Fuel Economy, was Fountaine Pajot Cumberland 44 & Cat A rating
I don't intend to spike the conversations about the Cumberland engine choices,
nor of the presence or lack of quality boat makers, please carry on. I note,
that the Cat. A rating part of the original posting got little comment, as the
discussion moved into F. P. construction quality.
I would like to add a thread about the seeming lack of low powered 'trawler
style' power catamarans, rather like my beloved early model PDQ 34 (hull 12 of
114 sold). In these times of perpetually rising fuel costs why can't the
marketplace provide any fuel efficient (and slower, with economical motors)
models that capitalize on the real future of boating for the many of us who
face rising fuel costs with fixed or even reduced retirement incomes? Will
any of the makers recognize what I see as a clear need for Prius like
performance, rather than the headlong rush to make only larger, faster and
more powerful SUV's, Hummers and Maseratis? I don't see much in the mass
production of slender hulled power catamarans with smaller fuel efficient
engines anymore (with L/B ratios for the individual hulls in the 10 or 12 to
one range, and ondeck beam about half the length, like virtually all sailing
cats, which are after all optimized for just the speeds I'm talking about
here). I know, there are several larger efficient power catamarans made on a
custom basis, but I'm thinking of the mass production boats available to the
more modestly funded buyer. Rather the other major sort of mass produced
power catamaran which dominates the market today is the high powered, high
speed boats with distinctly planing hulls, with only a small tunnel like
passage between hulls, and performance more akin to the fast 'express' boats
and without the ability to emulate the long range trawler style cruiser, or
the well discussed motorsailer. Will the manufacturers abandon my sort of
boater leaving us to move into sailing catamarans?
The very first PDQ hulls had Westerbeke motors in the 50 hp range somewhere,
and the factory had some serious difficulties with those installations, so
they switched to the Yanmar 4JH3 55 hp normal aspiration engines. By the time
my hull was built, they were offering the 55 as standard, with the
turbocharged 75 hp as an option -- which I chose. Within a couple of years
the 75 became standard and the 100 hp intercooled turbo model the recommended
option. Interestingly, they claimed that the 100hp installations got better
fuel economy as well as pushing the top speed up a couple of knots from 19 for
the 75hp to 20kts for the 100hp.
Based on factory data, only anecdotally supported by my own experiences
(limited to measuring distances and guessing average speeds between fill-ups),
I seem to be getting 4 gal. per hour at 15 to 17 kts, which works out to
roughly 4 miles per gallon (given reasonably flat water, of course). At least
one of our loyal listees has published detailed and extensive fuel economy
data with the 100hp model. I won't quote his figures (in part because I'm too
lazy to look them up!) but I will tell about my own 75 hp experience: I get
the published WOT top speed of 19 kts in nice flat water (noted in an article
on my boat in Pacific Yachting), and a couple of times I've kissed 22 kts
(downhill with a significant tailwind). Our slender hulls don't have a
'planing step' speed that you can sense, the transition past our wave trap
hull speed of 7.8 kts seems smooth and continuous. I suspect that a peak in
fuel economy could be found if one took highly detailed fuel economy data at
such speeds, but is probably masked by the similarity between displacement and
planing behavior because it happens at down about 1/3 throttle, where there is
abundant power available, and because most of us don't spend much time
cruising there (for now). But, "the times they are a changin'."
I don't have fuel consumption instrumentation (flow meters), but I think at
least one or two other PDQ 34 owners do, and so I guess my next question is:
could one of you do a little reporting on the fuel consumption, particularly
regarding what I suspect will be a peak of fuel mileage at just below hull
speed? Are there any other makers or designers of power catamarans who have,
or could gracefully produce fuel economy data, with an eye toward nice long
ranges at reasonably low fuel cost? I further suppose that significant
changes in props would also provide gains in fuel economy -- namely putting
engine peak performance at a lower speed to promote greater range/fuel
economy, although that might effectively trim the higher speeds. Or, how
about variable pitch props? I suppose I should add flow meters and variable
pitch props to my wish list, put a little of my own money where my mouth
is...
Well, that ought to stir up a comment or two...
Regards,
Gary Bell
Dear Gary
My one year power cat is a Fountaine -Pajot Highland 35 (I suppose that is
a boat with the same concept with your PDQ 34) and either with the Volvo D2
75hp or with the optional volvo D3 110hp has a range 900-1000 miles at
7knots. My flow scan shows 0.9lit/mile at this speed. However at 15kn the
consumptios is about 1.5 lit/mile and 2 lit/mile at the top speed of 19kn.
