Any thoughts onhow to make this boat better
 

In article ,
says...

"DSK" wrote in message
. ..

Well there you go again. The water ballast is not "in water"
it is in the boat. Will no amount of repetition get this
point across? You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?


Dave just doesn't get it.
And he refuses to do any experiments because he is afraid of
water.

Perhaps you should contact Boeing and get them to replace the depleted
uranium couterbalances with water ballasts.

--
Duncan

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote in message
Not a lot no. However if you use something that's heavy. You
can use
feathers if you like - good luck.


I understand that feathers weigh nothing once in the air.

SBV

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote in message
Perhaps you should contact Boeing and get them to replace the
depleted
uranium couterbalances with water ballasts.


Gee Dunc, what's next, steel weighs more than aluminum?

Prof. Scotty

Any thoughts onhow to make this boat better
 

"Commode Joe " wrote in message
...
On Thu, 12 Jan 2006 20:41:50 -0500, "Scotty"
wrote:


"Dave Doe" wrote in message
Not a lot no. However if you use something that's heavy.
You
can use
feathers if you like - good luck.


I understand that feathers weigh nothing once in the air.

SBV



You understand wrong, dopewad.


Cripes! I didn't even tie a hook on my line yet and this jerk is
biting already.

SV

Any thoughts onhow to make this boat better
 

In article ,
says...

"Dave Doe" wrote in message
Not a lot no. However if you use something that's heavy. You
can use
feathers if you like - good luck.


I understand that feathers weigh nothing once in the air.

Indeed, infact if you were to hang on to some feathers with the right
breeze, you'd have to *hold* them *down*. Just like gliders, they can
indeed go up.

You clearly have no idea what MASS and DENSITY are about.

--
Duncan

Any thoughts onhow to make this boat better
 

In article ,
says...

"Dave Doe" wrote in message
.
Indeed the water ballasting *only* has positive righting
moment
if the
boat is pushed over to where the centerline is above the
waterline (a
fair way!).


Bzzzzzzt! You are wrong Dave.

Nice evidence.

This is ASA, no evidence necassary.




PS: if yer don't believe me, fill a milk carton with water
and
play with
it in the bath


A scientific study if ever there was one.

It sure *is*.


Take a 5 gallon jerry jug, put 5 gallons of water in it. Will it
float? Take that same 5 g. jug and put the same weight ( approx.
40 lbs.) in of lead. Will it float? Which floats higher?
Conclude which is heavier? Make sure you wash behind your ears.

Scotty

Can you sink a 'positive buoyancy' boat with water? Can you sink it with
lead? You've proven my own point.

--
Duncan

Any thoughts onhow to make this boat better
 

.... You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?



Well?
How about an answer on this one?


Let me propose this example- a cooler full of ice & beer is
lighter than water (hence lighter than water ballast) yet
can be pretty heavy when you're carrying it down the dock.
If you put it in the lowest possible location in the boat,
right down against the hull, and tie it in securely (to the
handles, so you can still open the lid of course), will this
improve the boat's stability?


Dave Doe wrote:
Not a lot no.

Which means yes.

Ah good, so now we've gone from "Water cannot be ballast
because it doesn't weigh anything when below the waterline"
to admitting that something that is in fact lighter than
water *can* function as ballast below the water line,
although not as efficently as denser material.

Think it over some more. I compliment you on your ability to
gradually recognize facts contrary to your prejudices. Most
people can't ever take this first small step.

DSK

Any thoughts onhow to make this boat better
 

In article ,
says...
Are you saying that the water ballast inside a boat hull
does not affect it's stability? That the water ballast
"weighs nothing" until it is above the waterline?


Dave Doe wrote:
Nope, never did. I'm saying it's stability is indeed improved (more
mass to move)

That would be an issue of inertia... dynamic stability, if
you like the term.

ie stability.

... but question its righting ability vs lead keel - and
posed a question about that.


Well, I don't think that anybody has claimed that water
ballast provides equal righting moment to external lead
ballast. But it can provide significant righting moment,
especially if the boat is designed from the start to utilize
water ballast effectively.

Provide some evidence.

The problem is that water in the ballast has the same density of the
water it is in

Well there you go again. The water ballast is not "in water"
it is in the boat.

Where is the boat?

Will no amount of repetition get this
point across? You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?

Let me propose this example- a cooler full of ice & beer is
lighter than water (hence lighter than water ballast) yet
can be pretty heavy when you're carrying it down the dock.
If you put it in the lowest possible location in the boat,
right down against the hull, and tie it in securely (to the
handles, so you can still open the lid of course), will this
improve the boat's stability?

What is your point? Put feathers in the bottom of your boat? Or put
water? Or go deeper 1and put lead? I think you need to consider the
basics when considering a sailing vessel; water on or about the
centerline is a waste of potential that is even more easily achieved
otherwise. It is the same density of the stuff you're moving through -
it's a very major factor, as you're floating on it. Consider the
obvious. When the boat is on an angle the only force the water can
exert is on the air below it and not the water (it exerts no effective
force on the water if you can get your head around that). And that is
only because it is held there in it's ballast tank and not allowed to
'seek it's natural place at the bottom' (it's heavier than the
surrounding air - but please don't dissregard the whole equation - what
the boat is in).

