Chris Newport wrote:

On Wednesday 25 August 2004 12:26 am in rec.boats.cruising Parallax wrote:


A related issue is that most sailboats have a fairly small engine
intended only to get the boat up to hull speed in calm water. Putting
in a larger engine would be considered wasteful because then the boat
would have to always carry around that heavier engine even when it
wasnt needed. Is it possible to temporarily increase the power
outpuit of a small engine by some means, perhaps a blower, a turbo or
even using NOS? This might give the sailboat the ability to better
motor off a lee shore in strong winds, motor against a strong running
tide, etc. I am primarily interested in times when it is a safety
issue, not for convenience so potential engine damage might be
acceptable.


If the hull is not designed for planing under power you
will not be able exceed the hull speed, so more power is
a waste.

Twaddle.

More power = more speed. The hull speed calculation simply implies
what speed you might find most economical. Slower is cheaper, except
for time. Time is money. Kind of like relativity. Is time cheap?

Sail off of a lee shore. Don't buy a sailboat that can't. If it is
tough, even a little boost from an engine will make the difference.
When the wind comes up, reduce sail. Too much wind power makes a
sailboat difficult to maneuver. All boat hulls are sailboats. Most
sailboats can be sailed without their sails.

Look a little further up the road (seaway). Keep out of trouble
instead of trying to get out of trouble.

That's Pilot's rule #1!

Too bad automobiles don't follow the COLREGS! Pedestrians have the
right of way even on the water.

Terry K

Terry Spragg wrote:
Chris Newport wrote:
If the hull is not designed for planing under power you
will not be able exceed the hull speed, so more power is
a waste.

Twaddle.

More power = more speed.

This has an asymptotical limit, though.

Andreas.

--
Dr. Andreas F. Borchert, SAI, Universitaet Ulm | Habe Mut, dich deines
Helmholtzstrasse 18, E02, Tel +49 731 50-23572 | eigenen Verstandes zu
http://www.mathematik.uni-ulm.de/sai/borchert/ | bedienen! -- I. Kant

On Friday 27 August 2004 10:23 am in rec.boats.cruising Andreas Borchert
wrote:

Terry Spragg wrote:
Chris Newport wrote:
If the hull is not designed for planing under power you
will not be able exceed the hull speed, so more power is
a waste.

Twaddle.

More power = more speed.

This has an asymptotical limit, though.

Given enough thrust, pigs fly just fine; although this is
not necessarily a good idea.

--
My real address is crn (at) netunix (dot) com
WARNING all messages containing attachments or html will be silently
deleted. Send only plain text.

More power = more speed.

This has an asymptotical limit, though.

bull****, doc. you may well know what the the word "asymptotical" means but
you don't know squat about the shape of the power curve of a boat at or
anywhere near hull speed.



Andreas.

--
Dr. Andreas F. Borchert, SAI, Universitaet Ulm | Habe Mut, dich deines
Helmholtzstrasse 18, E02, Tel +49 731 50-23572 | eigenen Verstandes zu
http://www.mathematik.uni-ulm.de/sai/borchert/ | bedienen! -- I. Kant

More power = more speed.

This has an asymptotical limit, though.


JAXAshby wrote:
bull****, doc. you may well know what the the word "asymptotical" means but
you don't know squat about the shape of the power curve of a boat at or
anywhere near hull speed.

Why don't you explain it to us, Jaxxie?

Most of us could use a good laugh.

DSK

More power = more speed.

This has an asymptotical limit, though.


JAXAshby wrote:
bull****, doc. you may well know what the the word "asymptotical" means
but
you don't know squat about the shape of the power curve of a boat at or
anywhere near hull speed.

Why don't you explain it to us, Jaxxie?

Most of us could use a good laugh.

DSK

here you go, dougies.

as·ymp·tote ( P ) Pronunciation Key (sm-tt, -mp-)
n.
A line whose distance to a given curve tends to zero. An asymptote may or may
not intersect its associated curve

On 27 Aug 2004 11:23:29 +0200, (Andreas
Borchert) wrote:

Terry Spragg wrote:
Chris Newport wrote:
If the hull is not designed for planing under power you
will not be able exceed the hull speed, so more power is
a waste.

Twaddle.

More power = more speed.

This has an asymptotical limit, though.

Andreas.

Hmmm...asymptotic graphs usually present in some form like
y = 1/x
aren't they?

I suspect you have in mind a characteristic of this kind:
y = 1 - exp(-x)

Brian Whatcott Altus OK

Parallax wrote:
Cruising sailboats and powerboats have very different ideas on fuel
use and the needs of the sailboat are rarely addressed. For example,
most powerboaters are very concerned about the overall cost of the
fuel they use primarily because they use a LOT of fuel.

That depends very much on the powerboat. Most "cruising" powerboats are
relatively economical. For example, in the 2 years we've owned & cruised
(several thousand miles) our 36' power boat, we've spent far less on
fuel than we did on a slip to keep it in. Or insurance.

OTOH if you want a POWER boat, twin engines & big wakes and all that,
then yeah, fuel is going to cost a lot. I hear guys with big
sportsfisherman talk about burning 30 gph, or ~ $500 day. Ouch!


