"False contacts by modern subs" Topic

For the Conn Sonar rules, I am writing up some rules about decoys and false contacts. As they stand, the rules require you to have 3 contacts on a target in order to acquire a firing situation.

To try to minimise the effect of the all-seeing eye, I will be having a number of decoy markers on the table and it will be perhaps with 2 contacts that it will be identified as a sub and potential target. The false contacts could include the like of marine fauna. My very vague question is "how noisy is the sea at sub operating depth" and how likely is it to encounter whales/squid/etc which could give arise to a false contact and how many false contacts might there be for every true contact?

From what I've read of the sub hunting during the Falklands Campaign, most contacts were false ones.

Lots of whales died to help keep the RN fleet safe from the sole Argentine sub on patrol there.

Lots of other stuff too, e.g. schools of fish, krill, giant squid, groups of smaller squid, etc., etc..

If I had to venture a guess, I'd say at least 10:1 false contacts, and probably, more likely, 20:1.

That doesn't even include all the rocks, and shipwrecks on the bottom too, when searching for a grounded sub.

The Argentine sub got away, despite numerous ships, subs, and helos searching for it, in challenging conditions, close to the islands.

Once upon a time, I created a nice D20 chart, for the above, just for grins, to keep RN and other escort vessel captains occupied with lots of false targets. Getting lulled into complacency by stuff like that should make for fun gaming too, at least for the submarine captains.

Not all at once, though.

Many thanks.

Another possible contact (from a sub-on-sub POV) would be a rainstorm on the surface, which apparently sounds an awful lot like a reactor. One shipmate of mine had spent his early career on fast-attacks, and he said they often lurked under a rainstorm. But you'd have to be pretty shallow for that.

And you are probably talking at least 5 ProbSub contacts per actual submarine in the water, with a minimum of 2 false targets per sub.

If you can use active sonar (say, patrol aircraft or surface ships), it's a lot easier to sort out the biologics from other random noise from an actual sub.

Submarines hate to use active sonar, since they just gave up their one big advantage: stealth.

Assuming that we're already in 'open season' where shooting is legal, the submarine will most likely be detected on opening/shutting torpedo tubes or crew-induced transients (like someone dropping a toilet seat. Yes, really.)

Or what Kelsey Grammer did In "Down Periscope"with his diesel pig,when pursued by a modern hunter-killer nuke sub,like using a supertanker on the surface as a "hat",or disguising it as a surface craft in stormy seas,putting on lights,and having the crew sing "Louie,Louie".

Sadly, submarine diesel engines (Fairbanks-Morse 38 8+1/8" for American subs) don't sound like surface ship engines (Detroit 8-71s or 12-71s, usually). They're much smoother and don't bang as loud. So the fishing boat trick doesn't work.

But hiding under another ship can work, if they are louder than you.

Lots of great surface contacts too, in lieu of periscopes – flotsam (plastic trash), seals, sea lions, whales, porpoise schools, sea birds, etc., etc..

From what I've read, snorting whales look surprisingly like snorting subs, from a distance.

I will of course claim a kill for each sonar contact I destroy.
If the game goes on long enough, I could claim every submarine in the world, except I would run out of depth charges.

Again, many thanks.