Fuel saving tips
 

I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

Fuel saving tips
 

And use that trim control for optimum speed/rpm combo.

"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

Fuel saving tips
 

It's easy, don't drive your SUV 80mph to get to the boat!

"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

Fuel saving tips
 

Coast when your going downhill :)~

Fuel saving tips
 

Bowgus wrote:

And use that trim control for optimum speed/rpm combo.


Aha! I would have overlooked that, thanks.
Your point has been blatantly hijacked and included in my rough draft. :-)



Don't be so Fuelish!


Holy hydrocarbons! All the dead dinosaurs currently being pumped at the local
fuel docks must surely have been the thoroughbreds of their day. As the summer
cruise season gets underway, gas and diesel prices are high, yi, yi, yi, er
than we've ever seen, (if inflation isn't factored into the equation).

What's a boater to do? Fortunately, we have some realistic choices that go well
beyond staying ashore and moping. Without suffering major expense or
inconvenience, almost everyone can make some simple adjustments and systems
checks that will reduce fuel costs this summer. In some cases, the savings will
prove significant.

Boaters should always be careful to maintain a nice, clean bottom. Lack of
attention can result in an embarrassingly "hairy" surface, further plagued by
unsightly, crusty organisms clinging to formerly smooth, unblemished surfaces.
It it's been a while since the last careful examination, it may be time to take
your bottom (and the boat it's attached to, of course) to the nearest boatyard
for inspection, correction, and preventive maintenance. The "beard" of seaweed
and the hitch-hiking barnacles can retard a boat's progress through the water
and decrease fuel efficiency as a result.

The energy developed by burning fuel aboard a powerboat is ultimately
transmitted to the water by the prop. Boats fitted with a propeller pitched too
aggressively or too large in diameter will be "lugging", and the over-propped
condition will keep the boat from ever reaching the manufacturer's rpm rating.
If the engine is running at a wide open or well open throttle and not achieving
its potential speed, some fuel is being wasted. If a boat is equipped with an
undersized propeller, it will easily reach or exceed its full rpm rating but
will not convert the engine speed into boat speed with adequate efficiency.
Boaters who have been "putting up with" improperly sized propellers may find
this a compelling year to make the correction.

Engines that are running efficiently burn less fuel. Is it time for fresh
sparkplugs or other ignition components on a gas engine? Are the injectors
overdue for service on a diesel?
These and similar preventive maintenance chores can't be postponed forever, and
doing the work prior to setting off on an annual vacation cruise will allow the
immediate fuel savings to help defray a portion of the cost.

Prepare to lighten ship! The smaller the boat, the greater the difference an
extra thousand pounds of "stuff" will make when operating. Basic safety gear
and spares should remain aboard, of course, but a spike in the cost of fuel is
as good an excuse as any to go through lockers, lazarettes, etc, and review the
inventory. Most of us will be surprised at the amount of seldom or never used,
(sometimes even completely forgotten), stores, supplies, tools, and personal
belongings stowed aboard.

Don't boat "upstream" when avoidable. In most of our local tidal waters, there
are only the briefest periods when the current is truly slack. Prudent planning
and timing of a cruise can make a significant difference in net speed over
ground, (and therefore actual fuel efficiency). Displacement boats realize more
dramatic benefit from the advantageous use of currents than planing boats. An
eight-knot boat bucking a three-knot current will achieve a net five-knots,
while the same vessel running with a three-knot current will be logging
eleven-knots SOG, (more than twice the speed with the same fuel burn).

And last but far from least, slow down! (But perhaps not too much.) The two
most efficient speeds for typical planing hulls are pure idle, and the speed at
which the boat rises over the bow wave to assume a planing attitude. Backing
off the throttle to where a boat falls off plane will reduce the gph fuel
consumption, but can easily reduce the speed so disproportionately that the
nmpg is actually less at the lower speed. Once a vessel has achieved planing
status, additional throttle will often burn significantly more fuel to achieve
only relatively modest increases of speed.

Judicious use of trim tabs, when so equipped, can often help a boater achieve
or maintain plane at a slower engine rpm.

