting 5 mpg at 4 Kts against a 3 Kt current is economical compared to 12 Kts at 2.2 mpg? (gets even better at 3 Kts against a 3 Kt current :D )

For me, only in a sailboat does that work.

Gotta love this never ending thread........

M
 
Really now, does it really matter? Only in your head. Which is where you are going to have the proclivity for the duplicit redundancy that the twins will offer. Yes I know, single engine, general aviation aircraft didn't even have kickers, just well maintained main (single) engines. However, I believe you will see a prevalence toward twins (or more) for off shore vessels. Yes, it is twice the maintenance (cost), but it is also twice the piece of mind.

The chance of taking them both out with a strike is there, but so is the chance that it will only be one, and yes a kicker up and out of the water is of benefit in that situation, if it runs and if it has the power to get you home.

I maneuvering in close quarters, twins will beat the pants off :monty a single, even on a 22. And yes, they do look good :thup :thup

And yes, this discussion will go on forever. It's a free country, and you can have your single :twisted: and I will keep my twins :smiled :smiled

:love :love my :smiled :smiled

Harvey
SleepyC :moon

IMGP1255.sized.jpg
 
Good point, Harvey (!), and I admire your ZEAL, but after 10 years of discussion/debate/ listing of pros & cons (" dissuade-o-dos"), I'm going on to bed, since almost no one is ever converted from Singularity to Dualism, or vis-a'-vis! (Beautiful photo, btw.)
ZZZZZZZZZZZZZZZZZZZZ!!! :clock :lol:

Joe. :moon :cocktail :wink :thup
 
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