103.00 oil solution
My solution to the price of fuel is to mount a motorsailer rig on my new
Diesel Duck 462. I am the first Duck motorsailer built by Seahorse and should
take delivery in 2 months. I suspect that the operating paradigm will be to
keep the 135 Hp Deere ticking over at max torque/economy, and use the sails
for both stabalisation and propulsion.
When I was first thinking about this almost 2 years ago, the consensus from
TWL was that fuel is a small component of the overall cost, and don't bother
spending money on the rig. Granted wind is not free, however time will tell
if the rig was a wise decision. I suspect so.
Robert Straghan
Diesel Duck 462 - Belle
Many of us trawler types come from sailboating, and the look of sticks on boats is pleasent to the eye. Fun to play with, things to climb about on, a source of stability and a reassurance when the iron sail fails, All good,
However, windage will always be with you and have an influence in your speed, fuel consumption and have a hull reactive behavior to waves and wakes, more bob and yaw.
Ask any sailboater that took their mast off about speed and stability with and without.
Also, relative to that Deere engine, the torque peak and the best fuel use numbers are very close to one another in terms of RPM, with the non turbo 4045 that I am presently installing in my 43 lwl boat 1200-1400rpm yield .5-.75gph 220ft pounds of torque, At 2200rpm the numbers are more like 4gph and 180ft pounds.
Anyhow, a close matching of propeller size and gear reduction to hull speed and RPM at best torque and fuel use for your engine is critical--if you have doubts about diesel operation at low speeds then the inclusion of and Exhaust Gas Temperture pyrometer will help you. For the 4045D good operating temps are 900-1000F and max substained is 1150Fish-more than that means overpropped, to much junk on your bottom or to much windage.
A large prop turning slowly is the most efficient, keep prop size within 10% clearance of your appature, and tip speed below 60mph for props over 30 inches.
Wishig you following seas and pleasent winds. Kevin
Robert STRAGHAN rstraghan@hotmail.com wrote:
My solution to the price of fuel is to mount a motorsailer rig on my new
Diesel Duck 462. I am the first Duck motorsailer built by Seahorse and should
take delivery in 2 months. I suspect that the operating paradigm will be to
keep the 135 Hp Deere ticking over at max torque/economy, and use the sails
for both stabalisation and propulsion.
When I was first thinking about this almost 2 years ago, the consensus from
TWL was that fuel is a small component of the overall cost, and don't bother
spending money on the rig. Granted wind is not free, however time will tell
if the rig was a wise decision. I suspect so.
Robert Straghan
Diesel Duck 462 - Belle
http://lists.samurai.com/mailman/listinfo/passagemaking-under-power
To unsubscribe send email to
passagemaking-under-power-request@lists.samurai.com with the word
UNSUBSCRIBE and nothing else in the subject or body of the message.
Passagemaking Under Power and PUP are trademarks of Water World Productions, formerly known as Trawler World Productions.
Looking for last minute shopping deals? Find them fast with Yahoo! Search.
Kevin wrote,
"Many of us trawler types come from sailboating, and
the look of sticks
on boats is pleasent to the eye. Fun to play with,
things to climb
about on, a source of stability and a reassurance
when the iron sail fails,
All good,
However, windage will always be with you and have an
influence in
your speed, fuel consumption and have a hull reactive
behavior to waves
and wakes, more bob and yaw.
Ask any sailboater that took their mast off about
speed and stability
with and without."
I'll agree on the windage part.
However the sailboater who removed his rig decreased
stability in terms of both roll and pitch moments of
inertia.
The same would be true for a powerboat but probably to
a lesser dgree as the rig would be proportionally
smaller compared to hull.
regards,
Bill
____________________________________________________________________________________
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs
Bill, Its your basic A/B relationship (above and below waterline), If a rig is with sail engaged it dampens roll-if not the mass aloft in effect counters (deminishing the effects of) the mass below. The addittional distance from waterline of the above mass may reach say 65ft, as opposed to 6.5ft below waterline for the keel which multiplys its influence (although significantly less weight). Also the wigglw/waggle (a non-nautical term) of the keel in the more viscous H20 as compared to less so air has its influence.
Add these stabilizing influences plus frictional air resistance forward under power,, sticks in the air unattended are a a fuel cost in terms of NMPG, that is except in following winds-then they help. Hoping for fair winds aft, but without exhause fumes. Reguards.Kevin
Kevin said
Ask any sailboater that took their mast off about
speed and stability
with and without."
Bill said
However the sailboater who removed his rig decreased
stability in terms of both roll and pitch moments of
inertia.
Never miss a thing. Make Yahoo your home page.
http://www.yahoo.com/r/hs
http://lists.samurai.com/mailman/listinfo/passagemaking-under-power
To unsubscribe send email to
passagemaking-under-power-request@lists.samurai.com with the word
UNSUBSCRIBE and nothing else in the subject or body of the message.
Passagemaking Under Power and PUP are trademarks of Water World Productions, formerly known as Trawler World Productions.
Never miss a thing. Make Yahoo your homepage.
Hi Kevin,
"Its your basic A/B relationship (above and below
waterline), If a
rig is with sail engaged it dampens roll-if not the
mass aloft in
effect counters (deminishing the effects of) the mass
below."
Disagree. The moments, pitch and roll, are
established by the distance of mass from the center of
gravity, above or below the wl. Or to the sides for
that matter.
