In at the deep end!

#1
Hi Guys, My naval career was short and in the (beg pardon) the FAA. However, step son considers that I am the fount of all nautical knowledge. Here is his question, don't ask why he wants to know because he hasn't said!
"Could early WWII submerged submarines gauge the depth of the sea they were in passively ie without the use of sonar or other technology which would betray their position to surface vessels?" I think he was asking about the depth below the boat, not the depth from the surface as I assume that pressure gauges would give that info anyway.

I have been on either one or two Submarines, but both were alongside and definately not submerged. I can see that a guy standing on the bow with a line is out of the question (because I am fairly bright!) but I don't know how to answer him.

Having been lurking for more than a few weeks, I do expect a variety of answers from fellow members. (be kind)

I will appreciate any help.
Mugfaker.
 
#2
Welcome Mug...... what a CRACKING first post! I have absolutely no idea and to be honest had never even considered it before. It is possible that they just stuck to well charted areas where there was ample water known (hoped!) to be below them.

Is the lad in Mensa?
 

pie.thatcher

Lantern Swinger
#3
In my day in boats (60's 70's ) they always seemed to work from charts and dead reckoning. Close inshore echo sounders were used but they would certainly give your position away. Could be that by now they have some super duper system that doesn't rely on transmiting. Greater and younger minds than me might know.
 
#4
I left in 2007 and it's still echo sounders inshore but much improved from early days, other wise it's still chart work, or WECDIS (electronic charts). Doesn't mean you always get it right, as we found out on Traf when someone moved Fladda Chuain and we left the bow array as the first instalment of an independent Scotlands SOSUS.
 
#6
Logic would dictate, chart and good old dead reckoning. (Navigation to the un-initiated!!) Sonar was in it's infancy in WW2 so the use of passive is simply a non starter and actively 'pinging' well just send a text saying here I am!!!!!

I would say WW2 submarine skippers earned their salary in them that days!
 
#8
Logic would dictate, chart and good old dead reckoning. (Navigation to the un-initiated!!) Sonar was in it's infancy in WW2 so the use of passive is simply a non starter and actively 'pinging' well just send a text saying here I am!!!!!

I would say WW2 submarine skippers earned their salary in them that days!
I think that's basically the response I gave.
 
#10
Good afternoon,

It was my question that I put to my stepdad. The question came about from a Submarine simulation game called Silent Hunter 5, my older brother (52) was getting frustrated by not knowing the sea depth in the English channel. He would attempt to travel this route submerged and be detected by the pride of the British fleet. He would then emergency dive and and hit the sea bed. complaining that there was no way of knowing the depth beneath his hull and it was a stupid game. My response to him was often to say, do as I do and go round the north of Scotland, the route may be longer but safer. Apart from going past Scapa Flow, best done submerged at night if possible. It was my thought that back in 1939-1945 the only way of knowing depth of the sea currently in would from ocean charts? As anything else might reveal your position to the enemy (in this case the formidable British fleet).

Many thanks

Rik (aged 42 & a bit)
 
#11
To be honest I don't know of any Navy that sends boats on a dived transit of the Channel, far too shallow and busy. Before the fall of France U-boats used to take the long way round and would never risk the Channel. now I've said that someone's bound to come on and say "we did it in 19** on HMs/m ******" but I bet they didn't do it in the Dover Straits!
 
#15
We only bothered with echo sounders while at harbour stations, the remainder of the time, as has already been suggested, we chose to believe the admiralty charts for the depth of water under the keel. I would suggest that a short burst on the sounder was unlikely to give a boats location away in WW2 as the quality of the sonars in those time was nowhere near as good as at present and even if they heard it deciding from which direction would have been very tricky.
 
#17
Charts have been pretty accurate for some years, you would have no electronic nav aids on first world war battleships and they seemed to turn up at the right place as did Nelson 100 years earlier. I always got by before GPS but did have echo sounder and radar.
 
#18
Charts have been pretty accurate for some years, you would have no electronic nav aids on first world war battleships and they seemed to turn up at the right place as did Nelson 100 years earlier. I always got by before GPS but did have echo sounder and radar.
One word - ASTUTE!
 

janner

MIA
Book Reviewer
#19
Charts have been pretty accurate for some years, you would have no electronic nav aids on first world war battleships and they seemed to turn up at the right place as did Nelson 100 years earlier. I always got by before GPS but did have echo sounder and radar.
How did you measure depth under the keel with Radar?
 

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