John and John;
This subject made me curious and got my interest, which lead to some digging, and this is what I found, for what it's worth.
1. - we know that 2x 17pdrs gun tanks of the 6th Cdn Armd Regt (1st Hussars)(Lt. Irving and Sgt Lamb crew commanders, respectively), were tasked with the engagement of a fortification next to Courseulles-sur-Mer during the run in to Juno, being mounted on the bow of an L.C.T. carrying AVREs of one of the attached Assault Sqns, R.E.
2. - L.C.T. (CB), I have found, referred to the Landing Craft Tank(s) which carried the assault squadrons of the Royal Engineers, which across the beaches - Gold: 50th Inf Div - 81 & 82 Assault Sqns, R.E.; Juno: 3rd Cdn Div - 26 & 80 Assault Sqns, R.E.; and Sword Beach: 3rd Inf Div - 77 and 79 Assault Sqns, R.E. - all of whom were equipped with AVREs. I have found nothing which suggests that L.C.T. (CB)s carried anything other than the Assault Squadrons, R.E. - there is nothing which points to any of these L.C.T. (CB)s carrying or employing 17pdr gun tanks for the sole purpose of 'Concrete Busting', except for the two 1st Hussars 17pdr gun tanks employed on Juno for the purpose of engaging a specific target (fortification next to Courseulles-sur-Mer)
3. - in an earlier post, I had mentioned, that in the Eastern Task Force, there were three L.C.T.s that 'carried 17pdr high velocity guns for destroying concrete defences' out of a total of 103 L.C.T.s that were mounted 'with army weapons' to give close fire support. (It does not say or specify if these '17pdr high velocity guns' were 17pdr gun tanks or the standard 17pdr A/Tk gun (carriage mounted)
4. - except for the 2x 17pdrs gun tanks of the 1st Hussars, that were assigned a specific task & target, I have found nothing indicating that any other 17pdr gun tanks were used for this purpose across Gold, Juno or Sword beaches.
5. - the AVREs were assigned the task of 'Concrete Busting' across all three beaches, hence the designation of L.C.T. (CB) for the craft which carried them.
General note: on the diagrams of the assault craft deployments, it shows the line of landing craft directing behind the swimming D.D. tanks to be that of the 'L.C.T (CB) AVRE', followed by that of the L.C.A.s of the assault infantry battalions.
Anyways Guys, just some points I dug up.
Cheers
