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From: Gary Bell (no email)
Date: Thu Aug 04 2005 - 19:17:11 EDT
Bob Austin wrote:
> I understand your enthusiasm for your boat. However your claim of 4
> gallons an hour at 17 knots puzzles me. A diesel engine produces 20
> hp/per gallon of fuel burned in a hour. This means that the engines
> would only be producing 40 hp at 17 knots. 17 knots is achieved at
> 3300 RPM in various sea trials on the PDQ 34. The engine curves show
> that at 3300 RPM that the 4JH3 (75 hp) consumers 3 gallons an hour per
> engine--6 gal an hour for two engines. At 3000 RPM, the engine burns
> 2 gal an engine an hour--or 4 gallons an hour. Sea trials show this
> to be closer to 16 knots.
OK. As I'm sure you will agree, sea and wind conditions have a
tremendous effect on fuel consumption figures. Plenty of other general
factors like foul bottoms and proper prop selection too. My statements
are partly based more on second hand info - from the factory and a few
'economy trials' in a couple of magazines. I also struggle with the
frankly crummy fuel gauges aboard, and most of my experience along these
lines is derived from specific trips with top-offs at each end. In good
flat water without winds, light load, clean bottom and pretty steady
speeds I have gotten right about the 4 gallon per hour figure at high
cruise speeds like the 16 kts. you suggested. In my offshore runs North
from Astoria to Neah Bay, with a heavy load, rather fuzzy bottom, plenty
of crab pots, high headwinds, heavy swells and such, I usually get right
around 100 miles on 125 gallons of fuel, and it seems to me about 9 to
12 hours, if memory serves.
>
> The real life reviews--and talking with several delivary skippers
> confirms that 3 gal an hour at 7 knots is more realistic. Even the
> runs down the ICW cannot run at the 14 knot speed because of bridges,
> and no wake zones.
Yeah, I've noticed lots of carping online about the proliferation of
slow zones on the Right Coast and much of the Gulf Coast. Here on the
Left Coast we still have mostly open water travel on the rivers and in
the Sound, etc. so speed is whatever you like. Offshore you still have
free choice of economy or speed.
>
> The cruise down the West Coast reported in the PDQ reviews show 800
> miles run, 261 gallons of fuel used and 102 hours on the
> engines--giving a speed of just under 8 knots. Again real life
> conditions of the seas and conditions going South--going North, they
> would have been bucking head winds and seas and not done as well.
I think that was an EAST Coast run. I own half the privately owned
PDQ's on the Left Coast, and it wasn't me.
> I agree it is a nice boat. My only complaint would be the bunks and
> difficulty working on the engines.
Yeah, they talk about laying above and reaching down to do engine
work. My arms are about two feet too short for that! In fairness,
stand up walk around engine rooms would be lovely but simply cannot
happen on this design of narrow hull catamaran, at least an anything
less than 60 feet or so. I do like the sound damping from the
mattresses, and perhaps if I were a good deal younger and more fit I
wouldn't exercise (exorcise?) my vocabulary quite so much.
I will soon have to confront the raw water pump impeller on the port
engine, which is #$%&* close to the outboard bulkhead. BTW, do you
know if Speedseal has one of their easy access replacement plates for
this application -- my internet search didn't exactly answer that
question. Are they a good deal? I am considering simply fitting fancy
home made thumbscrews with captive lanyards to the pump faces on my
Entec West genset and I can easily imagine doing the same on the Yanmars.
> I understand that there was some damage to three boats during the
> recent cruise to Bimini in moderate winds and seas, and that PDQ is
> stepping up to the plate to repair the boats.
I will check into that, in case there are design related issues I could
address for my own offshore confidence. They did pay for repairs and
upgrades caused by a poorly tabbed in bulkhead at the aft end of the bow
safety tank that leaked a whole lot of water when we T-boned a submerged
log and smashed the stbd bow just below the waterline. We ended up with
flooding throughout the stbd hull, halfway up the engine when I decided
to beach the boat and call Sea Tow.
>
> Regards,
>
> Bob Austin
Regards back,
Gary
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