Consider the absurd, a boat of no mass other than its water ballast. It
will sit in the water, level with the ballast waterline. If you are to
heel it - well you work it out. The maths is easy, consider the water
ballast as a "solid" (as it cannot move).

Then consider the same mass many times denser at a point well beyond the
fulcrum point the water ballast is on.

Also think of boat speed and drag (wetted area).

Short of moving magically moving the water ballast from one side to the
other - same as the tack - water ballast is a crock.

It's a lot heavier than air, but look at "what you're doing" and the
alternatives.

Come on - do my maths (example question posed already, no answers yet)

--
Duncan

Any thoughts onhow to make this boat better
 

In article ,
says...

"DSK" wrote in message
. ..

Well there you go again. The water ballast is not "in water"
it is in the boat. Will no amount of repetition get this
point across? You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?


Dave just doesn't get it.
And he refuses to do any experiments because he is afraid of
water.

Is the water in a plastic floating in the ocean:
a) in the plastic bag?
b) in the water?

Well technically, it's in the plastic bag. Is the plastic bag a factor?
No.

--
Duncan

Any thoughts onhow to make this boat better
 

Dave Doe wrote:
Nope, never did. I'm saying it's stability is indeed improved (more
mass to move)

That would be an issue of inertia... dynamic stability, if
you like the term.


Dave Doe wrote:
ie stability.


There is a difference between static stability ei righting
moment, and dynamic stability or roll resistance. The first
is relatively simple, the latter vastly complex and
influenced by underwater foils, distribution of mass,
distribution of hull volume & reserve bouyancy, etc etc.

Correct me if I'm wrong, Dave: you started out by saying
that water ballast cannot generate righting moment.



... but question its righting ability vs lead keel - and
posed a question about that.


Well, I don't think that anybody has claimed that water
ballast provides equal righting moment to external lead
ballast. But it can provide significant righting moment,
especially if the boat is designed from the start to utilize
water ballast effectively.


Provide some evidence.


That lots & lots of water ballast boats are out there
sailing? That I've personally sailed about a dozen boats
with water ballast, and found them to have no significant
difference in the way they sail compared to lead ballasted
boats?

For example, we owned & sailed a 19' water ballasted sloop
for eleven years. Many times at club get-togethers, people
would say "Is a water ballast boat stable enough"? I would
say, "Step on the gun'l and see." People would always
conclude, after this very real test, that our boat was just
as stable as 21 foot & 22 foot boats with lead ballasted
swing keels & keel/centerboards. It's a question of how the
boat is designed, not the material used for ballast.


The problem is that water in the ballast has the same density of the
water it is in

Well there you go again. The water ballast is not "in water"
it is in the boat.


Where is the boat?


Floating.

AGAIN-
If the water ballast did not "weigh anything" then the boat
would not get lower in the water when the ballast tank is
filled.


Let me propose this example- a cooler full of ice & beer is
lighter than water (hence lighter than water ballast) yet
can be pretty heavy when you're carrying it down the dock.
If you put it in the lowest possible location in the boat,
right down against the hull, and tie it in securely (to the
handles, so you can still open the lid of course), will this
improve the boat's stability?


What is your point?

That water ballast works just fine.


... I think you need to consider the
basics when considering a sailing vessel;

We have done exactly that, Dave.

.... water on or about the
centerline is a waste of potential that is even more easily achieved
otherwise.

Really? Like what?

.... It is the same density of the stuff you're moving through -
it's a very major factor, as you're floating on it.

Actually, it's not a factor at all. Water is heavy. Put it
down low in the boat, and it functions as ballast.


.... Consider the
obvious. When the boat is on an angle the only force the water can
exert is on the air below it and not the water (it exerts no effective
force on the water if you can get your head around that).

Wrong, wrong, and wrong.

Does the force of gravity have some sort of sixth sense that
the water ballast is "exerting force on the air below it"?

No, gravity pulls downward equally on the water ballast at
all times, just as it does on the hull, the crew, the beer,
and for that matter, the water that the boat is floating in.



Consider the absurd, a boat of no mass other than its water ballast. It
will sit in the water, level with the ballast waterline. If you are to
heel it - well you work it out. The maths is easy, consider the water
ballast as a "solid" (as it cannot move).

The ballast lowers the center of gravity of the boat. As the
boat heels, the center of bouyancy shifts to the low side.
The center of bouyancy pushes up, the center of gravity
pushes down, when the boat is level they are in alignment.
When the boat is heeled, there is a lever arm between the
forces which is the force we call "righting moment."

A given displacement & a given lever arm will give the same
righting moment, whether the ballast is lead or feathers. It
is true that lead can be placed lower in the boat, but that
doesn't change the basic physics of stability.





Short of moving magically moving the water ballast from one side to the
other - same as the tack - water ballast is a crock.


Wrong. Just look at the plain facts.

It's a lot heavier than air, but look at "what you're doing" and the
alternatives.

Come on - do my maths (example question posed already, no answers yet)


I have given you many sensible answers, and tried to explain
the physics in easy terms. I thought you were getting the
point, but no you reply that 'it's a crock.' So good bye, Dave.

Fresh Breezes- Doug King

Any thoughts onhow to make this boat better
 

In article ,
says...
.... You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?



Well?
How about an answer on this one?

It's in the jug. Where's the jug? What's the overall effect of the jug?


