Gas engines can be almost as safe as diesel if they are properly
maintained and operated. In my opinion that should not be the deciding
factor. The real issues are power, torque, range and economy. There
is a break point somewhere around 12 to 15,000 pounds of boat weight
where gas engines will not develop sufficient power for decent,
economical performance.

The HP numbers are deceptive, but the bottom line is that you can not
run a gas engine at more than about 50% of its rated horsepower without
seriously compromising durability/longevity. Diesels however routinely
cruise at 80 to 85% of maximum horsepower and use about half as much
fuel.

I found this out the hard way with my previous boat which was powered
with twin 350 hp gas engines and weighed about 22,000 pounds.
Performance and range were never at a level that I was happy with, and
fuel consumption was 35 to 40 gph. With 350 hp diesels, cruising speed
would have been in the mid to high 20s, fuel consumption around 25 gph,
and cruising range almost doubled.

wrote in message
oups.com...
Gas engines can be almost as safe as diesel if they are properly
maintained and operated. In my opinion that should not be the deciding
factor. The real issues are power, torque, range and economy. There
is a break point somewhere around 12 to 15,000 pounds of boat weight
where gas engines will not develop sufficient power for decent,
economical performance.

The HP numbers are deceptive, but the bottom line is that you can not
run a gas engine at more than about 50% of its rated horsepower without
seriously compromising durability/longevity. Diesels however routinely
cruise at 80 to 85% of maximum horsepower and use about half as much
fuel.

Hmmm.....the 6400 lb displacement, 27' cruiser I'm considering is powered by
a single 250 hp gas engine. Would you say that it is underpowered?

-Greg

"Dene" dene@(nospam) ipns.com wrote in news:2s2dnXULnOa_4M3eRVn-
:

Would you say that it is underpowered?

It's overpowered at $4/gallon!....(c;

--
Larry

Hmmm.....the 6400 lb displacement, 27' cruiser I'm considering is powered by
a single 250 hp gas engine. Would you say that it is underpowered?

It depends what kind of performance and engine durability you are
expecting. I have a 5000 lb I/O cuddy with a 5.7L 260 hp engine. At
3400 RPM it cruises at 24 kts in flat water which I regard as OK but
nothing exceptional. It burns 13 gph at that speed and has been
reasonably reliable.

The point of my previous post was that there is an upper weight limit
where it becomes impossible to get adequate performance from gas
engines, even with fuel injected big blocks. At 6400 lbs you are well
under that limit but a bit underpowered unless you go to twins or
bigger engine. Twins become difficult to maintain in a boat that size
because of close engine spacing.

wrote in
oups.com:

twin 350 hp gas engines

Can someone explain to me why many people who buy a boat are always in such
a damned hurry to "get there"? I'm always frustrated by people we sail
with, mostly guests, that just go schitzo when the wind dies, the sails go
limp and we just SIT THERE, 90 miles offshore of anything.

Wasn't that why we got on the boat in the first place?.....to get away???
Being becalmed is so peaceful! Gives you an opportunity to eat a decent
meal, take a shower without being beaten around and just SLEEP IT OFF.

I hate it when they start deciding to crank the diesel and head
"there"....how awful. In a hurry? Take a JET!

I think how awful it is every time I see some nice trawler in the ICW
plowing up a big bow wave it shouldn't have as its owner has his twin 300hp
diesels just cranked up hard. Fast Trawler? Isn't that an oxymoron??

--
Larry
Oh, oh, the wind died! Quick, someone open that hatch and get out the
barbie before it freshens back up! THAT'S LIVIN'!

Can someone explain to me why many people who buy a boat are always in such
a damned hurry to "get there"?
......
I think how awful it is every time I see some nice trawler in the ICW
plowing up a big bow wave it shouldn't have as its owner has his twin 300hp
diesels just cranked up hard. Fast Trawler? Isn't that an oxymoron??

Larry, aren't you the guy who used to enjoy zipping around Charleston
Harbor in your 50 mph jet boat? Fun, right?

And sometimes you just need to get somewhere...

wrote:
Gas engines can be almost as safe as diesel if they are properly
maintained and operated.

That's true. But there is still a big difference, in that the diesels
are safe with no special action by the operator, while gas engines are
'almost as safe' (I like that phrase, thanks) only if proper procedures
are followed. The operator must take certain actions without exception.


... In my opinion that should not be the deciding
factor. The real issues are power, torque, range and economy. There
is a break point somewhere around 12 to 15,000 pounds of boat weight
where gas engines will not develop sufficient power for decent,
economical performance.

It may be a power/weight range, some big muscle boats seem to do OK with
gas... not may area of expertise.

But I wanted to add my 2 pence by saying that resale value is also a big
difference between the two, as is reliability... diesels are better in
both categories, of course...

Fair Skies
Doug King