Where do subs measure depth from?

[SparkySFD]

Small clarification from an ex Submarine Quartermaster.

Everything gkwaldee posted was correct.

Typically we use a fathometer while on the surface running to the dive point. As we are making noise anyway. However once submerged if the depth allows the fathometer is "secured".

Since a fathometer works by sending out an "active ping" it is only used according to regulations. Typically the maneuvering watch or in shallow water. Never when actually on an op.

There are actually quite a few dangerous places (shallow) in the open ocean. The caribbean comes to mind.


Doppler

My voice is actually in "The Hunt for Red October". All the sound effects were recorded on my boat. I actually had to baby sit a guy, who ran around with a pair of fuzzy microphones recording sounds all day. We ran a mock battlestations drill and many of our voices are in the scene towards the end of the movie. Right before the Dallas takes out the alpha. You can hear the Navigator as clear as day. I stood clear up in the theater when I heard it, HEY THATS MR. DOYLE! My girlfriend was pulling me down in embarassment. I only got two words in and you can barely hear it.

 

[The Kraken]

The depth is measured "from" the surface "to" the bottom of the keel.

 

[SparkySFD]

A "Depth Gauge" measures depth from the surface to the bottom of the keel (typically the lowest point of the boat).

A Fathometer measures the distance from the keel (where the hydrophone is) to the bottom of the ocean.

I just reread gkwaldee's last post.

"And normally we dont want to hit the bottom, especially when its 12,000 feet down!!"

You were long since dead before you got anywhere near 12,000 ft. So hitting the bottom at that depth wouldnt matter. Can you say "Exceeding crush depth boys and girls."

 

[wstein]

You were long since dead before you got anywhere near 12,000 ft. So hitting the bottom at that depth wouldnt matter. Can you say "Exceeding crush depth boys and girls."

My dad was subs way back in the day, and those were some words he said no submariner ever wanted to hear.

Paul

 

[gkwaldee]

A "Depth Gauge" measures depth from the surface to the bottom of the keel (typically the lowest point of the boat).

A Fathometer measures the distance from the keel (where the hydrophone is) to the bottom of the ocean.

I just reread gkwaldee's last post.

"And normally we dont want to hit the bottom, especially when its 12,000 feet down!!"

You were long since dead before you got anywhere near 12,000 ft. So hitting the bottom at that depth wouldnt matter. Can you say "Exceeding crush depth boys and girls."

Im doin USS SAN FRANCISCO homeported on Guam......and the water is VERY deep here, but id burn before wed ever get close to the bottom.

P.S.- did you know that the Navy finally got it right and did away with the QM rating? Yup, theyre all NAVET's now, and rightfully so!! Especially since computers, erasers are getting hard to find on a boat.

PSS- how long you been out? We just got the SEIE install.....let me tell ya about that contraption.

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