Let me propose this example- a cooler full of ice & beer is
lighter than water (hence lighter than water ballast) yet
can be pretty heavy when you're carrying it down the dock.
If you put it in the lowest possible location in the boat,
right down against the hull, and tie it in securely (to the
handles, so you can still open the lid of course), will this
improve the boat's stability?


Dave Doe wrote:
Not a lot no.

Which means yes.

Correct, never denied (2nd or 3rd or 4th time I've had to say that?).
The righting factor is almost purely *density* related though. Hint:
think about what you're 'in' and what you 'are' and what you 'have' to
provide righting moment.

Clearly - any material not exceeding the density of what you are 'in' is
going to be poor. Given 'ideal' (no mass boat) - it's extremely poor.
Add the mass of the boat itself, it's even worse performance wise.

Ah good, so now we've gone from "Water cannot be ballast
because it doesn't weigh anything when below the waterline"
to admitting that something that is in fact lighter than
water *can* function as ballast below the water line,
although not as efficently as denser material.

Sorry if you're a pedantic ******* :) - my argument simply asks to
compare the effectiveness of water ballast righting ability vs lead
keel. PS: I think you've misquoted me - indeed I think you have taken
the ol' poetic licence thingie and just made up my "quote" - if so, yer
a *******. If not, sorry, but water (or any mass) is a ballast that has
inertia (perhaps I've confused folk with stability when I mean momentum
or inertia) - however that does *not* go hand in hand with righting
ability. Again, sorry for any confusion there, I take 1/2
responsibility.

I've posted the comparison question. Send your answers to D. Conners.


Think it over some more. I compliment you on your ability to
gradually recognize facts contrary to your prejudices. Most
people can't ever take this first small step.

Hmmm, I think you're comment quite pretentious. How about we keep to
fact not fiction. My initial reply to the OP was stability in terms of
momentum or inertia (due mass) - and not stabilty in terms of righting
ability (due density). I hope that is clear.

--
Duncan

Any thoughts onhow to make this boat better
 

.... You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?



Dave Doe wrote:
It's in the jug. Where's the jug? What's the overall effect of the jug?

It is lower in the water because of its increased weight.
Hence, increased displacement.... it should be very obvious
that the water in the jug has weight.



Not a lot no.

Which means yes.


Correct, never denied (2nd or 3rd or 4th time I've had to say that?).

Like 2nd or 3rd or 4th time you've "had" to say that 'water
doesn't weigh anything in water.'


The righting factor is almost purely *density* related though.

No, it isn't.

It is related to weight (pushing down on mass) and bouyancy
(pushing up on volume).

... Hint:
think about what you're 'in' and what you 'are' and what you 'have' to
provide righting moment.


I am explaining exactly that. Density has nothing to do with
the basics of how stability is achieved.


Clearly - any material not exceeding the density of what you are 'in' is
going to be poor.

Wrong.



Sorry if you're a pedantic ******* :)

Trying to clear up your prejudices & misconceptions makes me
a pedantic *******?

Thanks.

DSK

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote in message
. nz...

You clearly have no idea what MASS and DENSITY are about.


Yes I do, I have a lot of MASS and you are DENSE.

SBV

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

Any thoughts onhow to make this boat better
 

Jax?




"Dave Doe" wrote in message
. nz...
In article ,
says...
Are you saying that the water ballast inside a boat hull
does not affect it's stability? That the water ballast
"weighs nothing" until it is above the waterline?


Dave Doe wrote:
Nope, never did. I'm saying it's stability is indeed
improved (more
mass to move)

That would be an issue of inertia... dynamic stability, if
you like the term.

ie stability.

... but question its righting ability vs lead keel - and
posed a question about that.


Well, I don't think that anybody has claimed that water
ballast provides equal righting moment to external lead
ballast. But it can provide significant righting moment,
especially if the boat is designed from the start to utilize
water ballast effectively.

Provide some evidence.

The problem is that water in the ballast has the same
density of the
water it is in

Well there you go again. The water ballast is not "in water"
it is in the boat.

Where is the boat?

Will no amount of repetition get this
point across? You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?

Let me propose this example- a cooler full of ice & beer is
lighter than water (hence lighter than water ballast) yet
can be pretty heavy when you're carrying it down the dock.
If you put it in the lowest possible location in the boat,
right down against the hull, and tie it in securely (to the
handles, so you can still open the lid of course), will this
improve the boat's stability?

What is your point? Put feathers in the bottom of your boat?
Or put
water? Or go deeper 1and put lead? I think you need to
consider the
basics when considering a sailing vessel; water on or about the
centerline is a waste of potential that is even more easily
achieved
otherwise. It is the same density of the stuff you're moving
through -
it's a very major factor, as you're floating on it. Consider
the
obvious. When the boat is on an angle the only force the water
can
exert is on the air below it and not the water (it exerts no
effective
force on the water if you can get your head around that). And
that is
only because it is held there in it's ballast tank and not
allowed to
'seek it's natural place at the bottom' (it's heavier than the
surrounding air - but please don't dissregard the whole
equation - what
the boat is in).

Consider the absurd, a boat of no mass other than its water
ballast. It
will sit in the water, level with the ballast waterline. If you
are to
heel it - well you work it out. The maths is easy, consider
the water
ballast as a "solid" (as it cannot move).

Then consider the same mass many times denser at a point well
beyond the
fulcrum point the water ballast is on.

Also think of boat speed and drag (wetted area).

