Single engine versus two - get home motor question

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igloo

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Considering a 75 foot trawler. Has a single 1999 375 horsepower Caterpillar diesel engine, model 3408. If anyone has had any experience with this particular motor, I would appreciate your input.

Main question is this. The boat has a 25 foot beam. My concern is a get you home motor if something happened to the main Cat. With a 25 foot beam, are there any recommendations for utilization of a get home motor, or would this be nearly impractical. Thanks for any help.
 
QC

QC

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Re: Single engine versus two - get home motor question

I know the engine well, but does not seem important to your question. Single screw displacement hulls are extremely efficient. I am not sure there is any economically practical solution other than a bracket and a monster OB diesel "kicker" :eek:

I can tell you that a 3408 is a V8, 5.4" bore x 6.5" stroke, 1099 CID, was used in Trucks, Machines, Gensets, Industrial and Marine applications.

Trivia time!!!! The 3408 shares a unique feature with Automotive V6s. Any cracks at it?
 
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TilliamWe

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Re: Single engine versus two - get home motor question

QC said:
Trivia time!!!! The 3408 shares a unique feature with Automotive V6s. Any cracks at it?
Click to expand...

Something about an even fire crankshaft?


I am with QC, it would take a really big outboard on a bracket to move that boat effectively. And unless you wanted to install a gas tank, it would need to be diesel powered. And I just read about those in Boating Magazine, they cost about $25,000 for a 250hp one!
 
The Famous Grouse

The Famous Grouse

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Re: Single engine versus two - get home motor question

I would post this question on one of the trawler-specific forms on the web. Trawlers are specialized animals and I think you'll get better advice by talking to those who actually own them.

Grouse
 
QC

QC

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Re: Single engine versus two - get home motor question

TilliamWe said:
Something about an even fire crankshaft?
Click to expand...
Ding, ding , ding, we have a winner. 3408s are 60 degree V8s and like V6s, to get them to fire evenly you have to have offset rod journals on the crank. Interestingly enough one of the problems with 3408s was broken cranks, but even with that very rare issue they were actually very long lived and dependable.
 
jay_merrill

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Re: Single engine versus two - get home motor question

I seem to remember a backup system that was powered by the vessel's generator. I believe that it was driven by a hydraulic system that made use of a coupling to the driveshaft. It could be disengaged and the generator's powerplant could drive either the genny or the driveshaft.

That said, I can't remember where or when I saw this - it would have been a long time ago.
 
QC

QC

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Re: Single engine versus two - get home motor question

Yes ^^^^^^

Even the largest sea going ships are starting to run single engines due to efficiency. Modern diesel and gasoline engines are extremely reliable if properly maintained so the need for a secondary propulsion unit has been reduced considerably.
 
Mike Robinson

Mike Robinson

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Re: Single engine versus two - get home motor question

jay_merrill said:
I seem to remember a backup system that was powered by the vessel's generator. I believe that it was driven by a hydraulic system that made use of a coupling to the driveshaft. It could be disengaged and the generator's powerplant could drive either the genny or the driveshaft.

That said, I can't remember where or when I saw this - it would have been a long time ago.
Click to expand...

I was going to mention this same thing. I think they are fairly common but I don't know much about them.
 
QC

QC

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Re: Single engine versus two - get home motor question

Good read here on this topic.
 
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