NORDHAVN Rewrites Physics Textbooks

Well-known and well-respected motorboat manufacturer, NORDHAVN has
produced a new addition to their lineup, a 56-foot motorsailer called
the 56MS. On page 109 of SAIL magazine, October 2007 issue they have a
full-page advertisement touting how great it is.

Among other things, they claim to be able to create something from
nothing. The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power
needed to maintain the same speed the engine would produce on its own."
Huh? Tell me I ain't dreaming . . .

Now let me see if I got this straight. In dead air one assumes there is
no wind from any direction. Right? Therefore, any motion of the boat
produced by the motor in forward gear would result in an apparent wind
from dead ahead. Agreed? So, unless they've hired Old Thom Stewart, who
knows nothing about apparent wind, to write the ad script there's no way
they actually believe this nonsense that sails can be powered up by a
wind from directly ahead, is there? Seems to me the sails would just
luff and cause drag thus reducing the speed through the water produced
by the motor.

But, I guess when you're selling motorsailers you can count upon your
customers being quite stupid so perhaps some will fall for this ruse.

Wilbur Hubbard

Wilbur Hubbard wrote:

Among other things, they claim to be able to create something from
nothing. The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power
needed to maintain the same speed the engine would produce on its own."
Huh? Tell me I ain't dreaming . . .

You're not dreaming, they're right and you don't understand physics.

Is there any more help that you need?

"Steve Firth" wrote in message
.. .
Wilbur Hubbard wrote:

Among other things, they claim to be able to create something from
nothing. The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power
needed to maintain the same speed the engine would produce on its
own."
Huh? Tell me I ain't dreaming . . .

You're not dreaming, they're right and you don't understand physics.

Is there any more help that you need?

I had the utmost confidence that the post would usher forth the Looney
bin, perpetual motion crowd! Welcome, to you, sir. It's good to see a
Brit is the first to insert his foot into his mouth.

Wilbur Hubbard

On 2007-10-13 18:35:33 -0400, "Wilbur Hubbard"
said:

Among other things, they claim to be able to create something from
nothing. The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power
needed to maintain the same speed the engine would produce on its own."
Huh? Tell me I ain't dreaming . . .

Yup, that's advertising BS. If there's no wind, there won't be a
benefit while motor-sailing or any other condition.

Still, most of the time when there's too little wind for sailing,
motor-sailing will benefit from quite a few wind inputs. If nothing
else, having a sail aloft will dampen the boat's side-to-side motion
much of the time.

There are many times on the Chesapeake when having a sail up doesn't
mean squat as even a couple of knot's wind speed won't affect anything
at all.

--
Jere Lull
Tanzer 28 #4 out of Tolchester, MD
Xan's new pages: http://web.mac.com/jerelull/iWeb/Xan/
Our BVI pages: http://homepage.mac.com/jerelull/BVI/

Wilbur Hubbard wrote:

"Steve Firth" wrote in message
.. .
Wilbur Hubbard wrote:

Among other things, they claim to be able to create something from
nothing. The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power
needed to maintain the same speed the engine would produce on its
own."
Huh? Tell me I ain't dreaming . . .

You're not dreaming, they're right and you don't understand physics.

Is there any more help that you need?

I had the utmost confidence that the post would usher forth the Looney
bin, perpetual motion crowd! Welcome, to you, sir. It's good to see a
Brit is the first to insert his foot into his mouth.

Well, perhaps the idea is that when sailing into a "dead" wind, the
sails be set horizontally, so that the lift generated by them is in
the direction which is traditionally associated with "lift", i.e. "up".
Like hydrofoils, these aerofoils would cause the hull to ride a fraction
of an inch higher in the water, reducing water resistance.

Alternatively, the idea might be to back the sails, which would generate
a sideways force on the boat, so that it actually travels with some
leeway. If the leeway angle is big enough, and the drag from all this
doesn't slow down the forwards speed much, the effective speed will be
enhanced by the Pythagoras effect. The helm must be instructed to steer
a few degrees off the intended destination, to compensate for this
beneficial leeway.