Short of moving magically moving the water ballast from one
side to the
other - same as the tack - water ballast is a crock.

It's a lot heavier than air, but look at "what you're doing"
and the
alternatives.

Come on - do my maths (example question posed already, no
answers yet)

--
Duncan

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote in message
. nz...
In article ,
says...

"DSK" wrote in message
. ..

Well there you go again. The water ballast is not "in
water"
it is in the boat. Will no amount of repetition get this
point across? You used the example of an empty jug vs one
1/2 full of water... is the water in the jug "in water" or
is it in the jug?


Dave just doesn't get it.
And he refuses to do any experiments because he is afraid of
water.

Is the water in a plastic floating in the ocean:
a) in the plastic bag?
b) in the water?

Well technically, it's in the plastic bag. Is the plastic bag
a factor?
No.


So now plastic is weightless too? Oh, the fact that you can see
through it is fooling you.

Scotty

Any thoughts onhow to make this boat better
 

In theory, if you sealed your mast and filled it with helium,
would that decrease 'weight aloft'?

Help with stability?

SBV



"DSK" wrote in message
t...
.... You used the example of an empty jug vs one

Any thoughts onhow to make this boat better
 

In article ,
says...
Dave Doe wrote:
Nope, never did. I'm saying it's stability is indeed improved (more
mass to move)

That would be an issue of inertia... dynamic stability, if
you like the term.


Dave Doe wrote:
ie stability.


There is a difference between static stability ei righting
moment, and dynamic stability or roll resistance. The first
is relatively simple, the latter vastly complex and
influenced by underwater foils, distribution of mass,
distribution of hull volume & reserve bouyancy, etc etc.

Correct me if I'm wrong, Dave: you started out by saying
that water ballast cannot generate righting moment.

No I said it provides stability - which you have accurately identified
above as intertial/momnentum type stability vs righting moment.

Righting moment - for us yachties - is, to me, very questionable vs
traditional keel weighted systems.

This is a yachting NG not a ship NG. Performance is foremost. I've
posted a comparison question. And indeed continue to question the
effectiveness (or lack of) of water ballasted sailing vessels. As said:
what you are 'in', what you 'are, and what your 'ballast is' - are
"relatively" important in terms of *density*.

Here's a comparison in air:
To fly a plane two important calculations have to be done:
1. must be below MAUW (maximum all up weight). This equates to having a
boat that is denser than water - yer sink. (OK, not really, safety
margin involved but any folk that "know" can see by your takeoff if
you're overloaded - sticks out like a sore thumb).
2. must be within center of gravity limits (stated 'arms' for postions
on the plane: rear seats, front seats, wings (fuel), calc moments for
those based on masses in those positions, add 'em up - is it 'in the
envelope'?). In a *yacht* - the very opposite applies, the COG (or arm
or leverage point) needs to be as displaced as possible - this is
maxmised by mass/density and leverage (arm (distance "away")).

You have yet to convince me how a water ballasted yacht does a good job
of that given it fails on both counts: mass due density/volume and
leverage.

... but question its righting ability vs lead keel - and
posed a question about that.


Well, I don't think that anybody has claimed that water
ballast provides equal righting moment to external lead
ballast. But it can provide significant righting moment,
especially if the boat is designed from the start to utilize
water ballast effectively.


Provide some evidence.


That lots & lots of water ballast boats are out there
sailing? That I've personally sailed about a dozen boats
with water ballast, and found them to have no significant
difference in the way they sail compared to lead ballasted
boats?

For example, we owned & sailed a 19' water ballasted sloop
for eleven years. Many times at club get-togethers, people
would say "Is a water ballast boat stable enough"? I would
say, "Step on the gun'l and see." People would always
conclude, after this very real test, that our boat was just
as stable as 21 foot & 22 foot boats with lead ballasted
swing keels & keel/centerboards. It's a question of how the
boat is designed, not the material used for ballast.

It has everything to do with the ballast material - specifically the
density of. If the ballast was not at least the density of water, it
would not right if it was flooded with water, would it? Indeed it would
turn the boat upside down. Isn't that why poly and other 'lighter than
water' materials are put in at or near the topsides of boats - to keep
them upright and in some cases floating when "sunk"? (they are of
lesser density than water).

The problem is that water in the ballast has the same density of the
water it is in

Well there you go again. The water ballast is not "in water"
it is in the boat.


Where is the boat?


Floating.

In? Density of that stuff? Relativity is important here. Density of
water is 1000kg/m3 at STP. Consider any boat; it's volume, it's mass -
and therefore its density. *ANY* boat with a density less than
1000kg/m3 will therefore float (better be pedantically correct: fresh
water: STP). So long as the 'boat' has itself, a displaced center of
gravity (feathers as some would like) then it will have righting force -
albiet your sailboat, not mine. For yachting, that is a *very*
important factor. We're not just using righting force against a
possible capsize - we're sailing. So "maximise the righting moment" is
a designer's goal surely.


AGAIN-
If the water ballast did not "weigh anything" then the boat
would not get lower in the water when the ballast tank is
filled.

100kg of anything will displace 100liters of fresh water at STP - right.

Let me propose this example- a cooler full of ice & beer is
lighter than water (hence lighter than water ballast) yet
can be pretty heavy when you're carrying it down the dock.
If you put it in the lowest possible location in the boat,
right down against the hull, and tie it in securely (to the
handles, so you can still open the lid of course), will this
improve the boat's stability?


