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

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

"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

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

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

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

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

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

"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

"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