Even if it isn't practical to clean the bottom, tune or service the engine,
correct an improperly specified propeller, remove excess weight for the boat,
or plan cruises to take advantage of favorable currents, many of us can realize
significant savings merely by reviewing our customary cruising speeds.

Cruising a bit slower may sound almost heretical to many boaters, but let's
examine a real life example of the type of efficiencies that can be realized.
Douglas Silvestri, of Port Orchard, Washington, kept careful fuel consumption
records on his 36-foot Uniflite equipped with twin 460 gas engines and Flo-Scan
fuel meters. Silvestri recently traded for a different boat, but he kept his
old records.

"At 2700 rpm, I would make 14.1 kts in the Uniflite. My combined fuel burn at
that speed, for both engines, was 14.2 gallons per hour, or almost exactly
1nmpg."

"By slowing down to 2000 rpm, my speed dropped to 10 kts, but my fuel burn was
reduced to 8.2 gph, according to the Flo-Scans."

Doug's fuel efficiency, on a nmpg basis, was roughly 25% better at 2000 rpm and
10 kts than it was at 2700 rpm and 14. Doug actually got reasonably decent fuel
economy from the twin 460's in his Uniflite, many similar and larger boats use
significantly more fuel per hour and a decrease in speed could result in even
more dramatic savings.

Here in the Northwest, many boaters would hardly notice the difference in
Doug's two speeds, but most would appreciate the difference in fuel costs. A
250 nautical mile summer vacation cruise would require 25 cruising hours at
10-knots, or just under 18 cruising hours at 14.1. If the 250 nautical miles
were logged over ten days, the average running time per day would only be 42
minutes longer at the slower speed. Eighteen hours at 14 gph would burn 252
gallons at the higher speed, while 25 hours at 8.2 gph would burn only 205. By
spending an extra 42 minutes per day on the water, (and isn't that what boating
is supposed to be about?) Silvestri's old boat would use 47 fewer gallons on
that typical, but hypothetical, NW vacation cruise. At $2.80 a gallon, that
47-gallon savings would reduce the fuel costs by $131. One-hundred-thirty -one
dollars isn't a lot of money in the grand scheme of boating expenses, but its
an amount that almost anybody would stoop down to pick up if it were laying
unclaimed on the dock . For many of us, that much or considerably more almost
certainly is.

Fuel saving tips
 

Uhhh.. don't buy a jet outboard.


--
{{ MudFish (Co30){('
www.Co30.com
"Careful with that Axe Eugene."

"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

Fuel saving tips
 

Talking about fuel savings in the same sentence as pleasure boating
is a bit like the dieter that orders a cheese-burger, fries, apple-pie
and DIET coke, but...

I see someone mentioned trim.for "optimum speed/rpm combo". Maybe
this also falls under the same heading, but shouldn't a boat be trimmed
or gear moved so that is sets evenly? In other words so it isn't listing
to one side or the other.

I think a fuel-flow meter might help. Of course, installing one
might be more of a hassel or expense than it's worth. But having that
direct & immediate feedback has to help one to find the "sweet spots"
and to also keep their mind on that task.

This might be too obvious for your column, and isn't really "fuel" saving
but money saving, but if it's a trailerer boat, filling up at a gas station
and not a marina will save money.

What about ideling? At what point does shuttnig off the engine & restarting
it use more fuel than ideling? Of course, it's different for different
engines.

And before someone else posts it.....Buy a sail boat.





"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

Fuel saving tips
 

Gary Warner wrote:

Talking about fuel savings in the same sentence as pleasure boating
is a bit like the dieter that orders a cheese-burger, fries, apple-pie
and DIET coke, but...

I see someone mentioned trim.for "optimum speed/rpm combo". Maybe
this also falls under the same heading, but shouldn't a boat be trimmed
or gear moved so that is sets evenly? In other words so it isn't listing
to one side or the other.

I think a fuel-flow meter might help. Of course, installing one
might be more of a hassel or expense than it's worth. But having that
direct & immediate feedback has to help one to find the "sweet spots"
and to also keep their mind on that task.


