[bigboywooly]

Even if you sat on the bottom it wouldnt guarantee invisibility

Destroyer GURKHA obtained a submarine contact at 1412/9th southwest of Fair Isle in 59‑15N, 1‑08W and dropped six depth charge patterns in 59-07N, 0-44W. Destroyer ILEX stood by the contact while the convoy continued.
Destroyer FOXHOUND arrived from Scapa Flow at 0300/10th to stand by the contact and relieve destroyer ILEX. Destroyer ILEX rejoined the convoy before it arrived at Rosyth.
The submarine contact was later determined to be sunken steamer SANTOS.

http://www.naval-history.net/xDKWW2-4003-12MAR01.htm

Destroyers JANUS and ECLIPSE carried out six depth charge attacks at 1355 on a submarine contact in 59‑01N, 2‑24W. This contact was later found to be a wreck

http://www.naval-history.net/xDKWW2-4004-13APR02.htm

A submarine contact was reported by aircraft at 1233 in 59‑15N, 1‑30W. Destroyer ESCORT made an attack on a submarine contact and summoned destroyers TARTAR and JAVELIN from Scapa Flow to assist.
Further investigation proved this the wreck depth charged by destroyer CODRINGTON on 5 April.

http://www.naval-history.net/xDKWW2-4004-13APR03.htm

If a wreck can be picked then there is a possibility you could
Those 3 quotes are up until April 40

A little OT but

At 0400, destroyer KELVIN ran into KASHMIR's stern in 60‑28N, 2‑25E. KASHMIR's stern was badly damaged and Temporary Surgeon Lt J. N. Haggar RNVR, of KASHMIR, was killed in his bunk.
Destroyer COSSACK was ordered to tow KASHMIR to Lerwick escorted by destroyers ZULU and the damaged KELVIN.
At 1415, destroyer ZULU attacked U.19 north of the Orkneys after the submarine surfaced near the British ships. However, U.19 escaped with no more than light damage

Lucky U 19 eh

http://www.naval-history.net/xDKWW2-4004-13APR02.htm