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Steve Helling
 
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Default Slow Cruising Speed Question

Rod,

Thought one: How accurate do you believe the speed measurements to be? If
you are basing it on the spedometer from the boat, it could be way off.


The measurements were taken with GPS, therefore accurate, except for
currents, which were averaged out given that we went several different
directions and the speeds I reported were an average. What is in question,
though, is the accuracy of the tachs, as one read 3200 while the other read
4000, and both may have been reading high. I don't remember what they read
at WOT, but believe the higher of the two read well over 5000. The owners
are currently addressing the tach situation.


Thought two: How did the boat feel at around 3200 RPMs? At 13 knots I
would expect it to be plowing big time, hard to handle, bow up high, etc.
Not a place you want to operate. Once she gets on plane the bow should

drop
and the speed pick up.


The boat, at 12 knots (3200 on the lower tach), was not on full plane, but
by 15 - 18 knots, was on plane. The bow of this boat doesn't really come up
dramatically when trying to get on plane.


Thought three: I have a 36' Carver, weighs in at about 19,000 pounds,

with
twin 350 Crusaders. I top out at about 22 knots, and can cruise at 3800

RPM
at around 18 knots. If I am not able/wanting to go that fast I drop back

to
around 1200 RPM and move along at 8 to 10 knots.

Thought four: If this is a sea trial, then I am assuming that the boat

was
pretty ba I.E., the cupboads weren't full of stuff, the water tank
probably wasn't full, there wasn't a 105 quart ice chest full of beer and
sodas on the back deck, etc. Once you buy the boat and load it up with

all
your stuff, you can bet you will lose some of the speed. If you don't

like
it now, you sure won't like it once you load it down.


This was a sea trial by myself, not a surveyor. The survey with sea trial
is coming soon. Anyway, the craft had half tanks of gas, about a half tank
of water, and the cupboards did contain quite a few odds & ends. No 105
quart cooler, though . My gut feeling, so far, is not so much that the
boat lacks power, but that the tachs are giving a false high indications, or
possibly it is not propped correctly. Hopefully, the surveyor will be able
to solve this mystery. I am also going to have the engines surveyed,
compression checked, etc.


If you want a fast boat, this doesn't sound like it. It certainly seems
like a 28 foot boat should be able to plane easier and move along at a
faster rate.

Rod McInnis