Installing a Standard Horizon fuel flow meter was simple, although to do
it neatly took some time. I know, because I watched the dealer's boat
rigger do it!

Basically, it required one snip of the fuel line between the external
filter and the engine, the insertion of a small flow/sender unit in the
line, the clamping together of the fuel line with the sender it it, the
stringing of a wire to the dash, the drilling of a holw in the dash for
the gauge, and two minutes of panel wiring.

Fuel saving tips
 

"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

7. Leave the wife at home (as unnecessary gear) to reduce weight grin
8. Move people around in the boat to balance

Fuel saving tips
 

Do a tune up once in a while.

"Jeff Rigby" wrote in message
...

"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing
hull).
6. Plan cruise consistent with tidal currents when applicable and
possible

Any other good'ns?

7. Leave the wife at home (as unnecessary gear) to reduce weight grin
8. Move people around in the boat to balance

Fuel saving tips
 

a. Don't take any fat chicks out in the boat with you
b. Since water is heavier than alcohol, take only beer to drink
c. When launching or recovering, just tie up boat directly to the ramp
dock-don't idle around to another out of the way location
d. Buy a boat with a Force L Drive so you will usually be under tow and not
running your engine
e. Don't swerve to avoid the lake lice
f. Insist women wear bikinis instead of one piece swim suits to save weight


"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

Fuel saving tips
 

a. Don't take any fat chicks out in the boat with you
f. Insist women wear bikinis instead of one piece swim suits to save
weight"

As long as a and f are both rigorously enforced, I'm with ya Bomar! ;-)

- Michael

Fuel saving tips
 

"Harry Krause" wrote


Installing a Standard Horizon fuel flow meter was simple, although to do
it neatly took some time. I know, because I watched the dealer's boat
rigger do it!

Basically, it required one snip of the fuel line between the external
filter and the engine, the insertion of a small flow/sender unit in the
line, the clamping together of the fuel line with the sender it it, the
stringing of a wire to the dash, the drilling of a holw in the dash for
the gauge, and two minutes of panel wiring.

I actually installed a SH fuel flow meter - and it's as easy as he said.
Splice the sender into the fuel line where specified, run cable to gauge at
dash, wire gauge to switched current and ground.

Used FF meter for first time this weekend and really liked it. The SH meter
is digital and has a fuel used as well as a fuel remaining feature (you
program in the beginning fuel amount and it will tell you how much is
remaining as well as an alarm feature). Haven't calibrated it yet, but it
appears to be within 5% or less right out of the box as far as fuel used. I
like it and it has definitely given me a better idea of where the sweet spot
is. Really liked the fuel used feature since I don't have dash gauges for
fuel tanks (which often arent' accurate anyway).

Cam

Fuel saving tips
 

"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

When going upstream, especially in swift rivers, avoid fastest current when
possible. Of course, this is within safe boating practices including
keeping on the correct side of stream, in deep enough channel, and other
rules of road. But there's quite a bit of runnig that can be done in
relatively weak current like inside of bends and other natural slacker
areas.

Opposite principle when going down stream -try to maximize your time in the
stronger current.

Fuel saving tips
 

"Gould 0738" wrote in message
...
I'm writing a "filler" with some fuel saving tips.

With a boat as economical as mine, I don't dare save too much fuel or it
will
begin increasing in volume and pouring through the vents. :-)
As a result, I haven't made a real thorough first hand study of fuel
saving
techniques.

So , I'm shamelessly trolling for ideas to add to the few I have already
thought to include.

So far I've got:

1. Make sure bottom is clean
2. Make sure boat is correctly propped
3. Make sure engine has been tuned up and serviced
4. Take excess gear off of boat to reduce weight
5. Reduce cruising speed, (without falling from plane if a planing hull).
6. Plan cruise consistent with tidal currents when applicable and possible

Any other good'ns?

7. Spend more time making political posts on rec.boats and less time
actually out boating...you know, like basskisser.
8. Balance the weight so trim tabs don't need to be used as much...which
creates excess drag
9. Use proper trim on outboards and outdrives.

