Encounters of the Submarine Kind

[sailpower]

Originally Posted by Victory 28

I was walking down the beach in Hobe Sound towards the preserve on the north end when I encountered a completely naked lady who was very, very beautiful. Not one to gawk, my eyes were completely fixated on her lovely form and right then the same fully grown man whom I had been observing prior to reaching this point in my walk, once again came running past this particular stretch of beach flying his kite, the actual direction of the breeze didn't seem to matter much to him, (typically useful for getting a kite aloft) he just kept running past about 60 or so yards then turning around and running back, unlike myself he never even glanced at her as far as I could tell though he was obviously very enthusiastic about flying his kite repeatedly past this particular spot. I gave her a surprised look after his 4th U-turn and we shared a smile and a laugh. I began to move in for a possible chat when right then a fast attack submarine surfaced in what could not have possibly been more than 40' of water, the periscope was steadfastly pointed in one direction. Meanwhile the amazing Mr. Kite had completed his southerly orbit and was pounding his way back. OK I thought this is just too much and I continued on my way feeling just a little happier.

If the depth was 40' it wouldn't have been underwater. The sub is taller than that.

US Submarines are restricted from diving in less than 100 fathoms.

I spent seven years in the USN submarine navy.

[senormechanico]

I seriously doubt there are any US subs in service that are diesel electric powered. Nowadays, they're all nuclear.
The nukes started around the "580" hull number.
The last diesel electrics I saw were when I was in the Navy submarine service the late '60's.
I was crew on this boat, the USS Pickerel ss524 thankfully not on this day though !
That was a test for an emergency surface from maximum depth.

[Cheechako]

Originally Posted by sailpower

If the depth was 40' it wouldn't have been underwater. The sub is taller than that.

US Submarines are restricted from diving in less than 100 fathoms.

I spent seven years in the USN submarine navy.

uhhh... I think you may have missed the joke!

[ZULU40]

Originally Posted by Seaworthy Lass

Thanks for the ID. At the time we were sailing between Greek islands, but in doing so had briefly cut into Turkish waters.

Wikipedia link to the Type 209 (designed in the 1960's):
https://en.m.wikipedia.org/wiki/Type_209_submarine

According to the above link they are still used by both the Turkish and Greek navies.

Note:
"They are powered by four MTU diesels and four AEG generators. The AEG electric motor is attached directly to a five- or seven-bladed propeller."

I can't imagine they are silent when running generators to charge their batteries.

If he is going home and his battery charge is good he might not feel the need to run the diesels up. Ive seen our own Type 471's on the surface purely under battery power usually as a part of float charge of their battery management.

Diesel electric boats journey quite a bit on the surface, but it is less comfortable and less efficient than submerged, and obviously compromises a missions integrity.

[ZULU40]

Originally Posted by senormechanico

I seriously doubt there are any US subs in service that are diesel electric powered. Nowadays, they're all nuclear.
The nukes started around the "580" hull number.
The last diesel electrics I saw were when I was in the Navy submarine service the late '60's.
I was crew on this boat, the USS Pickerel ss524 thankfully not on this day though !
That was a test for an emergency surface from maximum depth.

Ive been 'out' for some time now, my understanding is the USN had one Diesel electric for research purposes
Id contest that the nuke powered subs are better for every role. Well engineered DE boats are ultimately quieter, and make the best anti-sub platforms

[sailpower]

Originally Posted by Cheechako

uhhh... I think you may have missed the joke!

[Sailshabby]

I spent more than a few years on subs ('boats' as we called them). Prior to surfacing the girls in Sonar would do a surface check, then the Officer of the Deck would do a sweep on the 'scope. Generally enough (the tragedy in HI not withstanding) and we generally gave skimmers room. Years later I was sailing down from New England when one popped up a few hundred yards away and I was on the radio quickly. Naturally, no response, buying had to smile.

[sailpower]

Originally Posted by senormechanico

I seriously doubt there are any US subs in service that are diesel electric powered. Nowadays, they're all nuclear.

The nukes started around the "580" hull number.

USS Nautilus SSN-571

[ZULU40]

Originally Posted by kish

In 1997 I sailed on a yacht through a submarine exercise area off of North West Scotland and was hailed by a British warship, 12 miles to the east, and requested to alter course.
It was early evening with no engine running, sailing in a force 6 wind.
Some 10 minutes later we were subject to a mighty low pitched rhythmic acoustic noise loud enough to disturb the crew below deck. This lasted about 2 minutes.
It was not the doorbell style "ping" shown in submarine movies, but a mighty high decibel level, cabinet rattling base sound.
There was nothing visible on the surface and no further communication with the warship.

