GOING THE EXTRA MILE
Tips for bettering on-water fuel economy and saving dollars
By Bruce W. Smith
We were a good 10 miles from Lake Meade’s main
boat ramp, throttle on the stop to make a big club tournament
weigh-in when my partner looked over at me from the helm with
this worried look on his face and said, “Hope we make it back.
The fuel gauge is sitting on the peg.”
Five minutes later we were dead in the water.
“John” frantically dug out a 2 1/2-gallon gas
can secreted down in the bilge and drained it into the boat’s
empty tank, all the while praying we’d make weigh-in, lest I do
him great bodily harm. We made it, but lost valuable tournament
points for being late.
I’m sure we aren’t the only bass anglers to
face the ran-out-of-gas dilemma.
Like all smart boaters, my buddy had dutifully
filled his 20-foot Javelin’s 50-gallon fuel tank before setting
out on a run that would take us some 80 miles from the ramp to
the area we’d scouted as a prime fishing location near the far
end of the lake.
In most fishing situations that much fuel
would have been more than enough for a day’s fishing—even a
170-mile-plus one. We’d pre-fished the area and did it on one
tank of fuel. Not this time.
What neither of us did at the time was to take
into consideration how a lot of factors can easily cut fuel
economy by as much as 30-percent.
Granted, tournament fishing big lakes such as Lake Meade or Lake
Powell, or big rivers such as the Mississippi and its
tributaries, might not be your regular circuit. But if they are,
knowing a few little gas-saving secrets will help stretch your
bass boat’s range.
Even though it’s a lot of fun running fast and
free, there are times when being prudent and conservative play a
bigger role. Stretching fuel mileage is one of those.
For example, a bass boat’s best fuel economy
comes at the speed where it pops up on plane. For most 18- to
21-footers that cruising “sweet-spot” will be between 25- and 35
mph and somewhere between 3,000-3,500 rpm. (Think tortoise/hare
here.)
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 planing 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 practice and a good feel for how the boat is running.
If the engine is trimmed up too far the boat will usually start
porposing (the bow bouncing); 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 big blow.
Too high a bow attitude will also knock fuel
economy down a notch because the hull becomes a wall that
increases wind drag instead of a sleek wing that pierces through
the wind while adding a little lift.
The key in adjusting engine trim is finding the optimum balance
point and bow angle for whatever rpm and speed the boat is
running.
The Ranger 185VS I tested recently, for
example, running the new Suzuki DF175 four-stroke, pulled a
remarkable 6.5mpg at 3,000 rpm (26 mph.) That gave it a range of
232 miles with about 20 miles of reserve in the tank.
Rolling the throttle up to 4,000 rpm (35 mph)
dropped fuel economy to 5 mpg—effectively cutting fuel economy
by nearly 20-percent and range to 185 miles. Run the engine
between 5,500 rpm and 6,100 WOT and fuel economy drops to about
4 mpg, or a range less than 150 miles.
That’s more than a 30-percent drop in fuel
economy between optimum cruise speed and hauling the proverbial
mail.
Triton Boat’s 197 Magnum DC aluminum running
the fuel-miserly Suzuki DF150 four-stroke showed similar
numbers—although at a higher rpm because of the way the lighter
hull acts on the water. Best fuel economy came at 4,000 rpm (33
mph) with 5.5 mpg and a range of 220 miles.
Let the throttle dig deeper and the Triton pulled the
four-stroke’s fuel economy down to 4.3 mpg at 5,000rpm. Range
dropped to 173 miles. And, when the throttle was opened up to
let the engine stretch its legs (5,500 rpm/50 mph) it lost
another 10 miles in operating range, taking mileage down to 4
mpg.
Back in the mid 1990s when I began testing
bass boats, two-strokes would lose a good mile-per-gallon
between cruising speed and full throttle. Little has changed
today; a 20- to 30-percent drop in fuel economy across a boat’s
operating rpm is common, be it two-stroke or four.
Adjusting your boat’s speed, engine rpm and
trim angle aren’t the only ways to stretch fuel mileage and
reduce operating costs.
Weather and water conditions also play a role
in fuel economy. The hotter and more humid the weather, the less
power the engine makes. That typically translates into a heavier
hand on the throttle to get the boat to run like it does when
the air is cool. Hot and humid, go slow and easy.
Running into a headwind cuts into fuel economy as well. The wind
drag on a boat going 60 mph on a calm day is the same as running
50 mph in a 10 mph headwind. The same applies to current for
those river situations as does running through rough or choppy
waters.
Weight balance in a bass boat also plays a
role in fuel economy. Gear and tackle should be located with the
heaviest of it stored aft of the console to give the hull better
overall balance without having to over-trim the engine. Extra
tackle and gear that will not be used that day should be left in
the truck—or at home.
Another little performance tip is to 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 that 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 faster with
the new prop—do it.
The Boat Owners Association of The United
States (www.BoatUS.com; 800-395-2628) also offers a few tips
that are a combination of common sense and boating basics to
help stretch your fuel dollars.
They suggest anglers clean out their boat a
couple times a year. Unused fishing gear and tackle that has
been collecting mildew in the bottom of rod and storage lockers
should be left at home instead of weighting down the boat.
Another oft overlooked hindrance to
fuel-economy is running around with the livewells full of water
before you even have a bass in the boat. Think about it: Water
weighs 8.33 pounds per gallon, so a 30-gallon livewell full of
water adds nearly 250 pounds to the boat. Do you really need to
carry the weight of another angler around until there’s a
weigh-in fish to keep healthy?
Another good pointer is keeping the outboard
tuned-up. Outboards don’t run their finest when tired plugs,
injectors, carbs, filters and lubricants are doing their best to
slow it down.
Of course, here’s another money-saving tip:
Find ways to get discounts at the gas pump. For example, Boat
U.S. says many of their 800 “Cooperating Marinas” around the
country offer up to 10 cents off a gallon of gas if you show
your BoatU.S. membership card. On top of that, some of the
credit card companies offer anywhere from 3- to 5-percent on gas
purchases.
Put all of these tips into practice and you will save enough
money on gas at the end of the tournament season to buy everyone
a round of drinks at your bass club’s annual awards party.
If my fishing partner would have known his own
boat a little better, or had either of us known then what we
know now about ways to stretch a bass boat’s fuel economy, we
would have been at the weigh-in with fuel remaining in the tank
and gained enough points on the board that we’d have gladly
bought our club buddies drinks.
As it were, all we got were a lot of chuckles
when we docked and the butt of more than one joke at later
tournaments. The only thing that could have been worse would
have been coming into the weigh-in at the end of a tow rope.