What is your point?

That water ballast works just fine.


... I think you need to consider the
basics when considering a sailing vessel;

We have done exactly that, Dave.

.... water on or about the
centerline is a waste of potential that is even more easily achieved
otherwise.

Really? Like what?

Everything denser than water. If as a keel, it will have less wetted
area and provide leverage. If 'in the boat' it will occupy less space
and so be closer to the centerline in terms of height and width however
it will provide little leverage (but still be better than anything less
dense in the same place).

.... It is the same density of the stuff you're moving through -
it's a very major factor, as you're floating on it.

Actually, it's not a factor at all. Water is heavy. Put it
down low in the boat, and it functions as ballast.

"Water is heavy" is a meaningless statement. Indeed in the perspective
it should be viewed: the boat, the ballast and the water - it's heavier
than much of the boat (it won't work otherwise).

Water is as heavy as it is - specifically 1000kg/m3 (I guess I need to
spell it out: fresh water, STP). So we have a density factor. That's
what we are floating IN.

You have admitted a lead keel is a lot better yerself. OK, yer comments
above re your water ballasted yachting days noted; digested and now laid
to rest in the most private room in the house - um... you sail in a
traditional lead type keel fined boat now?

You're racing tomorrow - it's gonna be close. You have a full holding
tank and water tank. Both lower GOG. Gonna leave 'em that way?


.... Consider the
obvious. When the boat is on an angle the only force the water can
exert is on the air below it and not the water (it exerts no effective
force on the water if you can get your head around that).

Wrong, wrong, and wrong.

Does the force of gravity have some sort of sixth sense that
the water ballast is "exerting force on the air below it"?

No, gravity pulls downward equally on the water ballast at
all times, just as it does on the hull, the crew, the beer,
and for that matter, the water that the boat is floating in.

Sorry for my rough physics - however my argument is - in essence the
same thing... do I need to explain? - I guess so... the air 'below' the
water is the air that is just that - below and to one side of the water
(the boat is say at 45 deg). Gravity will exert a greater force,
effectively, on one side of the boat, due the water being more on that
side, and the air more on the other. The effective force itself - will
be the "water on one side over the air on the other".

Consider the absurd, a boat of no mass other than its water ballast. It
will sit in the water, level with the ballast waterline. If you are to
heel it - well you work it out. The maths is easy, consider the water
ballast as a "solid" (as it cannot move).

The ballast lowers the center of gravity of the boat. As the
boat heels, the center of bouyancy shifts to the low side.
The center of bouyancy pushes up, the center of gravity
pushes down, when the boat is level they are in alignment.
When the boat is heeled, there is a lever arm between the
forces which is the force we call "righting moment."

A given displacement & a given lever arm will give the same
righting moment, whether the ballast is lead or feathers. It
is true that lead can be placed lower in the boat, but that
doesn't change the basic physics of stability.

I wouldn't agree with that at all. You correctly state COG - nice to
see you are getting it. Lead is heavier than water, it can therefore
increase righting moment: acting a) as a heavier and denser mass and b)
at beyond the centerline of the boat, greatly increasing leverage or
arm. Anything less dense will result in decreased arm if mass is held
constant. This applies to water ballasts.

Short of moving magically moving the water ballast from one side to the
other - same as the tack - water ballast is a crock.


Wrong. Just look at the plain facts.

It's a lot heavier than air, but look at "what you're doing" and the
alternatives.

Come on - do my maths (example question posed already, no answers yet)


I have given you many sensible answers, and tried to explain
the physics in easy terms. I thought you were getting the
point, but no you reply that 'it's a crock.' So good bye, Dave.

No probs, I've got my books nearly done - so won't be back to read
anymore crocks for another day - you're off the hook for 12 hours.


--
Duncan

Any thoughts onhow to make this boat better
 

In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.

--
Duncan

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.


Bzzzt...Oh, I'm sorry, the correct answer is ''WATER'' .

Thanks for playing.

SBV

Any thoughts onhow to make this boat better
 

Debra, your stupid. Thats the foulest boat to ever sail on water.

Only way you can improve that crapper is to sink it.

Why a fool would even look a cheap white trash boat like that is beyond
me.

Wooooo Hooooo.. Your a loser, most likey a water head, get a shunt
valve installed before it's to late!

RB
35s5 Nicer than nice
NY

Any thoughts onhow to make this boat better
 

Wooooo Hooooo.. Your a loser, most likey a water head, get a shunt
valve installed before it's to late!


Now if only this loser had my grace and charm...ah well. Some of you
ARE stupid so read the headers. This wannabe is posting from Yahoo.
Then again he could be right about the shunt valve part.


RB
35s5
NY

Any thoughts onhow to make this boat better
 

I think it's got you down pat Bobsprit.....

Grace & Charm????.... Bwahahahahahahahahahaahaaaaaa

CM

"Capt. Rob" wrote in message
oups.com...
Wooooo Hooooo.. Your a loser, most likey a water head, get a shunt
valve installed before it's to late!


Now if only this loser had my grace and charm...ah well. Some of you
ARE stupid so read the headers. This wannabe is posting from Yahoo.
Then again he could be right about the shunt valve part.