Picture the skater on ice, in a spin with arms
extended; slow. Pull in the arms, still spinning,
faster. Or the rope walker with a balance pole. The
pole dampens motion.
"The
addittional distance from waterline of the above mass
may reach say 65ft, as
opposed to 6.5ft below waterline for the keel which
multiplys its influence
(although significantly less weight)."
Agree the distance multiplies the effect of weight.
If you put a 10# weight at a height of 65' above the
center of gravity, it will have the same roll
dampening as 100# placed 6.5' below the center.
Check out some of the conclusions from the 79 Fastnet
regarding which boats rolled more esily, masted or
dismasted ones.
Best regards,
Bill
____________________________________________________________________________________
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
So the real issue here is to be more effective with the platform we have or intend to own-to go back and forth on the sail issue is like,get a sail boat don't compromise a power boat--what can I say?
Get a nose job--a David Taylor Bulb Bow. Why do those 1890 Spanish boats with raming thingies up front do better than our Great White Fleet? Admiral Taylor asked-and endevored to find out by buiding Model Basins to check out how and why. I live next door to the Model basin in Maryland.
What does a bulb bow do?
It increases waterline lenght-and thats good.
It reduces pitching, Slower up, Slower down.
It predisposes bow wave.
Makes people ask-whats that thing up front.
How do I get one--Buy a Nordhaven
Hire a NA and a test tank
Glue one on the front of your boat.
Its not that hard, You can buy nice/strong fiberglass tanks in various diameters/lenghts say 18 inches by 4 feet, cut it to match your bow, fill it with foam, bond and fair it in. Done.
If you dont like the result cut it off-or change its shape (pointy on the bottom/flatter on top)
Make it thicker or longer by slipping/bonding the next larger diameter, copy some other boats design. Have a blast with fiberglass.
On a Boat like mine with a traditional 40ft. waterline and 43 deck lenght, 2.5ft more on the waterline forward from the bulb and .5Ft extension on the rudder gives me a 43ft waterline--a 5-10% effeciency increase, less pitch,lots to talk about at the docks. You can paint it like shark teeth, spirials, things with eyes.
All for less than the cost of a single sail, about two days work, $1000ish dollars.
Don't you all get your nose out of joint, with 200,000 miles with this approach, it works.
Food for thought,Kevin
Be a better friend, newshound, and
know-it-all with Yahoo! Mobile. Try it now. http://mobile.yahoo.com/;_ylt=Ahu06i62sR8HDtDypao8Wcj9tAcJ
http://lists.samurai.com/mailman/listinfo/passagemaking-under-power
To unsubscribe send email to
passagemaking-under-power-request@lists.samurai.com with the word
UNSUBSCRIBE and nothing else in the subject or body of the message.
Passagemaking Under Power and PUP are trademarks of Water World Productions, formerly known as Trawler World Productions.
Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now.
Kevin asked: What does a bulb bow do?
It goes SLAP SLAP SLAP SLAP as it enters and exits the water over and
over and over and over again. Try one before you buy one.
Scott, Alanui, N40II, Seattle
currently in Puesta del Sol, Nic.
I would suggest looking very carefully at other boats in the sub 60 foot
range before adding any bulbous bow protuberances to a sub 60 foot boat.
That is about the lower range of usefulness.
John Harris
--
I am using the free version of SPAMfighter for private users.
It has removed 25 spam emails to date.
Paying users do not have this message in their emails.
Get the free SPAMfighter here: http://www.spamfighter.com/len
I would suggest looking very carefully at
other boats in the sub 60 foot
range before adding any bulbous bow
protuberances to a sub 60 foot boat.
That is about the lower range of usefulness.
I believe Nordhavn/PAE toyed with bulbous bows in the
early N46 models. While I hesitate to speak for their
conclusions, I assume they did not find the
efficiencies they had hoped for which is why the
appendage was abandoned in the N46's, and didn't
appear in the N47's, N43,s N40's, etc. I can tell you
from personal experience with N57's that the bow slap
that Scott mentions is extremely annoying when heading
to weather. My guess is that the water 'claps' when it
rejoins atop the bulb (or perhaps slaps the hull) and
makes a rather thunderous noise throughout the boat.
While there's no structural downside to it, it can be
really annoying after a few days. I personally
wouldn't have one on a boat, but its a personal thing.
I have never read anyting to suggest an efficiency
improvement of more than a couple percent, even in
large ships. For a large ship burning tens of
thousands of gallons of fuel a year, for 30 +/- years,
a 2% improvement adds up. For a recreational boat -
even heavily cruised, I doubt it makes financial
sense.
At the risk of getting beyond my technical tether in
boat design, I suspect a better place to look for
efficiencies is properly matching the hull form to the
desired speed/engine/displacement factors. I believe
the naval architects refer to one aspect of this as
Prismatic Coefficient ('PC' - there are probably other
parameters too). My guess is a properly designed hull
matched with optimized machinery operated within it's
design parameters will be the most efficient option in
the size range we are dicussing.
Peter
W36 Sedan (no idea what my PC is)
San Francisco
=======================
Peter Pisciotta
415-902-8439
I seem to remember reading one architect opinion around Bulbous Bows: For
the cost associated with fitting one to small boats of our size, it was
better to just extend the length of the whole boat 2'. Gaining the same
'efficiency' improvements that a BBow would give to a shorter boat, and also
providing the benefits of more usable space.
-al-