Re: [PUP] Motor+sailer vs Motor-or-Sailer
Kevin,
You make an excellent point and a contributing factor to why many previous designs where good at neither. I think a key shift in philosophy is one represented by Paine's SteadySailer which has the design goal to maintain 10 knots through the combination of wind AND diesel power in a ratio dictated by the current conditions. A variation on this theme are some of the experiments with diesel-electric where you generate power off the prop when you have excess wind power. By freeing yourself of the requirement to be able to achieve maximum performance on sail alone, resulting in smaller than optimal prop, you can also reduce the size of the rig (or kite). And a small reduction in rig can cause a significant reduction in loads and cost.
As others have said, you can buy a lot of fuel for the cost of a rig and sails, but we are not shipping cargo here, so economics isn't the end all and be all. Sometimes you want to surge of surfing down a wave in the trades at twilight, sometimes you just want to get where the wind ain't takin' ya.
Mark
Marina del Rey, CA
----- Original Message ----
From: Kevin Kearney lotusman1951@yahoo.com
To: passagemaking-under-power@lists.samurai.com
Sent: Monday, March 19, 2007 5:51:41 AM
Subject: [PUP] Motorsailers
I own and cruise a Sutton (Tarpon Springs) LWL 43 LOA 47 1966 steel Trawler originally equipped with 2 masts and sails then converted to paravanes, sticks deleted, sails sold, 200,000 logged miles 5.5mpg, 900 gallons fuel, MAN 4 liter-detuned by the factory from 90hp to 44hp-1500rpm tops, cruises at 7.1 knots 1200rpm-30,000 engine hours-oil changes recommended by the factory for every 900 gallons of fuel used--low wear long life. So an experienced boat. Point being other than the complexity of a folding prop how well do you think my current 34 inch 3 blader-5% more efficient than my 32 incher is going to do sailing. Sort of like dragging a garbage can behind the boat I suppose. Efficient Trawlers have large props, sailboats have small props. Making windage from sticks and sailing efficiency from prop and appature size reduces range increases fuel usage and isn't that beyond a "get home system" that all this babble about motorsailers is focused at. JOLIE
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Kevin said: I think a key shift in philosophy is one represented by Paine's
SteadySailer which has the design goal to maintain 10 knots through the
combination of wind AND diesel power
Scott retorts: This posting is an example of exactly what has gone wrong in
the last few days. Because we have opened the door to the discussion on
Sail we are loosing focus on the content of this forum. It's no surprise to
me that sailors are discovering adding power makes sense. This is not a
Adding Power to Sail forum. We don't use our props to generate power when
there is lots of wind. There are innumerable forums for sailors to debate
these topics.
Please, we need to return to the focus of this list, Beebe realized the
sails on his boat were worthless after building and voyaging Passagemaker,
to quote:
Voyaging Under Power, Third Edition Lessons Learned, page 34, Sailing Rig.
This feature is hard to justify by the facts of our cruising. It is not a
good emergency propulsion system for this reason: If the engine should
fail, sail would get you somewhere, but the chances of its being where you
wanted to go are pretty slim. consequently, your cruise would be pretty
well ruined, while an alternative power system would allow the cruise to
continue. In addition, an efficient sailing rig is expensive-more so than
another diesel engine.
Please, if there is sufficient interest in establishing a multi-hull power
assisted sailing forum, then someone should approach Georgs and see if he's
interested in hosting one. For the Passagemaking Under Power forum, we
propel the boats with diesel engines (or hybrid diesel electric). The
primary propulsion is not sail with the motor ticking over.
Scott Bulger, PUP List admin
Scott:
Thank you.
You might have an idea of how many
responses I have not even bothered to read
and just deleted them.
There was one exception.
Any e-mail generated by you was read.
I feel I owe it to you and frankly, even you were
getting sidetracked by the bovine fertilizer being
spread throughout the pace. It was staring to smell
where I had to grow up and muck out the stalls
and move that effluent out to the spreader.
If someone does not know of what I speak,
too bad, it was an integral part of my growing up.]
It taught me how to separate bovine fertilizer from
apple butter. Both of which are a necessary part
of growing up on farm. Neither of which is germane
to this forum.
Keep up the faith.
Someone, like you, has to take
the tiller occasionally and steer it back on course.
Thanks, again
Regards,
Rick Redfern
--- "Scott E. Bulger" scottebulger@comcast.net
wrote:
Kevin said: I think a key shift in philosophy is
one represented by Paine's
SteadySailer which has the design goal to maintain
10 knots through the
combination of wind AND diesel power
My apologies for protracting this discussion, but this comment caught my
attention:
"... (A sail on a power boat) is not a good emergency propulsion system for
this reason: If the engine should fail, sail would get you somewhere, but
the chances of its being where you wanted to go are pretty slim...."
I confess to being someone who has never been comfortable around lightning.
There is something appealing to the idea of a backup system that requires no
fuel or electricity. In a perfect world, I'd have a backup diesel engine,
with its' own prop and fuel supply, AND a mast that would be my ultimate
fall-back position. I'm assuming that power boats are not designed to be
great sail boats, but why wouldn't 2 knots be a step up from 0 knots? Your
posting seems to imply that such a setup would be un-maneuverable. Is this
necessarily true? Feel free to ignore this posting if this just re-opens the
whole debate (which I personally thought was very educational!).