Fuel saving tips
 

actually, it's pretty simple, go slower

Fuel saving tips
 

"Florida Keyz" wrote in message
...
actually, it's pretty simple, go slower

Slower than what? Planing hulls going slower than planing speed are much
less efficient.

Fuel saving tips
 

Slower than what? Planing hulls going slower than planing speed are much
less efficient.

Actually, i am not so sure about that, I have a 44 marine trader with twin 270
hp lemans, I cruise at 9 mph (knots are for sailors with lots of time on their
hands) and average 1mpg., as do most of the reports I see from the great loop.
Whats better??

Fuel saving tips
 

"Florida Keyz" wrote in message
...
Slower than what? Planing hulls going slower than planing speed are much
less efficient.

Actually, i am not so sure about that, I have a 44 marine trader with twin
270
hp lemans, I cruise at 9 mph (knots are for sailors with lots of time on
their
hands) and average 1mpg., as do most of the reports I see from the great
loop.
Whats better??

In my quick and dirty testing of my new flow meter this weekend - about 50
miles total in a variety of lake and river conditions - the sweet spot that
maximizes miles per gallon definitely is at planing speed. I'm not sure
exactly where yet, but it didn't even appear to be at slowest planing speed,
but more testing is needed!

The bad news is that I'm not going to get more than 2 mpg and often a little
less, it seems.

Cam

Fuel saving tips
 

actually, it's pretty simple, go slower


NOYB wrote:
Slower than what? Planing hulls going slower than planing speed are much
less efficient.

Nope. This is a common motorboater's misconception.

If you doubt it, look at the fuel test results commonly printed in
magazines. You will see immediately that faster=greater fuel consumption
per distance, except for boats that are very far up the power/weight
curve (ie muscle boats) and they get such poor fuel economy it doesn't
matter.

Fair Skies
Doug King

Fuel saving tips
 

Slower than what? Planing hulls going slower than planing speed are much
less efficient.

Actually, i am not so sure about that, I have a 44 marine trader with twin
270
hp lemans, I cruise at 9 mph (knots are for sailors with lots of time on
their

Your 44 Marine Trader is not a planing hull.

It's a semi-displacement trawler.

At what rpm do you make 8 kt? (about 9 mph)

Experiment with slowing down to 7 kt, and you might realize a 25-30 percent
increase in fuel economy. I have experienced that kind of results in the past,
in a smaller hull with similar characteristics.

Caveat: Running a diesel engine too slowly for an extended period of time is
not generally recommended. As you know, they thrive on exercise.

Fuel saving tips
 

Make sure if running twins that they are in sync.

Find your boats sweet spot. On most planeing hulls idle speed is probably most
efficient but if I wanted to go that slow I would have purchased a sailboat.

On my boat for example the "sweet spot" is 3100 RPM with the drives trimmed
slightly up. This gets me, depending on conditions anywhere from 28 to 30 MPH
and a fuel burn of just under 11 GPH. Of course wind, load and currents can
affect this but these are my averages over 5 seasons of usage.

BTW, gasoline at my marina is $2.339 for 89 octane, on the street anywhere from
$1.999 to $2.299 for 87 octane. Not to shabby. Other marinas are charging from
$2.45 to $2.75 per gallon. My marina and the other marina in my harbor have
always been lower than the norm for some reason. Maybe that is why both are
full.

Fuel saving tips
 

I get 9 mph at 14oo rpm.

Fuel saving tips
 

"Florida Keyz" wrote in message
...
Slower than what? Planing hulls going slower than planing speed are much
less efficient.

Actually, i am not so sure about that, I have a 44 marine trader

A Marine Trader is not a "planing hull".

Fuel saving tips
 

"DSK" wrote in message
...
actually, it's pretty simple, go slower


NOYB wrote:
Slower than what? Planing hulls going slower than planing speed are
much
less efficient.

Nope. This is a common motorboater's misconception.

If you doubt it, look at the fuel test results commonly printed in
magazines.

