Conventional Depth Charges?

[Jackonicko]

They're not listed in the RAF Equipment Factsheets, and I don't recall ever seeing mention of them as a Nimrod weapon, though the Shacks seemed to have them.

So when did they vanish from the golf bag, and why?

[Rossian]

I watched a stick of 6 dropped in the Moray Firth from a T4 Shackledrone in early 1965 if that helps. Watched from the prone position in the glazed tailcone it looked quite impressive. As I remember they were dropped from 100 ft and the escape velocity was not terribly high, but the spray was higher than we were. They weren't terribly effective because they were fused to detonate at 28 ft I think and most modern submarines could get below that depth pretty quickly. Apparently they were most effective if they went off at or slightly below keel depth thus producing an upthrust effect which broke the back of the boat. But I'm sure there's someone around who knows more.
The Ancient Mariner

[Si Clik]

Jacko,

We still have ours in the Navy, great for catching fish.

Si

[Yellow Sun]

The "why" is easy. They were no longer effective against the likely targets. The speed and diving capability of submarines had improved but there isn't much you can do about the performance of a conventional DC. It still sinks at the same rate and its lethal radius is still subject to the inverse square law. The new weapons in the inventory were much more effective, Mk44/46 so the least effective item can be dropped. The only area where the conventional DC might have been tactically useful was in shallow water (>100 fathoms). Not really the sort of area a submarine would wish to operate unless absolutely necessary. But if you were prosecuting a contact in that sort of area an MPA is probably not the ideal platform anyway.

The "when" bit I am not sure about. The conventional DC had certainly gone from the inventory by the mid 70s. It may have been listed as an option when the Nimrod came into service, but I very much doubt that any were ever released by squadron crews. If they were ever dropped it would only have been on the initial weapon release trials.

The Nuclear Depth Bomb (NDB) on the other hand remained in the inventory until approx. 1992.

YS

[MostlyHarmless]

Slightly OT...

Depth charge surfing (http://wiki.londonfns.co.uk/Dynamite%20Surfing%20%5bfrom%20www.metacafe.com%5d.wmv)

[Data-Lynx]

Jacko. Fishing again? A quick chat with colleagues suggests that helos from a number of Navies still have DCs for Sea Kings, Lynx and Super Sea Sprite. At the back of MoD Defence Standard 00-810 Issue 1 (http://www.dstan.mod.uk/data/00/810/14000100.pdf), dated as recently as 18 Aug 2006, Marking of Ammo and Associated Packages: Part 14 Underwater Weapons covers the Depth Charge Mk11 MOD3 HE.

[Jackonicko]

Yes indeed. Fishing. But quite specifically about non-NDBs on RAF land based ASW aircraft since 1965.

[Shackman]

The 250lb Depth Charge (As per MOTU Notes and as carried by the Shack)


Contained 180lbs of Torpex, and was designed to be dropped below 200ft/250kts. To release above 200ft a nose cap needed to be fitted - and they were in very short supply - and even then the max height only went up to 1000ft/250kts.

When dropped at 100ft and 160kts - standard pilot attack profile - the forward travel under water was approx 35 to 40ft, during which they would sink approx 30ft before making a big bnag!

The standard attack profile was a pilot aimed drop of 6 DCs over a 100yd length to straddle a moving periscope/snort with a line error of no more than 20yds. That way at least one DC (hopefully) would explode close enough to the hullso that the pressure wave caused by the explosion would cause major, if not fatal damage. The reason 6 were dropped was that the kill radius was very small - no more than 20-30yds at best.

Of note all the DCs I saw in the last years of the MR Shack were old WWII vintage, and quite rusty in places to boot. So much so that the first one I dropped you could push your finger through the casing! Even when we were disposing of the wartime reserves - again by dropping them in what were then active jettison areas - the latest date stamp I saw on them was 1945! Unfortunately I can't remember the mark of the weapon we carried, but I have a feeling the Navy weapons may be slightly different.

As YS alludes, they were not part of the Nimrod basic fit as the DC was not going to be as effective against modern submarines as the other weapons it could carry, and the attack profile was not suited to Nimrod ops. In addition, I don't think the 2 DC bomb carriers (Avro 144 and 169) were cleared for carriage in the Nimrod either due to size/compatibility problems, but that may be a red herring.

[pmills575]

As I recall the T4 don't have any glazing at the rear end.

Unless it was covered over later in it's life.

[sharmine]

http://www.dstan.mod.uk/data/00/810/14000100.pdf

See page 6 of the Def Stan (dated 2006). Good picture of one fitted to Merlin on the back of BAE Wavelength News Paper this Month. Talks about upgrade contract for the 60 year old design depth charge.

Goint to be around for some time yet.:ok:

Sharmine

[olddog]

Crew - Pilot. Target Sighted! Pilot Attack 6 DCs! Bomb Doors Open 100ft 160kts. Standby! Weapons Loose!!
Pilot - Tail. Attack Report 50/50 Zero Line.
Ah those were the days!!
Shackman's recollections are correct or does he still have a copy of the Shack weapons handbook?
As I recall, DCs were reserved for visual drops only, when part of the sub or the wake were still visual at the release point. The ideal drop was a 100yd stick 50/50 down the subs track.
I dropped a stick or 2 as a "highlight" of the MOTU course in 1967. Impressive ammounts of spray. I too remember the armourers being glad to see the back of some fairly ancient and rusty "tin cans" and seeing us off with instructions "not to bring them back"!

[Shackman]

They were all my own recollections (oh the delight of a 50/50 zero line!), but I do still have my MOTU weapons handbook (Vols 1 and 2). I'm not that much of a spotter/inky swot to be able to remember the serial numbers of the carriers in the bomb bay. I couldn't even remember them at the end of the lectures.


* * * Pertama * * *

[Pontius Navigator]

The point about DCs or torpedoes in shallow water is very true.

Bombs, cluster, HE or DC, are the only viable weapon for shallow water ops. SWO, by its very nature, will be limiting on the submarine in both speed and obviously depth.

The main reason for a submarine, invariably a conventional, on SWO would be for SF insertion. Now the kill radius of a DC against swimmers is rather better than against submarines!

In many waters a sub-surface submarine may be visible by day especially against a pale sandy bottom.

Helos, with DCs, are therefore an ideal shallow water ASW weapon, a high speed pursuit ship may spot a submerged submarine but will be much less able to relocate and deliver an accurate attack.

[Neptunus Rex]

You are absolutely right, Old Dog, the best way to get rid of rusting DCs was to drop them "Open Range" well out to sea. What an impressive sight. I am probably the last RAF pilot to have dropped a stick of DCs, but I cheated. It was in '73, over the Coral Sea, in loose formation with another Neptune, and I was on exchange with "Ronny RAAF." As the SP2H bomb bay was a lot smaller than the Shack, the stick was only five, but still enough to make the "sundodgers" eyes water. Happy days!
Neppy
:cool:

[Yellow Sun]

Neptunus Rex,

Please see your PMs

Rgds
YS