Just got back from a 45 mile cruise up the gorge, most of which was at
cruising speed, 28 mph, 3200 rpm's. Used 18 gals. which translates into
2.5 miles/gal. Does that seem right for a 25' V hull with a 5.7 liter,
Alpha Drive? (I thought it would be 1.7 or so).

-Greg

On Mon, 23 Jan 2006 14:11:32 -0800, "Dene" wrote:

Used 18 gals. which translates into
2.5 miles/gal. Does that seem right for a 25' V hull with a 5.7 liter,
Alpha Drive? (I thought it would be 1.7 or so).

Sounds unusually good for a 5.7 on a 25 footer. I have one on a 24
and average about 2 mpg cruising at 3400.

Dene wrote:
Just got back from a 45 mile cruise up the gorge, most of which was at
cruising speed, 28 mph, 3200 rpm's. Used 18 gals. which translates into
2.5 miles/gal. Does that seem right for a 25' V hull with a 5.7 liter,
Alpha Drive? (I thought it would be 1.7 or so).

-Greg

That sounds great. I only get about 4nmpg, and that's at less than 1/3
of the speed you make...(but in a slightly larger boat).

sounds pretty good to me, especially for a boat that size

of course, if you backed it down to about 3000 rpm the speed wouldn't
be much different, and the savings in fuel can be a better edge even
yet.

I've run my little Chris Craft with a 4 banger alpha 1 at 3000 and it
does rather well. at 3500 the fuel consumption goes up with little
speed change, and 4000 rpm the fuel really drops and doesn't gain
hardly much speed over the 3500.

I suppose you might say that the percentage of speed vs. consumption
really drops out of your favor the higher rpm you go.

"Tim" wrote in message
oups.com...
of course, if you backed it down to about 3000 rpm the speed wouldn't
be much different, and the savings in fuel can be a better edge even
yet.

I've run my little Chris Craft with a 4 banger alpha 1 at 3000 and it
does rather well. at 3500 the fuel consumption goes up with little
speed change, and 4000 rpm the fuel really drops and doesn't gain
hardly much speed over the 3500.

I suppose you might say that the percentage of speed vs. consumption
really drops out of your favor the higher rpm you go.

3000 rpms puts me below cruising speed and I start to de-plane. That's one
thing that irritates me about a mono-hull compared to the cats I'm drooling
over. With my monohull boat, I can only go 3 speeds, slow (which feels like
a one armed swimmer), cruising speed, or faster. The cat I will have
someday should allow me to go 15 mph or 30 mph without significant
differences in the ride or handling.

-Greg

On Tue, 24 Jan 2006 15:03:15 -0800, "Dene" wrote:

3000 rpms puts me below cruising speed and I start to de-plane.

You may be able to fix that to some extent by using trim tabs to bring
the stern up and the bow down.

"Wayne.B" wrote in message
...
On Tue, 24 Jan 2006 15:03:15 -0800, "Dene" wrote:

3000 rpms puts me below cruising speed and I start to de-plane.

You may be able to fix that to some extent by using trim tabs to bring
the stern up and the bow down.

I have those and it does help. But....I like going 28 mph. Probably stems
from owning a 18 ft. runabout for 20 years.

-Greg

On Wed, 25 Jan 2006 13:44:40 -0800, "Dene" wrote:

I like going 28 mph.

That's a different problem. :-)

Dene wrote:

"Wayne.B" wrote in message
...

On Tue, 24 Jan 2006 15:03:15 -0800, "Dene" wrote:


3000 rpms puts me below cruising speed and I start to de-plane.

You may be able to fix that to some extent by using trim tabs to bring
the stern up and the bow down.


I have those and it does help. But....I like going 28 mph. Probably stems
from owning a 18 ft. runabout for 20 years.

-Greg



I have trim tabs on my 21ft cuddy, Yes you can keep it on plane going
very slow. the boat can go so slow that the speed stops registering.
Also makes a big whole in the water right behind the boat. The cuddy has
high side and they help with leveling the boat out in a big cross wind
as well.

Interesting enought 28 mph is where I like to run :-) It's a nice easy
speed and one can enjoy the sights.

Capt Jack R..