Between November 1945 to November 1947, the small harbour at Aberdyfi and the mudflats/sandbanks at mouth of the estuary were used for training by Royal Army Service Corps Amphibious Training Unit at Towyn. A hulk was moored in midstream to act as a focal point for crossing. An aerial photograph dating to 1 May 1946 shows a line of six `buffalo? (amphibious tanks) entering the Aber Leri channel from the south (Ynsylas beach) and heading northwards.

Sources include:
Green, C C, 1993, The Coastlines of the Cambrian Railways: Volume 1
RAF aerial photograph 106G.UK.1450-3150, RCAHMW Collections

Maritime Officer, RCAHMW, January 2010.