Just checked June 2004 Powerboat Reports, page 13

Boat/engine: Triumph 210 Chaos center console with single Honda 4-stroke
150hp

Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg

So in this example, the most efficient (best mpg) speed is when the boat is
on plane at 25 mph. In two-strokes, the difference would be even more
dramatic since two-strokes consume significantly more gas than 4-strokes
when travelling at trolling speed.

Fuel saving tips
 

Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg


TILT!

(occurs to me you kids don't fully appreciate that term).......

The performance curve seems out of whack.

The boat travels 6 mph at 1500 rpm.
Seems really slow, but let's use that.
It ought to do 6mph at a fast idle, one would think.

2500 rpm is only 9 mph? Still seems really, really, really slow, but let's use
that.

If 2500 rpm is propelling this vessel at 9mph, it stretches the imagination to
consider that adding 500 rpm will increase the speed by a factor of 2 1/2
times, or an additional 16mph.

Not saying it isn't so, just that it seems very unusual.

Sure the 2500 rpm isn't 19 mph, instead of
9?

Fuel saving tips
 

My experience with my 4 stroke merc 60 is it uses less than 1 GPH at "slow"
(AKA "manatee zone") speed. Since I always end up right back where I started
and I don't really have a mission at the other end of the ride, who cares how
fast I go getting there or how far "there" is ?

Fuel saving tips
 

"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg


TILT!

(occurs to me you kids don't fully appreciate that term).......

The performance curve seems out of whack.

The boat travels 6 mph at 1500 rpm.
Seems really slow, but let's use that.
It ought to do 6mph at a fast idle, one would think.

2500 rpm is only 9 mph? Still seems really, really, really slow, but
let's use
that.

If 2500 rpm is propelling this vessel at 9mph, it stretches the
imagination to
consider that adding 500 rpm will increase the speed by a factor of 2
1/2
times, or an additional 16mph.

Not saying it isn't so, just that it seems very unusual.

Sure the 2500 rpm isn't 19 mph, instead of
9?

Doesn't seem unusual to me at all. At around 2500 rpms is about where
mine drops off plane and essentiallly plows water.....much of the energy
produced by the engines is being used to push water out of the way, not move
the boat forward. At rpms around 1500, more energy is moving the boat
forward than pushing water,(less wake for example) and the same is true at
3000 with the hull on plane.

Fuel saving tips
 

"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg


TILT!

(occurs to me you kids don't fully appreciate that term).......

The performance curve seems out of whack.

The boat travels 6 mph at 1500 rpm.
Seems really slow, but let's use that.
It ought to do 6mph at a fast idle, one would think.

2500 rpm is only 9 mph? Still seems really, really, really slow, but let's
use
that.

If 2500 rpm is propelling this vessel at 9mph, it stretches the
imagination to
consider that adding 500 rpm will increase the speed by a factor of 2 1/2
times, or an additional 16mph.

Not saying it isn't so, just that it seems very unusual.

Sure the 2500 rpm isn't 19 mph, instead of
9?


I dunno, Gould. Those are the numbers in the article I cited. You could go
to Yamaha Motor's website and look at others, but I don't have time right
now. Check the "Performance Data" section. I'll check later if I get a
chance.

Fuel saving tips
 

Here's one for you:
http://www.yamaha-motor.com/products...triumph/bullet
in_otb_4StrokePerf_MidThrustJetPort_115hp_03-48-TPH-C.pdf

Best economy is at 1000RPM (4.3mph): 10.33mpg

At 1500rpm (5.7mph) : 6.7mpg

At 4000rpm (27.2mph): 7.22mpg

The Powerboats Report article doesn't list mpg below 1500rpm, where, for a
four-stroke, you get the best efficiency.
On two-strokes, it could be very different. I'll check later.



"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg


TILT!

(occurs to me you kids don't fully appreciate that term).......

The performance curve seems out of whack.

The boat travels 6 mph at 1500 rpm.
Seems really slow, but let's use that.
It ought to do 6mph at a fast idle, one would think.

2500 rpm is only 9 mph? Still seems really, really, really slow, but let's
use
that.

