running 2 motors

[mudslinging79]

what is the advantage of running a twin motor setup (side by side), does it double the horsepower, plane faster, what???

 

[Dhadley]

Re: running 2 motors

It doubles the horsepower on the boat but it doesn't necessairly double the speed. It does double the gearcase drag. And the weight. An engineer told me the percentage of additional thrust once but I don't rember what it was exactly. I do remember I thought it was pretty low though. I do remember he said the 3rd motor added 5%. Not sure I buy into that though.

I've always said, the only reason to run two motors is because there wasn't room for three.

 

[Titanium48]

Re: running 2 motors

Redundancy. If one outboard dies in the middle of nowhere you have another to get back with. A kicker could do the same, but half of a twin setup will usually be powerful enough to plane the hull.

 

[QC]

Re: running 2 motors

Also great for around the dock as a boat with twins can usually be spun 360 degrees within its own length by putting one in forward and one in reverse.

 

[wbeaton]

Re: running 2 motors

You have all missed the most important factor - coolness.

 

[jay_merrill]

Re: running 2 motors

The primary advantage of twin engines is redundancy in power source and 12VDC supply. The main disadvantages are increased fuel consumption for a given power level, and higher maintenance costs.

Ten years ago, I think most people would not have considered the fuel issue to be a prime determinate in regard to powering with one engine v. two. These days, the decision is obviously more complicated. To make things easier, I suggest considering where most of your boating will be. If you boat in protected waters, with lots of other boats around, twin engines probably aren't needed. On the other hand, if you operate your boat offshore, or in very remote locations, twins might make a lot of sense.

 

[godspede619]

Re: running 2 motors

Personally Id rather have one outboard and a decent little kicker for trolling and being stranded. The way these new outboards are being produced makes it redundant to be sportin twins... double the maintenance and burns more gas even though the twins are pushin a lighter load.

 

[coolguy147]

Re: running 2 motors

ur wallet will empty faster?

 

[slasmith1]

Re: running 2 motors

. The main disadvantages are increased fuel consumption for a given power level, and higher maintenance costs.

This is not true in every case. My last boat had a single 5.7 and weighed 4000lbs dry and about 5000-5200 as normally used. I burned about 9-10 gph at 26mph 3200 rpm.

My current boat weighs 12800 lbs dry and about 15000-16000lbs as normally used. I now burn approx 11-12gph with twin 5.7gxi dp drives at 30mph at 3200rpm.

when you consider the weight and speed differences I would definitely say that the twin setup is more efficient.

 

[QC]

Re: running 2 motors

But slasmith, you have no data with your current boat as a 500 bhp single . . . and you have no data with your old boat and a more modern engine (EFI). And I suspect that the hulls are sigfnificantly different.

Singles are always more efficient if power is sufficient for the job. Even the largest ships on the water are gong to singles. Check out the Emma Maersk

BTW, I love twins.

 

[slasmith1]

Re: running 2 motors

But slasmith, you have no data with your current boat as a 500 bhp single . . . and you have no data with your old boat and a more modern engine (EFI). And I suspect that the hulls are sigfnificantly different.

Singles are always more efficient if power is sufficient for the job. Even the largest ships on the water are gong to singles. Check out the Emma Maersk

BTW, I love twins.

Think how cool that ship would be with twins 218,000bhp
Yes the EFI is great and there are some other differences and I love twins too, mostly for the low speed handling in larger boats though.

 

[marquette]

Re: running 2 motors

when you set up a boat for twins do you use 2 motors of max hp or 2 motors that equal max hp? i mean if a a boat is rated for 200hp do ou use 2 100 hp motors or 2 200 hp motors?

 

[QC]

Re: running 2 motors

2 motors that equal max ratring. In your example, 2 x 100.

 

[Frank Acampora]

Re: running 2 motors

Having twin engines is a lot like having twin women: They are a lot more fuss to set up, they cost you a lot more, but they are definitely worth it.

Believe me: If my boat had room on the transom, It would have a matched pair on it.

 

[wbeaton]

Re: running 2 motors

Having twin engines is a lot like having twin women: They are a lot more fuss to set up, they cost you a lot more, but they are definitely worth it.

Believe me: If my boat had room on the transom, It would have a matched pair on it.

Too funny!

 

[haskindm]

Re: running 2 motors

You may need twins to obtain the maximum horsepower that you want. I don't think anyone builds a 500 HP outboard (yet), so in order to get 500 HP you would need to mount twin 250 HP. To get 750 HP you would need triple 250's. That said, a single 300 would be faster and more efficient than twin 150's. The twins would have more drag and more weight for the same horsepower. There is the added reliability and manueverability of a twin set up that has to be balanced against the additional initial cost, maintenance cost, and fuel cost of a twin setup. But I agree, they really look cool! Isn't that what it is really all about?

 

[tmcalavy]

Re: running 2 motors

And they sound marvelous at WOT...quite a growl.