Parker Yahoo Group Archived Messages

ID From Subject Date
213 parker25lc 25'' Mod-V SC Performance Numbers 8/10/2004 9:26:00

Since I've had a while to play around with my rig and the fuel
computer that's tied into the GPS, I thought I'd post some "real
world" performance numbers.

Cruising @ 4000 RPMs gives the best overall efficiency in miles per
gallon. All told I am averaging > 2 statute miles per gallon, which
includes all running & gunning, getting onto plane, headway speed
against the tide in 5mph zones, etc. What really kills the fuel burn
is getting onto plane (that's a given), RPMs above 4400, and trying
to maintain 6 knots against a strong incoming tide (9' tides up here
in the Northeast).

At 4000 RPM running against the tide I'll be going 23 knots or better
(26.5 mph) with a fuel efficiency of at least 2MPG. Running with the
tide adds 2-3+ MPH and puts the efficiency at least 2.3+ MPG. At 5000
RPMs the boat moves out at 35-38 MPH (wind/tide dependent)and gets
1.4-1.5 MPG. WOT puts this big girl over 40MPH, pretty impressive
I'd say.

The boat is a '92 mod-V Sport Cabin with a '97 carb'd Johnson 225hp 2-
stroke on the OB bracket by Stainless Marine of Miami, FL. I think I
can raise the OB one more bolt hole. Most interesting to some of you
perhaps, I find that the Bennett TRIMS TABS HELP in ALL conditions,
whihc I am using 24" span (wide) by 9" chord (deep) tab planes. Even
in flat calm, putting the bow down a bit improves the miles per
gallon efficiency about 10%, though you really don't see the increase
in speed.

I am using the Navman 10-shade grayscale 5100x GPS plotter with fuel
transducer (the computer is built into the GPS). The neatest feature
is that once the tank is full and the system calibrated (within10%
out of the box) I can add back fuel into the "fuel remaining"
readout, say like when I bring down 20 gallons by 4 small jerry cans
to the dock. Sweet feature, even the FLoScans don't allow that ..
you need to always top off full.

Hope this helps someone pick their sweet spot for running their boat!