Fuel Stretchers
How To Save Money With Every Fill-up—On The Water, On The Road
By Bruce W. SmithFuel prices
these days are bouncing around like a cork on the line of a
minnow about to be eaten by a wall hanger. But we all know the
prices are never going to drop back to the point where filling
up our tow vehicles and boats don’t have a sizeable impact on
our wallets.
Bass club members know that as much as anyone, especially
those in clubs that travel to fish waters outside of their
immediate area. A weekend club event like that can cost $300 in
fuel for the truck and boat.
Whether fishing locally or not, everyone in the club is
trying to figure out ways to stretch fuel mileage. A few are
looking at buying magic fuel-saving devices like those miracle
fish catching lures advertised on TV. Forget it. During my
20-plus-years road testing trucks for magazines, I’ve had the
opportunity to evaluate a lot of the miracle fuel economy
improvers in hopes one held some grain of truth to the claims.
None work.
That’s also the consensus of both the Federal Trade
Commission (FTC) and the Environmental Protection Agency (EPA),
the latter of which has evaluated or lab-tested more than 100
alleged gas-saving devices and has not found “any product that
significantly improves gas mileage.” (For a more information on
the validity of fuel-saving devices, go to:
www.ftc.gov/bcp/edu/pubs/consumer/autos/aut10.shtm )
What I have found is bettering fuel economy is like being
successful at bass fishing: it’s the person controlling the rod
that makes the difference, not the lure. If you want to maximize
your tow vehicle and boat’s fuel mileage numbers, be smart.
Driving Style
Your driving style plays the biggest factor in fuel economy both
on land and on the water. Think about it: Nearly half the energy
needed to power your tow vehicle goes to acceleration.
Heavy-footed starts waste a lot of fuel. Drive like you have
a hair-trigger under your right foot and anticipate traffic
conditions to avoid unnecessary hard braking or constantly
getting on and off the throttle. Drive smoothly and it’s easy to
improve your vehicle’s fuel economy by 10-15 percent. Similar
fuel economy results will be seen in your boat by keeping the
same driving thoughts in mind.
The same is true related to how fast you drive. I’m not a
follower. I am one of those bass boaters who likes running in
the fast lane—or at least I did until the price of gas at my
local gas station rolled past $3 per gallon for diesel. My
driving tune has changed. Now I’ve found myself driving a lot
like the patrons of Florida retirement homes.
Driving slower is not an easy transition. But I’ve seen the
reward at every fill-up, which is not surprising. According to
my auto manufacturing engineering friends who spend most of
their days in wind tunnels, more than half a pickup or SUV
engine’s power is used to overcome aerodynamic drag. This really
comes into play at speeds above 50mph. Drive 70mph-up and you’ll
see your truck’s fuel economy drop like an anchor.
Fuel economy changes are magnified when a boat is in tow.
Don’t be surprised to see your tow vehicle’s fuel economy
improve by 2-3mpg by reducing cruising speed from 70mph to
60mph. In other words you can save about $5 per fill-up, or
hundreds of dollars a year, just by slowing down a few
miles-per-hour.
At The Helm
The same holds true in your boat. If you really want to eek more
miles out of the tank, back off the throttle.
All boats have a sweet spot where fuel economy is maximized.
It’s typically 250-500rpm above the point the boat breaks off on
plane—or between 3000rpm-3500rpm for fiberglass bass boats. So
if you cruise between 3500-4000rpm, you’re maximizing fuel.
The reason a bass boat’s fuel economy peaks in that range is
actually quite simple: At the moment in time where the hull is
planning on top of the water instead of plowing through the
water, the engine is doing the least amount of work in relation
to the speed the boat is moving.
To further enhance fuel economy at that speed—or any speed
for that matter—it is vital the engine be trimmed so that it is
running parallel to the water’s surface. This takes a good feel
to find the trim point where the boat is running freest at any
given rpm.
If the engine is over-trimmed the boat will usually start
porpoising (the bow bouncing) or create too much wind drag; too
little trim and the bow will tend to plow through the water
and/or steer a little heavy. Either of those trim positions, or
hull attitude, will deal fuel economy a hard hit.
Tailgate Up
Wind drag also applies to your tow vehicle. If you want to
improve your tow vehicle’s fuel economy, keep that tailgate
closed. Argue with me as you may. But the facts are indisputable
that opening or removing the tailgate actually decreases fuel
economy at speeds above 55mph. (The position of the tailgate has
insignificant effect in city driving.)
"Our wind tunnel data falls in line with industry conclusions
- that the tailgate down configuration is significantly higher
in drag than the tailgate up (around 2-3%),” says Mark Gleason,
Supervisor / Aerodynamics at the Chrysler Proving Grounds.
“Although it seems counter intuitive, having the tailgate up
acts like a deck spoiler on the trunklid of a sports car; the
tailgate actually raises the pressures on the rearward facing
surfaces of the pickup cab and the forward surface of the bed,
thereby lowering the drag of the vehicle by 2- to 3 percent.”
As odd as it sounds, vehicle designers all say the tailgate
left in the up, or closed position, actually creates a large
bubble of air in the bed that aero engineers call a “separated
bubble” or “Locked Vortex Flow.” This invisible bubble of air
trapped inside the open bed box actually helps make the pickup
more aerodynamic—much like an invisible tonneau cover over the
bed box.
Tonneau Covers
Speaking of beds, the most effective device you buy for a pickup
to improve fuel economy is a tonneau cover. Hard or soft, it
doesn’t matter. Either betters fuel economy.
