Pointing
 

I have a friend who insists that longer boats characteristically point
higher than shorter ones. He doesn't have an explanation except that his
observations over the years. I wonder if this is true or if there is some
other variable (longer boats have room to sheet their headsails more
inboard, etc)

TIA,
Jack

Pointing
 

Jack wrote:

I have a friend who insists that longer boats characteristically point
higher than shorter ones. He doesn't have an explanation except that his
observations over the years. I wonder if this is true or if there is some
other variable (longer boats have room to sheet their headsails more
inboard, etc)

It might be more fruitful to discuss this issue over at rec.boats.racing but
FWIW here's my opinion: your friend is talking thru his hat. LOA has *nothing*
to do with pointing. If you want to see a graphic demonstration, take as
large a keelboat as you can muster and get into a pinching contest with a
Laser or 420.

There are a whole lot of factors that go into making a boat point high or not,
but two improtant ones are the relative size, placement, & efficiency of the
air & water foils. A boat with a baggy sprit rig can point surprisingly high
if it's underwater foils are matched to the demands of the rig, while a modern
go-fast rig will not point for squat if the centerboard/keel is not capable of
meeting the demand placed on it.

If I were to try and make a simple generalized rule, I'd say that beamy boats
with skimpy underwater foils tend to point less well. But off the top of my
head I can also think of two exceptions. You can see why I'm not a fan of this
type of vague abstract theorizing.

Fresh Breezes- Doug King

Pointing
 

However, he is right in the case of adverse conditions. A 3 foot chop that would frustrate a 25
footer and force it to foot off to keep way on, might not bother a 50 foot vessel.

--
-jeff

"DSK" wrote in message ...


Jack wrote:

I have a friend who insists that longer boats characteristically point
higher than shorter ones. He doesn't have an explanation except that his
observations over the years. I wonder if this is true or if there is some
other variable (longer boats have room to sheet their headsails more
inboard, etc)

It might be more fruitful to discuss this issue over at rec.boats.racing but
FWIW here's my opinion: your friend is talking thru his hat. LOA has *nothing*
to do with pointing. If you want to see a graphic demonstration, take as
large a keelboat as you can muster and get into a pinching contest with a
Laser or 420.

There are a whole lot of factors that go into making a boat point high or not,
but two improtant ones are the relative size, placement, & efficiency of the
air & water foils. A boat with a baggy sprit rig can point surprisingly high
if it's underwater foils are matched to the demands of the rig, while a modern
go-fast rig will not point for squat if the centerboard/keel is not capable of
meeting the demand placed on it.

If I were to try and make a simple generalized rule, I'd say that beamy boats
with skimpy underwater foils tend to point less well. But off the top of my
head I can also think of two exceptions. You can see why I'm not a fan of this
type of vague abstract theorizing.

Fresh Breezes- Doug King

Pointing
 

Jeff Morris wrote:

However, he is right in the case of adverse conditions. A 3 foot chop that would frustrate a 25
footer and force it to foot off to keep way on, might not bother a 50 foot vessel.

Sure.

But OTOH a beamy 60 footer might have to bear away a little and go for footing in a chop that might
not bother a lean mean 40 footer, or a racing multihull.

I had an "aha!" moment sailing Melges 24s in light air... once the boat was moving well, pointing
was not a problem. But the modern tiny foils (low drag, high efficiency) would simply let the boat
skid sideways and develop no power at all below a certain speed. The boat would tack through about
200 degrees, some of the time were going backwards! This is a case of matching underwater foils to
the rest of the boat... optimized for certain conditions, which of course does not include very
light air...

In the big racing multhulls, you see them going upwind with their daggerboards pulled partially up
much of the time. Same principle.

Fresh Breezes- Doug King

Pointing
 

On Wed, 8 Oct 2003 06:42:46 -0400, "Jack"
wrote:

I have a friend who insists that longer boats characteristically point
higher than shorter ones. He doesn't have an explanation except that his
observations over the years. I wonder if this is true or if there is some
other variable (longer boats have room to sheet their headsails more
inboard, etc)


You certainly have to separate variables a lot more than that simple
statement does.

Boats that are designed with pointing in mind differ quite a lot from
those designed for gentlemen. If a cruising boat uses overlapping
genoas and the shrouds prevent sheeting them at the optimum angle,
then a longer example, with proportionately less beam, would likely
point higher.


Rodney Myrvaagnes Opionated old geezer

Faith-based economics: It's deja voodoo all over again

Pointing
 

All the above is true. There are certainly many variables which you
have to sort out.

But.... Yes, bigger boats do point better, all things being
proportional. Bigger boats are more efficent -- they have less
windage per sail area, from relatively lower topsides, smaller
shrouds, and smaller masts. They get the sail up higher where there
is more wind. They have relatively less wetted surface.

Bigger boats are also more stable and have more sail carrying ability.
Therefore, in given conditions they will have more power and can trade
off speed for better pointing.

Note, by the way, that I have said "bigger" and "all things being
proportional", while you asked "longer". If you take two boats of the
same displacement, one longer than the other, all bets are off.

Jim Woodward
www.mvFintry.com

Rodney Myrvaagnes wrote in message . ..
On Wed, 8 Oct 2003 06:42:46 -0400, "Jack"
wrote:

I have a friend who insists that longer boats characteristically point
higher than shorter ones. He doesn't have an explanation except that his
observations over the years. I wonder if this is true or if there is some
other variable (longer boats have room to sheet their headsails more
inboard, etc)


You certainly have to separate variables a lot more than that simple
statement does.

Boats that are designed with pointing in mind differ quite a lot from
those designed for gentlemen. If a cruising boat uses overlapping
genoas and the shrouds prevent sheeting them at the optimum angle,
then a longer example, with proportionately less beam, would likely
point higher.


Rodney Myrvaagnes Opionated old geezer

Faith-based economics: It's deja voodoo all over again