Former WW2 Poortershaven mini submarine base. Two advanced bases were prepared at Poortershaven and Hellevoetsluis at the Waal/Maas estuary. The main base being Rotterdam. 30 Biber and 30 Molch minisubs were sent here. A further 60 Molch and 30 Biber were sent from Helgoland and Groningen respectively. 60 more Biber would arrive in the area in January 1945.
December 22/23 1944 - 18 Biber sailed from Poortershaven and Hellevoetsluis. The operation ended in failure. British MTBs surprised the Biber whilst still being towed and instantly sank four. One was mined and one returned damaged. The remaining 12 disappeared.
Biber (Beaver) minisub http://upload.wikimedia.org/wikipedia/commons/b/b4/Biberrsm.jpg
Search for WW2 Poortershaven