Three Engines Versus Two

Pseudomind

Pseudomind

Active Member
Jul 1, 2008
2,122
Jacksonville, FL
Boat Info
2011 Hurricane with Magic Tilt Trailer
Engines
115 HP Yamaha Four Stroke
I am seeing more and more of this it seems, e.g Volvo IPS system, Why three engines? Seems to me a bit more overhead to contend with, what is the logic behind this configuration.

Thanks
 
If your buying a boat with three IPS systems i think the affordability of fuel will not be a problem...
 
Right. Why sell a twin engined boat for $150K when you can sell a three engined boat for $200K?
 
Zorba said:
If your buying a boat with three IPS systems i think the affordability of fuel will not be a problem...
Click to expand...


I am not interested in that, the cost but the logic behind going to three engines. Why not two engines two pods?
 
Pseudomind said:
I am not interested in that, the cost but the logic behind going to three engines. Why not two engines two pods?
Click to expand...

I think that reply was directed at my post. Just trying to inject some humor today, things have been dull lately…. Sorry.
 
It was directed at Hack. Now i look like and a-hole. thanks Hack for ruining my day, actually my whole year.

I'm sure the manuverability of three pod boats is amaznig. Also, although it would take some time to pay for itself the effeciency of pods over conventional propultion would probably warant the extra cost initially. That is just a guess though.
 
Seriously...3 engines would be required for either (1) more speed, or (2) more horsepower needed to push a heavier load.
 
Look I am not trying to hack anyone, just curious as to why three engines. Boatest.com has a demo of a 52 foot cruiser and they compare it to v-12 diesels. One option mentioned is fuel economy.

So if there is to be any hacking towards someone, someone else will have to do it, not me. I am not into a pi33ing contests over some question on a boat forum. :huh:
 
I remember reading an article about this last year and I wanted to get the big boat boys' opinion, but I forgot.

IIRC, the idea is 3 smaller engines weigh less than 2 big ones. So you use 3 engines to get the same HP as two big engines, but lose weight in the process. What the article didn't cover is the effect of the increased drag of the third pod. The concept made sense to me at the time. And having spent much of my life operating and maintaining equipment powered by diesels, I know that as long as the proper PM is done, the overall cost of ownership is relatively low. So 3 Vs. 2 wouldn't bother me from that standpoint. And inceased fuel efficiency was also cited in the article.
 
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Pseudomind said:
Look I am not trying to hack anyone, just curious as to why three engines. Boatest.com has a demo of a 52 foot cruiser and they compare it to v-12 diesels. One option mentioned is fuel economy.

So if there is to be any hacking towards someone, someone else will have to do it, not me. I am not into a pi33ing contests over some question on a boat forum. :huh:
Click to expand...

I would agree that it is a matter of HP needed to move mass. I know there is a 92' Lazzara out with a 4 engine/pod configuration. This is 2800HP pushing 136,000 lbs. Now I understand that the question was 2 vs 3 engines and so this yacht is disqualified due to an extra engine/drive. Sorry for the digression.

http://www.lazzarayachts.com/LSX92/techspecs.php
 
Zorba said:
It was directed at Hack. Now i look like and a-hole. thanks Hack for ruining my day, actually my whole year.
Click to expand...

So the humor is out on CSR? Great, let’s make all the postings about boats. You all must be a real hoot at the dock parties.
 
In keeping with the 3 smaller engines vs 2 really big ones, the issue may be more than engine weight. Pod drives, like stern drives, offer a different engine room location option than two big diesels with straight shafts. This gives the designer more options in floor plan layout. Also let's face it pod drives are 'in', so using three engines with pods has a higher geek factor than using plan old traditional marine diesels.

While there are commercial pod type drives, the software that controls them is geared more towards the commercial world, e.g. tugboat/ towboat maneuverability.

Henry
 
When you consider that many boats are offered with either 1 or 2 engines, and others may be offered with either gas or diesel engines, the choice may be a practical one, or merely personal preference. Where 2 engines may suffice, if a builder could sell a boat with 3 engines (at a profit) why not?
 
hack4alivin said:
I think that reply was directed at my post. Just trying to inject some humor today, things have been dull lately…. Sorry.
Click to expand...

No it was not directed at your post, I was just trying to obtain a somewhat plausible answer, before all the humor answers started. :smt021

highslice provided a fairly good answer as well as Henry, but remember to take into consideration, there has been much talk about with increased HP for the same size block diesel issues running higher RPM's the possibly of shorten the life of the diesel engine.

I was only looking for generalities of going from the typical two diesel setup to now using a three engine pod system.

Not an over all technical analysis.

:thumbsup:
 
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I talked to the guys from Wasatch at Lake Powell in detail, they used to sell Cruisers Yachts, and had a 55’ Express with trip-diesels. He said that the number one reason was to significantly increase top end speed on a heavy hull. I saw it in action and it really cooked. It passed everything but the fuel pump.:smt043
 
I think the reason is not technical, but it’s more marketing. In these times of global crisis, IPS offered the boat industry something new to give to possible customer. Problem was that the necessary power units were not available for larger boats. I guess that the three engine configuration will disappear as larger engines will be available with IPS. ZF has just announced a new pod drive which should be capable of handling some 1000HP. We will see…for the moment three engines mean to me +50% possibilities of a failure:grin:
 
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