If 2500 rpm is propelling this vessel at 9mph, it stretches the
imagination to
consider that adding 500 rpm will increase the speed by a factor of 2 1/2
times, or an additional 16mph.

Not saying it isn't so, just that it seems very unusual.

Sure the 2500 rpm isn't 19 mph, instead of
9?

Fuel saving tips
 

Paul Fritz wrote:
Doesn't seem unusual to me at all. At around 2500 rpms is about where
mine drops off plane and essentiallly plows water.....much of the energy
produced by the engines is being used to push water out of the way, not move
the boat forward. At rpms around 1500, more energy is moving the boat
forward than pushing water,(less wake for example) and the same is true at
3000 with the hull on plane.

A bit of physics here... with the hull on plane, the energy required to
lift the boat is coming from the engine.

It's possible that gas mileage for light planing hulls has improved in
recent years. But the efficiency curve still isn't going to go backwards
to any significant degree, and adding any load to the boat is going to
make the curve steeper (ie higher penalty on mileage at higher speeds).

Motorboaters deny it to their dying breath, but it's like arguing
against gravity. Speed costs. Sorry to be the bearer of bad news.

Fair Skies
Doug King

Fuel saving tips
 

Gould,
Since you boat with a trawler I think you have forgotten what happens when a
planning hull is no longer planning but is "muscling" it's way through the
water. Most boats drop off of planning at 2200 rpm to 2800 rpm.
The numbers do look reasonable for a "planning hull".


"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg


TILT!

(occurs to me you kids don't fully appreciate that term).......

The performance curve seems out of whack.

The boat travels 6 mph at 1500 rpm.
Seems really slow, but let's use that.
It ought to do 6mph at a fast idle, one would think.

2500 rpm is only 9 mph? Still seems really, really, really slow, but let's
use
that.

If 2500 rpm is propelling this vessel at 9mph, it stretches the
imagination to
consider that adding 500 rpm will increase the speed by a factor of 2 1/2
times, or an additional 16mph.

Not saying it isn't so, just that it seems very unusual.

Sure the 2500 rpm isn't 19 mph, instead of
9?

Fuel saving tips
 

On Thu, 03 Jun 2004 15:03:10 GMT, "John Smith"
wrote:
Gould,
Since you boat with a trawler I think you have forgotten what happens when a
planning hull is no longer planning but is "muscling" it's way through the
water. Most boats drop off of planning at 2200 rpm to 2800 rpm.
The numbers do look reasonable for a "planning hull".


"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg

==================================================

The numbers are reasonable for a planing hull, problem is that they
didn't test at lower than 1500 RPM. At 1500 the boat is already
exceeding its hull speed by a considerable margin and leaving a big
wake. If they had tested at 1000 RPM the results would have been as
expected and shown the best fuel economy. No one wants to travel at
that speed with a planing hull of course, but that is where the best
economy is.

Fuel saving tips
 

Gould,
Since you boat with a trawler I think you have forgotten what happens when a
planning hull is no longer planning but is "muscling" it's way through the
water. Most boats drop off of planning at 2200 rpm to 2800 rpm.
The numbers do look reasonable for a "planning hull".

Once a month I do test runs on a wide variety of different boats. A number of
them are planing hulls. I cannot remember a boat where an increase of 500 rpm
would have brought the boat from 9mph to 25mph. As I said, I'm not in a
position to comment on that specific boat, but the numbers seem strange to me.

Once a boat is over the bow wake and on plane, (which should be occuring
somewhere in the low to mid teens speed wise), in most cases fuel consumption
goes up exponentially to obtain additional speed. It would be interesting to
view a speed/fuel chart for the boat NOYB is referring to.

A boat with the operating characteristics NOYB described would be frustrating
as hell. A difference of 500 RPM increases the speed by 2 1/2 times? Unless you
wanted to run (and the conditions permitted) 25mph, you'd have a dickens of a
time setting the throttle for a speed somewhere between 9mph and 25mph and
keeping the boat there. Everytime a mosquito landed on the throttle lever you'd
pick up or lose a couple of miles an hour. :-)

Fuel saving tips
 

Doesn't seem unusual to me at all. At around 2500 rpms is about where
mine drops off plane and essentiallly plows water....

