Sid, on the hand grenade issue. Hand grenades were not part of the designed ammunition load for U-boats but are often mentioned POW interrogation reports so it can be assumed that they were carried aboard U-172. The KTB uses the words "Handgranaten neben die Bordwand geworfen." It is clear they are talking about throwing a hand grenade and not firing a shell. Also, the sea state was 5 so operating the 10.5 cm cannon would have been difficult. Regards, Jerry