Ken Williams
Sans Souci
Nordhavn68.com
Ken asked: I'm assuming that power boats are not designed to be
great sail boats, but why wouldn't 2 knots be a step up from 0 knots? Your
posting seems to imply that such a setup would be un-maneuverable.
Scott replies (clearly with no credibility, so he waits anxiously for Bob or
others to confirm or correct): Yes Ken, it would be virtually
un-maneuverable. This isn't me talking it's Beebe and others. For a
downwind/trade wind route, you might be able to move the boat. Perhaps a
kite could get you 20 to 40 degrees off dead downwind (despite 100 google
attempts and an hour of reading, I couldn't garner any info on the
non-downwind performance of the kites?)? Hell, if you go long enough your
going to hit a continent someplace, so maybe that's the rational of the kite
or sale for backup?
The point of a Diesel Passagemaker is you put the effort to back the
propulsion up via a second source of POWER. Your a floating storage tank
full of dead dinosaurs anyway, so put it to use. If lightning is your
primary concern (a fear of mine as well, perhaps irrational, like my fear of
pirates, arrg) put some time into a way to isolate the wing engine. Crap,
all it needs is a way to turn it over and fire and a supply of fuel and it's
going to turn the prop. A single surviving 8D and a set of jumper cables
should get the thing to fire. Your hand held GPS and sole surviving laptop
with your back up charts is going to get you where you need/want to be.
Assuming no one is hurt in the strike, hopefully your biggest problem is the
watermaker and freezer are dead so you have to ration water and eat
everything before it spoils, then it's top ramen for the rest of the journey
to port. Of course this may mean, if you have elected to have a non
hydraulic steering system (damn those copper flair fittings!) and it's dead
you might be standing in the cockpit steering the rudder by hand :)
Point is, your not praying a boat comes along so they salvage you and lay
claim to your beautiful boat. Be it a genset with PTO swinging your prop or
a wing engine with a nastily asymmetric thrust that causes you to steer with
the rudder at 20 degrees, some form of ozone depleting, global warming
contributing, sooty internal combustion process is going to bring you home.
And Thank the Gods for that!
Scott.
Now this is a reasonble discussion!
I'm assuming that power boats
are not designed to be
great sail boats, but why wouldn't
2 knots be a step
up from 0 knots?
We had a 200 sf genoa flying on Patrick Gerety's
Willard 40 "Aloha" in the hopes of being the first
powerboat to cross a finish line in this years Baja
Ha-Ha. With beam winds in the high teens and flat
seas, we were hopeful we could sail this sail-similar
hull form.
Despite the best-case scenario (and the sailmaker's
prediction of 3-4 knots), speed dropped well below
2-knots. Steerage did not exist. I believe this is an
adequate definition of being adrift.
There are several reasons to recommend putting sails
on a trawler but back-up propulsion is not one of
them. At least I haven't seen evidence to support the
idea.
Peter
PassageMaker had an article about an iconoclast in the PNW who built a big
blue trawler with sails. As I recall, it did well.
Ron
One has to ponder whether a mast high enough to support sails would increase
the likelihood of a lightning strike. There was an article in PassageMaker
Magazine awhile back which featured a blue trawler that was maybe 45 feet in
length and was designed with sails, but not a motorsailer. He got a good
turn of speed from the sails.
Lastly, Buehler and Kasten for example offer designs with a sail plane.
Surely they think these sails will move the boat.
Ron Rogers
----- Original Message -----
From: "Ken Williams" kenw@seanet.com
Sent: Tuesday, March 20, 2007 1:14 AM
Subject: Re: [PUP] Motor+sailer vs Motor-or-Sailer
| My apologies for protracting this discussion, but this comment caught my
| attention:
|
| "... (A sail on a power boat) is not a good emergency propulsion system
for
| this reason: If the engine should fail, sail would get you somewhere, but
| the chances of its being where you wanted to go are pretty slim...."
|
| I confess to being someone who has never been comfortable around
lightning.
| There is something appealing to the idea of a backup system that requires
no
| fuel or electricity.
Lastly, Buehler and Kasten for example offer designs with a sail plane.
Surely they think these sails will move the boat.
R
If it takes 10-50 horsepower or so to move a small cruising boat, that
can be translated into pounds of pull. That can be figured into so many
square feet of sail area times so much wind speed. In other words, 10
knots of wind times 300 feet of sail area equals say 10 horsepower
(that's not the correct numbers, but you get the idea.).
It takes so much lever arm to make the boat stand upright or nearly so
for each 10 horsepower of wind, call it ballast. It takes so much
lateral resistance to keep the boat from sliding sideways, the more
lateral R the more directional control you can anticipate.
If you keep on adding sail area, then it takes more ballast to keep the
boat upright. More sail area also requires more lateral resistance,
commonly called keel. The more sail, the more wind, the more keel the
closer you are to a "Sail" boat. This is not rocket science and the
factors that are required are pretty well known and have been since the
early 1930's.
By the way, the more wind resistance from say a high cabin the more
horsepower it takes to make the boat go. Which means, more sail, more
ballast, more keel. You can see where this leads. At some point there is
vanishing point where there is almost no additional advantage that can
be gained.
Regards,
Mike
Capt. Mike Maurice
Beaverton Oregon(Near Portland)
Ron stated: Lastly, Buehler and Kasten for example offer designs with a
sail plane.
Surely they think these sails will move the boat.
Scott suggests: I don't believe your assessment of George Buehlers opinion
of sails is accurate. You might drop him a note and ask. I might be wrong,
but I might be right ;)
Scott