RB
35s5
NY

Any thoughts onhow to make this boat better
 

Dave,

I'm not sure if you're serious about this project, but if so, I suggest
you follow plans based on a boat that has been built and tested. I have
a water-ballasted boat, and there are several design factors unique to
these boats. - For example, how are you going to ensure that the
ballast tank doesn't deteriorate over time, leak, or break away from the
hull in rough seas? What's the shape and position of the tank in the
boat, and how are you going to fill and empty the tank? If it's a
sailboat, you will of course still need some sort of keel or dagger
board, etc.. - Are you going to extend it through the tank, or affix it
to the hull? If the latter, how are you going to attach it to the hull,
below the ballast tank? For added stability, our boat has about 400
pounds of fixed ballast in addition to the water ballast, which helps
keep the boat stable if the water ballast tank isn't filled. Another
option is to have tanks on both sides of the boat that can be filled
individually, which offers some advantages but would be pretty much of a
hassle to maintain and fill and empty the tanks when underway.

Jim


Dave Doe wrote:

In article .com,
says...


I have been getting interested in building this boat:
http://www.duckworksbbs.com/plans/jim/cormorant/
Of course, I have to finish the Tolman Skiff first, but a trailerable
water ballast sailboat that I can build to my needs is attractive to me
but I have some concerns
1. Do water ballasted boats tend to be exceptionally "tippy" before
they are filled?
2. Could this be alleviated by including a few hundred lbs of lead
sheeting along the bottom?
Any other useful thoughts? Yes, I know you do not save money by
building boats but its become an obsession.



I have a couple a questions...
1. How much water ballast (approx litres) does it take to equal say
200lbs of lead hanging 6' down (on say a swing keel)?

2. How much righting moment does a water ballasted boat provide given
the ballast is below the waterline?

And a cheeky Q3? - How much does water weigh - in water?

Any thoughts onhow to make this boat better
 

In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.


Bzzzt...Oh, I'm sorry, the correct answer is ''WATER'' .

Thanks for playing.

Water - ROTFL.

No, subs sink cos either they're heavier than water in the first place,
or they use ballast that is heavier than water such as: Lead, or for
modern wartime subs I would think they'd use DU (depleted uranium).

Water! - LOL.

So the correct answer is most assuredly not water. Subs are made so
that the mass/volume is denser than that of water - and they sink. They
then have *AIR* in them that provides bouyancy - the cool thing about
air is it's *compressability*. The "blow the (air) tanks" - and the
decrease in bouyancy means they sink. To surface, they blow the water
*out* of the air tanks, filling 'em with the air from the compressed air
source.

Think of a diver - FFS. They sink because of? Same as a sub - only as
said, I would think modern war subs use denser material such as DU -
'cos they can afford it.

So the correct answer is lead or DU.

--
Duncan

Any thoughts onhow to make this boat better
 

In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.


Bzzzt...Oh, I'm sorry, the correct answer is ''WATER'' .

Thanks for playing.

Water - ROTFL.

No, subs sink cos either they're heavier than water in the first place,
or they use ballast that is heavier than water such as: Lead, or for
modern wartime subs I would think they'd use DU (depleted uranium).

Water! - LOL.

So the correct answer is most assuredly not water. Subs are made so
that the mass/volume is denser than that of water - and they sink. They
then have *AIR* in them that provides bouyancy - the cool thing about
air is it's *compressability*. The "blow the (air) tanks" - and the
decrease in bouyancy means they sink. To surface, they blow the water
*out* of the air tanks, filling 'em with the air from the compressed air
source.

Think of a diver - FFS. They sink because of? Same as a sub - only as
said, I would think modern war subs use denser material such as DU -
'cos they can afford it.

So the correct answer is lead or DU.

--
Duncan

Any thoughts onhow to make this boat better
 

In article ,
says...
In theory, if you sealed your mast and filled it with helium,
would that decrease 'weight aloft'?

Help with stability?


Yes.

No, due to a lack of mass well beow the COG, infact a decrease in
stability.


--
Duncan

Any thoughts onhow to make this boat better
 

http://express.howstuffworks.com/express-submarine1.htm



How Submarines Sink & Swim
To dive underwater and then resurface, the submarine's crew must
be able to control the ship's weight or density. We can compare
this to an empty can floating in the water. The empty can could
become more "rock-like" and sink by pouring water into the can.
By controlling the amount of water we pour into the can, we can
control the rate and depth of its dive under the water's surface.


Submarines have an inner and an outer steel shell, called a hull.
The area in between the two hulls is called the ballast tank. It
can be filled with either air or water. When the submarine is on
the surface, the ballast tanks are filled with air and the
submarine's overall density is less than that of the surrounding
water.

Ballast tanks are open at the bottom. To dive, the submarine
operator opens up valves at the top and lets air out. It's
something like blowing bubbles when you are swimming underwater.
Seawater rushes in to fill the space that was taken up by air.
This changes the ship's density.

When the density of the submarine is greater than the surrounding
water, it begins to sink. This is called negative buoyancy. A
moveable set of wings, called hydroplanes, helps control the
angle of the dive.

To keep the submarine at any specific depth, the crew adjusts the
mixture of air and water in separate, smaller ballast tanks. The
operator tries to keep the submarine's overall density about the
same as the surrounding water. This is called neutral buoyancy.
When the submarine reaches its cruising depth, the hydroplanes
are straightened so the craft can travel level through the water.
If something changes the submarine's weight and density, such as
firing torpedoes, the operator must make further adjustments of
the water/air mixture in the ballast tanks.


