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?



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?



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.



Gary

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?



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?



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.



Gary


Gary, I can tell you only that the surface area of your boat is the
same both in and out of the water.

John H

On the 'Poco Loco' out of Deale, MD
on the beautiful Chesapeake Bay!

Gary Warner wrote:


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?

Normally "depth to keel."


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?

RTFM

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.

Assuming you are seeking the "wetted area" rent one of those laser
thingys that scan a surface into a computer. Turn your boat on its side
and scan. Read computer generated results.

Rick

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?

Normally "depth to keel.

I don't know squat diddly about submarines, but I think I can answer this
question. *If* the dive indicator reads "zero" when the sub is on the surface,
the submerged depth would be measured from the normally ballasted waterline to
the surface. It wouldn't seem logical, otherwise.

On 07 Jan 2004 02:04:19 GMT, (Gould 0738) wrote:

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?

Normally "depth to keel.

I don't know squat diddly about submarines, but I think I can answer this
question. *If* the dive indicator reads "zero" when the sub is on the surface,
the submerged depth would be measured from the normally ballasted waterline to
the surface. It wouldn't seem logical, otherwise.

You want to read depth to keel because you want it to be consistent with
the depth markings on charts. If the depth was to anywhere else, you'd
have to figure that in and it can contribute to mistakes that might
cause a grounding. I.e., if you're in an area where the min charted
depth is 250 feet, you can order a 200 foot depth safely. If it was
measured to the top and you ordered a 200 foot depth in 250 feet of
water, you'd hit the bottom.

Steve

Gould 0738 wrote:

It wouldn't seem logical, otherwise.

Posting an answer to something I know nothing about is illogical.

Rick

Posting an answer to something I know nothing about is illogical.

Rick

I don't dispute that- ergo the disclaimer.
But if the depth is measured from the keel and there is a depth indicator on
the sub it will never read zero. Is that somehow incorrect? That was why I
postulated *if* a depth guage read zero at the surface the reading would have
to be from the normally ballasted waterline. Since it apparently does not read
zero, that theory doesn't fly. Freely admitted.

Gould 0738 wrote:

I don't dispute that- ergo the disclaimer.
But if the depth is measured from the keel and there is a depth indicator on
the sub it will never read zero. Is that somehow incorrect? That was why I
postulated *if* a depth guage read zero at the surface the reading would have
to be from the normally ballasted waterline. Since it apparently does not read
zero, that theory doesn't fly. Freely admitted.

It has never been part of submarine law that it must read zero on the
surface. Why should it?

The depth to keel is also an indication of freeboard. A submarine, after
surfacing, will use a low pressure blower to push the last bit of water
from the ballast tanks in order to increase the freeboard. The depth
gauge shows when it is as high as it will go.

Rick

"Rick" wrote:


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?

RTFM

I read the f'ing manual. It explains how
to start it in the cold but not a word
about warming it up or idling.

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.