"Wayne.B" wrote in message
...
On Tue, 6 Jan 2004 19:24:30 -0500, "Gary Warner"
wrote:
I've had a few random questions rattling around the
brain for a while - figured I'd pose them there.

When a sub dives to a certain depth, is that depth
measured from the bottom of the sub, the middle,
or the top. In other words, if it dives to 200 feet,
does that mean there is 200 feet of water above
it or that the bottom of it is 200 feet below the
surface?

Interesting question but I have no idea.

On modern gas car engines and when it's cold
outside, is it still better to let them warm up a
bit and how warm (how long) is necessary?

Not necessary at all assuming everthing is in tune and the engine is
running smoothly. Just don't over rev the engine until it's up to
operating temperature, usually within a few miles.

Anyone have a good way to find the total surface
area of my boat hull while it's in the water? It's
a 22' boat, not very deep V, "square" transom. I
did some estimating, but wonder if there are any
creative ways to get more accurate.

If you piece it out into a rectangle and a triangle on each side, you
can get pretty close with a deep V hull. Given the deadrise angle and
length we could develop a trig formula that would be a good
approximation, but it's easier to piece it out, and you'll have a
better intuitive sense of the answer. (Length x Beam) + a small fudge
factor will also get you pretty close.

When the boat is in the water, draw a line on the side a short distance
above the water line, say 1 inch, with a grease pencil or sharpie
marker. Then when the boat is out, use a 1 foot square of cardboard and
trace around it to make a grid from the keel to the waterline. Only
have to do half the boat, and so only will have maybe 50 or 60 squares.
you could make smaller rectangles or triangles to fill in gaps if you
are going for ultimate accuracy.

Suggestion 2. Instead of the squares, cut black plastic and tape to
exactly cover wetted surface. Weigh on accurate scale. Weigh a known
area. divide.

del cecchi

"del cecchi" wrote

Ahhh yes, there are the creative ideas I was thinking
must be out there.

Thanks to everyone that responded to these questions.

"Gary Warner" wrote in message
...
I've had a few random questions rattling around the

brain for a while - figured I'd pose them there.



When a sub dives to a certain depth, is that depth

measured from the bottom of the sub, the middle,

or the top. In other words, if it dives to 200 feet,

does that mean there is 200 feet of water above

it or that the bottom of it is 200 feet below the

surface?


8 years on submarines and it is bottom of keel. Most
subs read about 65 feet at periscope depth which has
the sail about 5 to 10 feet below the surface.



On modern gas car engines and when it's cold

outside, is it still better to let them warm up a

bit and how warm (how long) is necessary?

Not an expert but, cold starts are a major
cause of engine wear. The oil is too thick to get
through all the passages quickly. Yes, let it warm
at least a little before raising rpm's to drive.





Anyone have a good way to find the total surface

area of my boat hull while it's in the water? It's

a 22' boat, not very deep V, "square" transom. I

did some estimating, but wonder if there are any

creative ways to get more accurate.

No idea!!

8 years on submarines and it is bottom of keel. Most
subs read about 65 feet at periscope depth which has
the sail about 5 to 10 feet below the surface.

Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

On 07 Jan 2004 02:52:36 GMT, (Gould 0738) wrote:

8 years on submarines and it is bottom of keel. Most
subs read about 65 feet at periscope depth which has
the sail about 5 to 10 feet below the surface.

Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

That would depend on how far it surfaced. Did it blow all ballast or is
it just barely surfaced?

Steve

Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

That would depend on how far it surfaced. Did it blow all ballast or is
it just barely surfaced?

Steve


It can't blow enough ballast to put the keel on the surface. My point is merely
that if the depth is measured between the surface and the keel, (and I have no
reason to doubt that it is) there could never be a "zero" reading.

On 07 Jan 2004 08:04:48 GMT, (Gould 0738) wrote:

Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

That would depend on how far it surfaced. Did it blow all ballast or is
it just barely surfaced?

Steve


It can't blow enough ballast to put the keel on the surface. My point is merely
that if the depth is measured between the surface and the keel, (and I have no
reason to doubt that it is) there could never be a "zero" reading.

Think about it - "zero" is the bottom of the boat. If your boat draws
18 inches of water, then your keel is 18 inches below the surface and
thus that is "zero".

Zero is a fictional number anyway and can mean anything.

Later,

Tom
S. Woodstock, CT
----------
"My rod and my reel - they comfort me."

St. Pete, 12 Lb. Test

"Gould 0738" wrote in message
...
Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

That would depend on how far it surfaced. Did it blow all ballast or is
it just barely surfaced?

Steve


It can't blow enough ballast to put the keel on the surface. My point is
merely
that if the depth is measured between the surface and the keel, (and I
have no
reason to doubt that it is) there could never be a "zero" reading.

There is never a "Zero" reading, when on the surface it
is mid to high 30's depending on the type of sub. Also
for safety sake we never surface a little bit, when we
surface all ballast is blown.

Terry

On 07 Jan 2004 08:04:48 GMT, (Gould 0738) wrote:

Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

That would depend on how far it surfaced. Did it blow all ballast or is
it just barely surfaced?

Steve

If you do an emergency blow from test depth, the forward third of the boat will
come completely out of the water when the boat reaches the surface. For those
few seconds I think that would be a 'zero' reading.

JJ


It can't blow enough ballast to put the keel on the surface. My point is merely
that if the depth is measured between the surface and the keel, (and I have no
reason to doubt that it is) there could never be a "zero" reading.

James Johnson
remove the "dot" from after sail in email address to reply

On 07 Jan 2004 02:52:36 GMT, (Gould 0738) wrote:

Fascinating. What does the depth indicator say when the sub is surfaced?
Obviously it would not be zero.

We used to see subs on the surface all the time in eastern Long Island
Sound (sub base at Groton, CT). Only the conning tower and maybe 6
to 8 feet of hull is exposed at most when they are surfaced.
Estimating that the conning tower is submerged by 10 feet at periscope
depth, the height of the tower at 20 feet, plus 8 feet of hull - that
would put you about 38 feet above the periscope depth reading.

If you motor up the Thames River from New London, CT, you can actually
see partially assembled cross sections of subs on dry land. They look
incredibly big, even from a distance. And you really don't want to
take a lot of pictures or try to get closer. :-)