Despite the overall poor performance of the T-5 acoustic homing torpedo after its introduction in the autumn of 1943, I've noticed from the reports on uboat.net that the Canadians suffered particularly badly from warship losses resulting from T-5 attacks. Specifically, from the time of the T-5's introduction to the end of WW2, every Canadian warship sunk by a U-boat was as a result of a T-5 torpedo attack.

I noticed this pattern on a page in uboat.net's members area which listed every Allied warship lost to a U-boat during WW2. There is a a similar page in uboat.net's public area (note - this page also includes losses to causes other than U-boat attacks):

Canadian warship losses - [uboat.net] (starting with HMCS St. Croix, 20 Sep, 1943)

Some of the sinking reports linked from that page don't mention the torpedo type, so I did some digging around on Google...

HMCS Esquimault - [www.mysteriesofcanada.com]

HMCS Regina - [uboat.net]

HMCS Valleyfield - [uboat.net]

(for some strange reason there is more detail on the Regina and Valleyfield in uboat.net's Merchants database than in the Warships database)

...and found that all the RCN's losses to U-boats were indeed due to T-5 (GNAT) torpedo attacks.

I'm aware that the RCN, like the RN, used noise boxes as a countermeasure - so their ships were not defenceless against these weapons.

Can anyone here offer some insight as to why RCN ships were so (apparently) vulnerable to acoustic homing torpedoes? Perhaps the RCN's noise boxes were not as effective, or in very short supply?