Last year the Specialty Equipment Market Association (SEMA)
released an in-depth study (www.trucktestdigest.com/PDFfiles/SEMATonneauStudy2007.pdf)where
they took a new Ford F-150, Dodge Ram and Chevy Silverado and
tested them with and without tonneau covers in a wind tunnel
used by a number of the NASCAR teams.
The AeroDyne Wind Tunnel testing results of that
sophisticated study showed a tonneau cover reduces drag by an
average of about six-percent—or the equivalent to improving fuel
economy about ½-mpg at speeds over 60mph.
Tire Pressure
Another area we as a truck-owning, boat-towing group tend to
overlook way too often: tire inflation pressures. The irony is
we are concerned more than ever about improving fuel economy,
yet an alarming number of us are driving around in vehicles and
towing trailers that have one or more tires dangerously
under-inflated.
Recent National Highway Transportation Safety Administration
(NHTSA) studies have found 40-percent of light-trucks and
27-percent of cars were driving around with at least one tire
that is under-inflated by 8psi or more of the recommended tire
pressure indicated on the vehicle’s door placard. It’s scary to
think how many trailer tires are also under-inflated.
Under-inflated tires give fuel economy a big hit;
under-inflated tires greatly increase rolling resistance. You
can literally be wasting a couple gallons of gas per tank by
driving around in a pickup or SUV with under-inflated tires and
towing a trailer with low tire pressures.
By the way, over-inflation doesn’t improve fuel economy. But
it does increase the chances of hydroplaning and overall poor
vehicle ride and handling while accelerating tire wear. So keep
truck and trailer tires inflated to the pressures recommended by
the vehicle and trailer manufacturer. No more. No less.
Weight Issues
If you are really serious about keeping your fuel costs
minimized, don’t be adding bigger, more aggressive tires or
lifting the vehicle. Now, I love lifted trucks. But I also know
how much lift kits and big tires hurt fuel economy.
When a lift kit and wider, taller tires are added, the truck’s
frontal area is now much larger, trapping more wind. More wind
resistance, less fuel economy. Even a moderate four-inch lift
can carve a couple miles-per-gallon off your factory fuel
numbers at highway speeds.
Weight also hurts fuel-economy—for both tow vehicle and boat.
Unload those old batteries, cinder blocks, sheets of plywood,
and seldom-used tool boxes from your truck before heading out on
a fishing trip. Carrying around an extra 100 pounds of
unnecessary stuff in your boat is the same as hauling around
another passenger. Think light. Think right.
Another fuel-saving factor in a boat is keeping weight away
from the bow and located more around the cockpit/helm area.
Weight upfront means you have to over-trim the engine to lift
the bow, which, as noted earlier, is not good for optimizing
fuel economy. Keep heavy items in the rear lockers, light stuff
up front.
Engine/Exhaust Upgrades
Cat-back exhaust systems and cold-air intakes are the fuel
economy lure-of-the-month for a lot of club members. Such
upgrades do, indeed, improve power and general performance. But
the cost invested in such performance parts will never be
recouped in fuel savings alone.
The same holds true for diesel power modules; they are
phenomenal in adding towing power, but the fuel economy gains
the manufacturer’s claim may not be realized unless you drive
with an egg under your right foot. Like I said earlier, fuel
economy is more dependent on the driver than the product.
What I’ve told you is common sense. Which method or methods
you take all depends on how serious you are about improving your
tow vehicle and boat’s fuel economy and reducing the cost of
going bass fishing.
Some of my fellow club members might think I’m driving like
an old lady as they follow me to the lake. But then I’m the one
who always has the lowest fuel bill at the pump and an extra
$600 to spend on some new electronics, fishing gear, or prop at
the end of the year.
Boat Setup
Speaking of props, here’s another little fuel economy tip on the
boat side of the equation: run a stainless steel prop instead of
an aluminum model. Aluminum props are usually 5- to 10-percent
slower than the equivalent stainless prop because aluminum
flexes a lot more as the blades travel through the water. Less
efficiency means less fuel economy.
Using the wrong pitch prop for your particular boat/outboard
setup, or running a prop that has dings in the leading edges of
the blades, will ding fuel economy. Prop blade type is also a
factor; the more blades and bigger diameter the prop, the more
drag in the water if the setup doesn’t give your boat the right
lift.
Generally three-blade props are more efficient than
four-blades, which are more efficient than five-blade models.
The difference in boat performance and fuel economy might not
warrant spending $500 buying a three-blade to replace a
perfectly good four-blade, but if someone in the club is willing
to make a sweet deal—and your boat runs freer with the new
prop—do it.
FUEL-FRIENDLY FISHING TIPS Yamaha’s fishing pros know how to stretch fuel when they have to
and shared these cool tips for Bass Club Digest readers:
- Plan Smart: Never leave the dock without a plan based on the
information you’ve gathered. Plan out the places you want to try
in logical order to reduce running time and eliminate
backtracking to reduce fuel use.
- Adjust Your Fishing Habits: Not all fishing requires long runs
to the fishing grounds and a constantly running engine. If
run-and-gun is how you fish now, try switching over to drift
fishing or anchoring up on structure areas to bottom fish. Use
the electric trolling motor more. Changing the way you fish and
the species you fish for can keep you fishing longer for less.
- Fuel-Efficient Engines: Today’s modern four-stroke and high
pressure direct injection two-stroke outboard motors are the
most fuel efficient marine engines ever made. The typical fuel
savings over an old carbureted engine can be 25 to 40 percent.
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