On Oct 13, 12:46 pm, (Steve Firth) wrote:
Wilbur Hubbard wrote:
... The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power
needed to maintain the same speed the engine would produce on its own."
Huh? Tell me I ain't dreaming . . .

You're not dreaming, they're right and you don't understand physics.

Is there any more help that you need?

I don't have that rag and I looked at the Nordavn web site and they
don't make that claim there. If, however, the claim was made as
Wilbur represents it then Wilbur is right and Nordhavn is wrong. I'm
assuming that "dead air" means that the apparent wind is zero as seen
by an object floating freely on the ocean's surface. Over here in
the Pacific the term for that condition is "calm". As far as I know,
"dead air" means that a broadcast radio station has gone silent. I've
never heard it used as a meteorological term. Maybe the ad guy meant
"light air", in which case the claim is plausible.

-- Tom.

In article 2007101319040916807-jerelull@maccom,
says...
On 2007-10-13 18:35:33 -0400, "Wilbur Hubbard"
said:

Among other things, they claim to be able to create something from
nothing. The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power
needed to maintain the same speed the engine would produce on its own."
Huh? Tell me I ain't dreaming . . .

Yup, that's advertising BS. If there's no wind, there won't be a
benefit while motor-sailing or any other condition.

There is some benefit. Stability. Though given a calm day, one can't
imagine much of a sea state

But certainly I'm sure all would agree that motoring in nasty weather
and rough sea, a wee bit of cloth up gives a much more even ride -
reduces that horrible rolling.

--
Duncan

Wilbur Hubbard wrote:

It's good to see a
Brit is the first to insert his foot into his mouth.

Ah no, that would have been you, as usual, Craptain. I bet you think
that ice yachts can't reach 146mph either.

"Wilbur Hubbard" wrote in message
anews.com...
NORDHAVN Rewrites Physics Textbooks

Well-known and well-respected motorboat manufacturer, NORDHAVN has
produced a new addition to their lineup, a 56-foot motorsailer called the
56MS. On page 109 of SAIL magazine, October 2007 issue they have a
full-page advertisement touting how great it is.

Among other things, they claim to be able to create something from
nothing. The advert states, "Even in dead air the apparent wind when
motorsailing generates lift and reduces the amount of engine power needed
to maintain the same speed the engine would produce on its own." Huh? Tell
me I ain't dreaming . . .

Now let me see if I got this straight. In dead air one assumes there is no
wind from any direction. Right? Therefore, any motion of the boat produced
by the motor in forward gear would result in an apparent wind from dead
ahead. Agreed? So, unless they've hired Old Thom Stewart, who knows
nothing about apparent wind, to write the ad script there's no way they
actually believe this nonsense that sails can be powered up by a wind from
directly ahead, is there? Seems to me the sails would just luff and cause
drag thus reducing the speed through the water produced by the motor.

But, I guess when you're selling motorsailers you can count upon your
customers being quite stupid so perhaps some will fall for this ruse.

Wilbur Hubbard

Their claims are true. I've seen large Nordhaven motorsailers go dead into a
strong wind and rise up out of the water from displacement mode onto a full
plane.

Steve Firth wrote:
Wilbur Hubbard wrote:

It's good to see a
Brit is the first to insert his foot into his mouth.

Ah no, that would have been you, as usual, Craptain. I bet you think
that ice yachts can't reach 146mph either.

Wilbur seems to have it right this time. Either the article is
misquoted, very badly written, or just plain wrong.

An apparent wind from dead ahead can add nothing but a force directly
astern.

The case where a true wind from ahead can be used to drive a windmill
that can drive a propeller to propel the vessel is different; but this
requires a true wind.

BTW ice yachts cannot make 146mph *directly* upwind.

Andy