Ok, let's say your boat drops off plane at 2500 RPM. (Are we talking OB motor?)

Let's say that just off plane in your boat is
9 mph.

At 2600 rpm we'll say you're back on plane at 10-11 mph. Adding 400 rpm to that
will bring you to 25 mph?

Something is fracturing my paradigm. Very light boats, outboard motors, or
something else I don't typically experience.

Fuel saving tips
 

Best economy is at 1000RPM (4.3mph): 10.33mpg

At 1500rpm (5.7mph) : 6.7mpg

At 4000rpm (27.2mph): 7.22mpg

Now that seems more reasonable.
A 2500 rpm increase taking the boat from
6 mph to 27 is more believable (to me) than a 500 rpm increase taking the boat
from 9mph to 25.

Fuel saving tips
 

"Gould 0738" wrote in message
...
Everytime a mosquito landed on the throttle lever you'd
pick up or lose a couple of miles an hour. :-)


Well it seems like the answer is to keep mosquitoes off the throttle lever.
: - )

Fuel saving tips
 

"Gould 0738" wrote in message
...
Doesn't seem unusual to me at all. At around 2500 rpms is about where
mine drops off plane and essentiallly plows water....

Ok, let's say your boat drops off plane at 2500 RPM. (Are we talking OB
motor?)

Let's say that just off plane in your boat is
9 mph.

At 2600 rpm we'll say you're back on plane at 10-11 mph.

My 17' Whaler can stay on plane at about 13mph. Very few v-bottom boats can
plane at that slow a speed...so I doubt the Triumph is back on plane at 2600
rpm and a speed of 10-11mph.

Adding 400 rpm to that
will bring you to 25 mph?

An engine needs to run at a higher RPM to initially jump onto plane than it
does to maintain planing speed. However, I think you're incorrectly
assuming that the boat started planing at 10-11mph.




Something is fracturing my paradigm. Very light boats, outboard motors, or
something else I don't typically experience.


Light boats, yes. Outboards? Probably no different from an
I/O...definitely different from an inboard.

I think what you're missing is that there is less drag on a boat when it is
running fast and high out of the water, then when it's running at a speed
off-plane or just on-plane.

It's the same reason a boat runs faster with the engine trimmed out. Less
drag.

Fuel saving tips
 

"Gould 0738" wrote in message
...
Best economy is at 1000RPM (4.3mph): 10.33mpg

At 1500rpm (5.7mph) : 6.7mpg

At 4000rpm (27.2mph): 7.22mpg

Now that seems more reasonable.
A 2500 rpm increase taking the boat from
6 mph to 27 is more believable (to me) than a 500 rpm increase taking the
boat
from 9mph to 25.

The reason the first one didn't make sense to you is that you're forgetting
that the point of maximum drag is at the speed you're running right before
you jump on plane. At 9 mph, that boat is pushing tons of water. At 25
mph, that boat is displacing much less water.

Fuel saving tips
 

"Wayne.B" wrote in message
...
On Thu, 03 Jun 2004 15:03:10 GMT, "John Smith"
wrote:
Gould,
Since you boat with a trawler I think you have forgotten what happens
when a
planning hull is no longer planning but is "muscling" it's way through
the
water. Most boats drop off of planning at 2200 rpm to 2800 rpm.
The numbers do look reasonable for a "planning hull".


"Gould 0738" wrote in message
...
Mileage at 1500 rpm (6mph): approximately 6.2mpg
Mileage at 2500 rpm(9mph): approximately 3.5 mpg
Mileage at 3000 rpm(25mph): approximately 6.5mpg

==================================================

The numbers are reasonable for a planing hull, problem is that they
didn't test at lower than 1500 RPM. At 1500 the boat is already
exceeding its hull speed by a considerable margin and leaving a big
wake. If they had tested at 1000 RPM the results would have been as
expected and shown the best fuel economy. No one wants to travel at
that speed with a planing hull of course, but that is where the best
economy is.


Exactly!