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Bob On This
USA
175 Posts |
 Posted - 12/30/2008 : 11:34:29 AM
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I am looking at buying this boat, but I keep reading about the fuel
consumtion being around a mile per gal. Is there something about these boats? I would expect numbers like this for a 30 plus boat with twin 454's maybe.
Any advise?
Thanks
Bob
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woodboat
Canada
131 Posts |
Posted - 12/30/2008 : 2:31:49 PM
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| From my experience, 28' - 35', expect about one mile per gallon total with twin engines regardless of engine displacement or manufactuer of the boat (assuming same general hull design). Actual consumption will vary of course depending on weather (waves/wind), hull cleanliness, engine condition, speed and also vessel load etc, however larger displacement engines do not have to work as hard as smaller engines and so burn less per given speed (throttle setting is reduced). Now that would be all imo of course... |
Edited by - woodboat on 12/30/2008 2:33:37 PM |
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Bob On This
USA
175 Posts |
Posted - 12/30/2008 : 4:48:15 PM
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Thanks,
They are 305's BTW,,, Opps
So, in your option, even if repowered with a couple 3.0 inline 4's and traveling at hull speed, we could expect the same consumption?
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woodboat
Canada
131 Posts |
Posted - 12/30/2008 : 11:38:44 PM
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Well no, probably not... at hull speed which is roughly 6 to 7 knots (1.34 X the square root of LWL) fuel mileage with a couple 3.0 inline 4's would probably improve by as much as 50% over the 305's imo. I do feel the 50% would be the outside max though I am certainly not an expert on this type of thing. However benefits that V-8 power brings will be lost in such a scenario.
Of course you caught me in my earlier reply as I was thinking of V-8 power when writing about essentially similar consumption with twin engines regardless of engine displacement or manufacturer... |
Edited by - woodboat on 12/30/2008 11:40:18 PM |
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Bob On This
USA
175 Posts |
Posted - 12/31/2008 : 2:54:47 PM
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Thanks Woodboat,
I was not tring to trip you up. I am looking at this boat in hopes of doing the "loop" some day,
and would (IMO) not need 500+ HP. Do you know of anyone that has done such a repower?
I was looking at a 28' Glasply with twin 470's that seemed to be just what we needed, but others
have now spooked me about the old 470's.
Thanks again
Bob
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woodboat
Canada
131 Posts |
Posted - 12/31/2008 : 7:55:46 PM
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There are several on this board who are much more knowledgable in the field of swapping power in these boats, perhaps after the holidays they will chime in.
Some interesting reading at this site... http://www.marine-engines.net/topics/001211.html?motors
here is a quote: "These are a decent motor, they have good power to weight, and are reliable, except for the aformentioned charging system. They are based on half of a Ford 460 v8. The head casting is Ford/lincoln 460, as are the rods, and piston dimensions. The block and crank and cam is built for Mercruiser. The 165 has the larger 4" heat exchanger for better cooling. They take the same tune up kit (pts,cond,cap,rotor) as the MCM Chevy 4cyl engines with a delco distributor. It was also available with a 4bbl carb as a 180hp-------------"
Finding a suitable boat with the desired power train would likely be the easiest solution and maybe the most cost effective unless you can do it all yourself.
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Bob On This
USA
175 Posts |
Posted - 01/01/2009 : 12:48:32 PM
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Thanks for the link.
I have found alot on info the 470, and the boat I was looking at in Washington had the larger cooler, the after market alternator, and the updated ignition. I think I guy knows what he is going, but one engine was already damaged, and from what I hear, the parts can be hard to find, and rather pricey when you do find them.
Talked to a guy that would accually give me trade in if I bought a couple 3.0's, but,as he told
me, the newer engines are all standard rotation, and that the port side 470 was counter rotation. That would mean at least one V drive would need to be changed.
So here is where your statement really runs true. Much cheaper to buy a boat with the power you want, even if they need overhauled.
I just can't seem to find anything we like with twins, that are not V8's.
The repower is not a problem for me, as I repower trucks and drill rigs as a living, but the cost would be a problem.
Just need to keep looking I guess.
Thanks
Bob
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28' Carver with twin 307