"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can
you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.


Bzzzt...Oh, I'm sorry, the correct answer is ''WATER'' .

Thanks for playing.

Water - ROTFL.

No, subs sink cos either they're heavier than water in the
first place,
or they use ballast that is heavier than water such as: Lead,
or for
modern wartime subs I would think they'd use DU (depleted
uranium).

Water! - LOL.

So the correct answer is most assuredly not water. Subs are
made so
that the mass/volume is denser than that of water - and they
sink. They
then have *AIR* in them that provides bouyancy - the cool thing
about
air is it's *compressability*. The "blow the (air) tanks" -
and the
decrease in bouyancy means they sink. To surface, they blow
the water
*out* of the air tanks, filling 'em with the air from the
compressed air
source.

Think of a diver - FFS. They sink because of? Same as a sub -
only as
said, I would think modern war subs use denser material such as
DU -
'cos they can afford it.

So the correct answer is lead or DU.

--
Duncan

Any thoughts onhow to make this boat better
 

http://www.fleetsubmarine.com/diving.html


To submerge, the crew opens vents at the top of the ballast
tanks. This lets the air out. The bottom of the ballast tank is
open to the sea, so as soon as the air is released water comes in
to take its place, the displacement increases, and the boat slips
below the surface.

Submarines are designed so that, with the main ballast tanks
full, the weight of water they displace will be as close as
possible to exactly equal to the weight of the boat. In practice,
the boat should retain a slight amount of positive buoyancy, so
that it will want to slowly rise to the surface if nothing else
acts to keep it under.









"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can
you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.


Bzzzt...Oh, I'm sorry, the correct answer is ''WATER'' .

Thanks for playing.

Water - ROTFL.

No, subs sink cos either they're heavier than water in the
first place,
or they use ballast that is heavier than water such as: Lead,
or for
modern wartime subs I would think they'd use DU (depleted
uranium).

Water! - LOL.

So the correct answer is most assuredly not water. Subs are
made so
that the mass/volume is denser than that of water - and they
sink. They
then have *AIR* in them that provides bouyancy - the cool thing
about
air is it's *compressability*. The "blow the (air) tanks" -
and the
decrease in bouyancy means they sink. To surface, they blow
the water
*out* of the air tanks, filling 'em with the air from the
compressed air
source.

Think of a diver - FFS. They sink because of? Same as a sub -
only as
said, I would think modern war subs use denser material such as
DU -
'cos they can afford it.

So the correct answer is lead or DU.

--
Duncan

Any thoughts onhow to make this boat better
 

Dave Doe wrote:
In article ,
says...
In theory, if you sealed your mast and filled it with helium,
would that decrease 'weight aloft'?

Help with stability?


Yes.

No, due to a lack of mass well beow the COG, infact a decrease in
stability.

Your mast is below your boat's COG? Is the boat inverted?


--
Capt Scumbalino

Any thoughts onhow to make this boat better
 

In article ,
says...
Dave Doe wrote:
In article ,
says...
In theory, if you sealed your mast and filled it with helium,
would that decrease 'weight aloft'?

Help with stability?


Yes.

No, due to a lack of mass well beow the COG, infact a decrease in
stability.

Your mast is below your boat's COG? Is the boat inverted?

Comprehension probs?

Hopefully you've comprehended one thing though - the guy posted a really
dumb question.

--
Duncan

Any thoughts onhow to make this boat better
 

In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.


Bzzzt...Oh, I'm sorry, the correct answer is ''WATER'' .

Thanks for playing.

Thanks for your worthless (top posted) posts and links re subs. They
point out what I have already - that subs sink because their overall
density is greater than that of the water they are in.

They DO NOT SINK BECAUSE OF WATER!!! - and none of those articles you
posted suggest they do. They simply describe the bouyancy mechanism
subs use to go up or down in the water.

Like I also suggested to you - why don't you try thinking of something
simpler - such as a diver.

Even a simpleton like you should be able to work out that, just like a
sub, a diver has a bouyancy device - the BCD. However it is of no use,
no matter how much air you drain from it, or replace with water - if the
diver is not wearing their weight belt.

Thanks for the laughs though.

--
Duncan

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote


Hopefully you've comprehended one thing though - the guy posted
a really
dumb question.

there are no dumb questions, only dumb answers posted by dumb
persons.

Scotty

Any thoughts onhow to make this boat better
 

Dave, stop trying to change your statements (and stop bottom
posting).
You stated that subs don't use water for ballast.
I posted a few, out of many, sites that state otherwise.



--
Scott Vernon
Plowville Pa _/)__/)_/)_



"Dave Doe" wrote in message
z...
In article ,
says...

"Dave Doe" wrote in message
. nz...
In article ,
says...

"Dave Doe" wrote in message
. nz...

Can you sink a 'positive buoyancy' boat with water? Can
you
sink it with
lead? You've proven my own point.



What do submarines fill their ballast tanks with?

positive bouyancy boat submarine - EVER.


Bzzzt...Oh, I'm sorry, the correct answer is ''WATER'' .

Thanks for playing.

Thanks for your worthless (top posted) posts and links re subs.
They
point out what I have already - that subs sink because their
overall
density is greater than that of the water they are in.