Those were the facts and here is my interpretation:
Presumably we were being "pinged" by a submarine.
Scary. as trawlers in the western Scottish and Irish Sea areas have been sunk by being towed backwards and foundering.
It is well known that submarines use the noise of shipping to hide from pursuers by steaming underneath the surface ship and it's acoustic shadow.
A 12 metre yacht with no machinery operating, and correspondingly quiet, would present an ideal exercise opportunity to a submarine and a sonar blast will locate it.
A steel hulled ship would not feel the sub's sonar used to position itself underneath as a yacht would.

thats active detection, used in circumstances when passive devices are bound to be less effective, such as high speed.

With subs its all about the boats ability to emit a similar noise signature to the ambient noise of the sea around it. It is possible to manipulate your noise to that of the surrounds, cloaked in this invisibility you are undetectable by passive detectors.

Any warship using active detecting would be an immediate target, and might not be able to hold onto the sub anyway. The faster she goes the less effective any method is, it isnt a game for anyone with uneasy nerves.

there is a video with somewhat of an inkling as to what happens, you might enjoy the technology aboard HMAS Rankine

https://www.youtube.com/watch?v=nqFVOL7mLd4

[senormechanico]

Originally Posted by sailpower

USS Nautilus SSN-571

I stand corrected.
I knew Nautilus was first, but the ones I saw around in Pearl Sub Base were all in the 580's.

Here's an example of the ones we routinely see in Admiralty when we're out on a daysail.

[sailpower]

Originally Posted by senormechanico

I stand corrected.
I knew Nautilus was first, but the ones I saw around in Pearl Sub Base were all in the 580's.

Here's an example of the ones we routinely see in Admiralty when we're out on a daysail.

Virginia class?

[skipmac]

Originally Posted by ZULU40

Ive been 'out' for some time now, my understanding is the USN had one Diesel electric for research purposes
Id contest that the nuke powered subs are better for every role. Well engineered DE boats are ultimately quieter, and make the best anti-sub platforms

I have read a number of articles about the latest generation of DE subs. From my very limited knowledge it sounds like, while under electric power, they are much quieter that nuclear. No pumps, cooling systems, valves and such to deal with. Of course they don't have the range and speed of nuclear but sounds like they would be excellent for anti-sub and super stealth roles.

[s/v Beth]

I am glad all you submariners joined the conversation. Can I ask you- does it make any difference to keep your depth sounder on? Would you recommend it in open ocean? I am willing to change if it is safer...

Originally Posted by ZULU40 View Post
Ive been 'out' for some time now, my understanding is the USN had one Diesel electric for research purposes

BTW I think this is the boat:
http://sdmaritime.org/visit/the-ship...hin-submarine/ She is a DE that held all types of records in her "research" purpose. You can tour her in San Diego.

[hsi88]

Wikipedia link to the Type 209 (designed in the 1960's):
https://en.m.wikipedia.org/wiki/Type_209_submarine

These folks have made over 100 subs for secondary navies. Why do I not feel safer knowing there are hundreds of subs operating outside of the major powers. I'm shocked there have not been more incidents (of any kind). Learn something new every day!

[ZULU40]

Originally Posted by skipmac

I have read a number of articles about the latest generation of DE subs. From my very limited knowledge it sounds like, while under electric power, they are much quieter that nuclear. No pumps, cooling systems, valves and such to deal with. Of course they don't have the range and speed of nuclear but sounds like they would be excellent for anti-sub and super stealth roles.

the USN have also leased a Kockums Gotland for evaluation, a smaller forerunner to the Type 471 Australia operate, which are the largest DE boats in the world. USN also extensively examined the 471 early in its tenure, but we were still fighting some formidable problems with the build at that time. So far the Kockums products have been the only boats to penetrate USN screens on tactical exercises.

Adherant to further devlopment are non air breathing stirling heat engines and battery technology to both extend range and increase speed. There is a statistic known as the dash speed, which indicates the maximum speed a boat can attain if depleating its entire battery in one hour. I cant say what the speed of 471 is without being arrested, perhaps I can indicate the commercial run of boats in this class expects to see 30 knots or so.

With just changing the batteries from existing Varta cell 2.2 volt lead acid battery (which stand about man high), to now old but familiar technology NiCd, pound for pound the power increase is a factor of around 2.4
From a basic engineering principle where 8x the power = 2x speed (its a cube root law) a NiCd battery should enable a 40+ knot dash speed, meaning she could outrun many if not all of the surface vessels pursuing her. And lets not forget battery tech has moved some way since NiCd's were developed