Most sailboats have a smaller engine for their displacement than a
powerboat because their primary power is supplied by free wind.

I dunno, for the cost of a new genoa or cruising spinnaker for a boat of
similar size to ours, I could buy 5,000+ miles worth of fuel.


However, fuel use (hp/liter or hp/ounce) and overall power sometimes
are important for a sailboat. A long distance cruiser can only carry
a small amount of fuel and if he has a long period of no or contrary
wind, he might want to be able to motor for a long time with little
regard for the cost of the small amount of fuel.

Yep. That's why a *sailboat* should have good light air and upwind
performance. Most people don't have the patience, or the time; that's
ignoring a large group that don't have the skills or the inclination.
And most people want to bring along all the comforts of home on a boat
barely big enough to hold them, which also degrades sailing performance.


... So, are fuel additives available
that would effectively increase the hp/ounce of fuel burned even if
they greatly increase the overall fuel cost? Would octane boosters
help (or cetane boosters)?

There are a lot of fuel additives, but they typically cost more and
don't improve fuel performance enough for your purpose.


... Is it possible to temporarily increase the power
outpuit of a small engine by some means, perhaps a blower, a turbo or
even using NOS?
... This might give the sailboat the ability to better
motor off a lee shore in strong winds

Usually the problem with motoring off a lee shore is
1- prop out of the water
2- engine sucks air into cooling system.
3- crap in fuel gets stirred up & clogs filters.

So increased power isn't going to help a thing.

Maybe if you're interested in increased range & efficiency you should
try one of those electric drives with battery bank and solar panels? Or
if you just want to go fast, get a speedboat.

Fresh Breezes- Doug King

Subject: fuel use for sailboats
From:

Cruising sailboats and powerboats have very different ideas on fuel
use and the needs of the sailboat are rarely addressed. For example,
most powerboaters are very concerned about the overall cost of the
fuel they use primarily because they use a LOT of fuel. Cruising
sailboats are not terribly concerned about the overall cost of their
fuel because they will always use a small amount.
Most sailboats have a smaller engine for their displacement than a
powerboat because their primary power is supplied by free wind.
However, fuel use (hp/liter or hp/ounce) and overall power sometimes
are important for a sailboat. A long distance cruiser can only carry
a small amount of fuel and if he has a long period of no or contrary
wind, he might want to be able to motor for a long time with little
regard for the cost of the small amount of fuel. He might consider it
rreasonable to pay a premium for a fuel that was formulated to produce
more more power for ounce of fuel burned even if that fuel was twice
as expensive as conventional fuel. So, are fuel additives available
that would effectively increase the hp/ounce of fuel burned even if
they greatly increase the overall fuel cost? Would octane boosters
help (or cetane boosters)?
A related issue is that most sailboats have a fairly small engine
intended only to get the boat up to hull speed in calm water. Putting
in a larger engine would be considered wasteful because then the boat
would have to always carry around that heavier engine even when it
wasnt needed. Is it possible to temporarily increase the power
outpuit of a small engine by some means, perhaps a blower, a turbo or
even using NOS? This might give the sailboat the ability to better
motor off a lee shore in strong winds, motor against a strong running
tide, etc. I am primarily interested in times when it is a safety
issue, not for convenience so potential engine damage might be
acceptable.
Any ideas?







Subject: fuel use for sailboats
From: (Parallax)

I am very aware of the limitations on hull speed. What I mean is that
sometimes an engine that will enable you to achieve hull speed in calm
water will only allow you to do half in wind or current. The idea is
to get more power to achieve nearly hull speed for short time when
conditions are such that you would otherwise be going slow. I rarely
buy my diesel at a marina as I dont ever seem to be near a marina.
Normally, I buy fuel and carry it to my boat. In this case, getting a
NOS canister would be reasonable. I agree, NOS simply adds extra
oxygen allowing more fuel to be burned thus producing more power.
Although I have used starting ether when I lived in WY in winter, I do
not think it adds any power, it is simply an easily ignited gas to get
the motor turning.

I am also aware of what octane does and I simply used it as an example
of an additive. My question is, are there additives available, sucha
s long chain hydrocarbons that would give more power than just gas
even though the additive might be very expensive


These are two of the funniest troll posts I have read in a long time. LMAO

Hell, he even sucked jaxas in. LOL

Capt. Bill

yeah, sure. anything you say.



Date: 9/1/2004 6:20 PM Eastern Daylight Time
Message-id:

On Wed, 01 Sep 2004 14:55:48 -0400, DSK wrote:

Please explain further... the power/speed graph can reach infinity on
both axes? Does this mean that we can have negative horsepower? That
would make for excellent fuel efficiency!


Meindert Sprang wrote:
Sigh! With both axes I mean X and Y axis. And in our case only in the
first
quadrant, where X and Y are positive.

Dammit, another great idea shot down... I thought we could have a boat
where if you put the engine in gear while you were sailing, it would
actually *produce* fuel.


Actually, it's a reality. There are now electric aux motors that can recharge
battery banks by putting the drive in gear while sailing. Just one more thing
about boats you don't know. I'm a little surprised about this one, because
I'm
sure it's been mentioned in the magazines where you get most of your
"knowlege"


BB