They DO NOT SINK BECAUSE OF WATER!!! - and none of those
articles you
posted suggest they do. They simply describe the bouyancy
mechanism
subs use to go up or down in the water.

Like I also suggested to you - why don't you try thinking of
something
simpler - such as a diver.

Even a simpleton like you should be able to work out that, just
like a
sub, a diver has a bouyancy device - the BCD. However it is of
no use,
no matter how much air you drain from it, or replace with
water - if the
diver is not wearing their weight belt.

Thanks for the laughs though.

--
Duncan

Any thoughts onhow to make this boat better
 

In article ,
says...
Dave, stop trying to change your statements (and stop bottom
posting).
You stated that subs don't use water for ballast.
I posted a few, out of many, sites that state otherwise.

a.
Indeed they do not. They probably use Lead or DU. Neither of those
sites w' the info you posted conclude that subs use water for ballast -
one mentions the key fact, a sub is denser than water. The bouyancy
ballast tanks are then regulated with air to adjust density and float or
sink as required. The water in the bouyancy ballast tanks serve only to
displace the air - and it's ideal as it has the same density as the
water the sub is in (and that alone should tell you, it can never make
the sub sink!)

b.
You are referring to the bouyancy ballast tanks - diphead! That is
*not* "the ballast". Equivalent to a diver's BCD.

c.
Without the ballast at the bottom of a sub (as said, I believe it will
be Lead (or DU for modern war subs)), OR the construction itself -
producing a vessel that is denser than water (mass/volume) - the sub
will not sink!

Just like a diver without a weight belt.

And PS: the only reason subs replace the air with water in the bouyancy
ballast tanks is because they are solid tanks - the water is irrelevant.
(A diver's BCD is not replaced with water, as it's a rubber bag that
simply deflates).

--
Duncan

Any thoughts onhow to make this boat better
 

You stated that subs don't use water for ballast.
I posted a few, out of many, sites that state otherwise.


Dave Doe wrote:
a.
Indeed they do not. They probably use Lead or DU.

Really? Is there a special place in the ocean where
submarines can just scoop up some lead or DU when they want
to dive?

DSK

Any thoughts onhow to make this boat better
 

In article ,
says...
You stated that subs don't use water for ballast.
I posted a few, out of many, sites that state otherwise.


Dave Doe wrote:
a.
Indeed they do not. They probably use Lead or DU.

Really? Is there a special place in the ocean where
submarines can just scoop up some lead or DU when they want
to dive?

You're just being a pedant aren't you.

What makes a diver sink? - the BCD? Or the weight belt?

The lead or DU is put in the sub at manufacture time, to ensure it is
"heavier than water" (it's overall desnity is greater than water).

Otherwise.. yes they *would* have to find a special place to scoop up
lead, DU, rocks - whatever - to submerge - as their bouyancy ballast
tanks would be ineffective with water in them. You'd have a positive
bouyancy vessel. You can put as much water in 'em as you like - it'd
never sink.

Ostentatious reply expected...

--
Duncan

Any thoughts onhow to make this boat better
 

Dave Doe wrote:
You're just being a pedant aren't you.


No, I am less interested in seeming clever, and playing
semantic games, than I am with simple facts and the physics
that make things work.

What makes a diver sink? - the BCD? Or the weight belt?


Totally different picture. The BCD is a variable volume
device. When the diver inflates it, he is increasing his
displaced volume. That would be similar to attaching a
helium balloon to a sailboat mast for added stability.


The lead or DU is put in the sub at manufacture time, to ensure it is
"heavier than water" (it's overall desnity is greater than water).


Then why does it float when the diving ballast tanks are empty?

Otherwise.. yes they *would* have to find a special place to scoop up
lead, DU, rocks - whatever - to submerge - as their bouyancy ballast
tanks would be ineffective with water in them. You'd have a positive
bouyancy vessel. You can put as much water in 'em as you like - it'd
never sink.


Really? The fact that they're made of steel, and are
ostentatiously lacking in styrofoam, would make it seem
likely otherwise.

Fact- water ballast works just fine.

Fact- any physics used to try & pretend it doesn't must be
false... just like any physics explaining why airplanes
can't really fly... or is that going to be your next hobby?

I do have one suggestion for you.... look up 'metacentric
height' and ponder the relationship of the ceneter of
gravity to the center of bouyancy. It's easier than the
sound of one hand clapping.

DSK

Any thoughts onhow to make this boat better
 

"DSK" wrote in message
...
You stated that subs don't use water for ballast.
I posted a few, out of many, sites that state otherwise.


Dave Doe wrote:
a.
Indeed they do not. They probably use Lead or DU.

Really? Is there a special place in the ocean where
submarines can just scoop up some lead or DU when they want
to dive?


yes, in Doe Doe land.

SV

Any thoughts onhow to make this boat better
 

"Dave Doe" wrote in message a.


b.
You are referring to the bouyancy ballast tanks - diphead!
That is
*not* "the ballast". Equivalent to a diver's BCD.


diphead? My my, getting a bit testy, are we?



c.
Without the ballast at the bottom of a sub (as said, I believe
it will
be Lead (or DU for modern war subs)), OR the construction
itself -
producing a vessel that is denser than water (mass/volume) -
the sub
will not sink!


Oh, right, I keep forgetting, water weighs zero in Doe Doe land.

SV