As you see still you can find some producers that offer low consumpion power
cats
Alexander
----- Original Message -----
From: "Candy Chapman and Gary Bell" tulgey@earthlink.net
To: "Power Catamaran List" power-catamaran@lists.samurai.com
Sent: Tuesday, January 08, 2008 6:55 PM
Subject: [PCW] Fuel Economy, was Fountaine Pajot Cumberland 44 & Cat A
rating
I don't intend to spike the conversations about the Cumberland engine
choices,
nor of the presence or lack of quality boat makers, please carry on. I
note,
that the Cat. A rating part of the original posting got little comment, as
the
discussion moved into F. P. construction quality.
I would like to add a thread about the seeming lack of low powered
'trawler
style' power catamarans, rather like my beloved early model PDQ 34 (hull
12 of
114 sold). In these times of perpetually rising fuel costs why can't the
marketplace provide any fuel efficient (and slower, with economical
motors)
models that capitalize on the real future of boating for the many of us
who
face rising fuel costs with fixed or even reduced retirement incomes?
Will
any of the makers recognize what I see as a clear need for Prius like
performance, rather than the headlong rush to make only larger, faster and
more powerful SUV's, Hummers and Maseratis? I don't see much in the mass
production of slender hulled power catamarans with smaller fuel efficient
engines anymore (with L/B ratios for the individual hulls in the 10 or 12
to
one range, and ondeck beam about half the length, like virtually all
sailing
cats, which are after all optimized for just the speeds I'm talking about
here). I know, there are several larger efficient power catamarans made
on a
custom basis, but I'm thinking of the mass production boats available to
the
more modestly funded buyer. Rather the other major sort of mass produced
power catamaran which dominates the market today is the high powered, high
speed boats with distinctly planing hulls, with only a small tunnel like
passage between hulls, and performance more akin to the fast 'express'
boats
and without the ability to emulate the long range trawler style cruiser,
or
the well discussed motorsailer. Will the manufacturers abandon my sort of
boater leaving us to move into sailing catamarans?
The very first PDQ hulls had Westerbeke motors in the 50 hp range
somewhere,
and the factory had some serious difficulties with those installations, so
they switched to the Yanmar 4JH3 55 hp normal aspiration engines. By the
time
my hull was built, they were offering the 55 as standard, with the
turbocharged 75 hp as an option -- which I chose. Within a couple of
years
the 75 became standard and the 100 hp intercooled turbo model the
recommended
option. Interestingly, they claimed that the 100hp installations got
better
fuel economy as well as pushing the top speed up a couple of knots from 19
for
the 75hp to 20kts for the 100hp.
Based on factory data, only anecdotally supported by my own experiences
(limited to measuring distances and guessing average speeds between
fill-ups),
I seem to be getting 4 gal. per hour at 15 to 17 kts, which works out to
roughly 4 miles per gallon (given reasonably flat water, of course). At
least
one of our loyal listees has published detailed and extensive fuel economy
data with the 100hp model. I won't quote his figures (in part because I'm
too
lazy to look them up!) but I will tell about my own 75 hp experience: I
get
the published WOT top speed of 19 kts in nice flat water (noted in an
article
on my boat in Pacific Yachting), and a couple of times I've kissed 22 kts
(downhill with a significant tailwind). Our slender hulls don't have a
'planing step' speed that you can sense, the transition past our wave trap
hull speed of 7.8 kts seems smooth and continuous. I suspect that a peak
in
fuel economy could be found if one took highly detailed fuel economy data
at
such speeds, but is probably masked by the similarity between displacement
and
planing behavior because it happens at down about 1/3 throttle, where
there is
abundant power available, and because most of us don't spend much time
cruising there (for now). But, "the times they are a changin'."
I don't have fuel consumption instrumentation (flow meters), but I think
at
least one or two other PDQ 34 owners do, and so I guess my next question
is:
could one of you do a little reporting on the fuel consumption,
particularly
regarding what I suspect will be a peak of fuel mileage at just below hull
speed? Are there any other makers or designers of power catamarans who
have,
or could gracefully produce fuel economy data, with an eye toward nice
long
ranges at reasonably low fuel cost? I further suppose that significant
changes in props would also provide gains in fuel economy -- namely
putting
engine peak performance at a lower speed to promote greater range/fuel
economy, although that might effectively trim the higher speeds. Or, how
about variable pitch props? I suppose I should add flow meters and
variable
pitch props to my wish list, put a little of my own money where my mouth
is...
Well, that ought to stir up a comment or two...
Regards,
Gary Bell
Power-Catamaran Mailing List