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I have a Carolina Skiff Cat boat with twin Honda 130's on it. Each engine has an 86 gallon fuel tank. Anyone out there with the same set-up have any idea how far i could go on a tank of gas?
JCC123
This is an essential item on any boat where range is a concern. Once you determine what your fuel burn rate is at certain speeds, you will be able to determine the corresponding range, leaving some fuel remaining for emergency of course.
i dont have a ffm on my boat nor plan to get one
but i am sure they work very well and are prob-
bably revenue neutral to all who buy them....
that said, what IS essential safety equipment
on any boat is the fuel consumption rate at the
usual couple of rpms used....forget the 'TEST'
results from your magazines!!...you must measure
OUT IN THE CHOPPY REAL WORLD what you burn per
hour...this can be determined without a ffm or
anything more than a nautical chart, a tach, and
a gas guage in the tank....mine is 7.0 +/- 0.2
gal/hr at 3100-3200 rpm ...also, my tank is 115
gal nominally, but i cant put more than 105 with
out risk of spill...thus, my tank is very conser
vatively estimated at 100 gal full, and the gph
is conservatively est at 7.5....thus, i can count on 13 hours of running time and my most
conservative (considering adverse currents,
wind, and pounding) speed is 18 knots....thus,
i come up with 234 miles of range...further
rounded for absolute safety, i would never plan
any trip of more than 200 miles...i put this
out to show the vagaries of "mileage" in boats
and the proper way to handle them,ie "round down". dan
That's all well and good if your motors are always burning fuel at the same rate. But how long will it take you to figure out how to best trim your boat to maximize your fuel economy? Or to determine your most efficient speed given the all of the variables at the given time? How do you know your motors are acting differently while it's actually happening? Why guess?
You have done the right thing by paying careful attention to this issue and rounding down to be conservative. But for $150 you could take the guess work out of all of this and gain many benefits. In fact, that small investment would pay for itself in dollars, if not piece of mind in relatively short order.
agree, chessie...my most efficient speed,rpm,
and prop size were all determined before i got
the boat...i basically spec`d it out to go
most efficiently at 19 knots at 3100rpm...and
that`s is where she runs 99% of the time...dan
My Smart craft gauges just confirmed what my ears say my most effecient running speeds are, they also backed up the data I got when I used the top off method, now I use them to see how many gallons I burned per engine and look at them once in a while to make sure economy has not dropped due to old plugs or what not, I would pay closer attention on a long run to make sure I had the most fuel in reserve, I figure about 120 miles each way is conservitive enough for the 1/3 1/3 1/3 rule, even with 218 gallons.
Fuel Capacity 
