Just a couple of updates on the information you listed.

PD 46 > CRETECOVE
Grounded at Røssøyvågen in 1942, where it currently lies. Local pilot was overruled by the germans, whom promptly grounded the barge.

PD 141 > CRETERAMPART
1924 - sold to JW Robertson in Lerwick and used for salvaging german destroyers at Scapa Flow in concert with Cretemanor.

In addition to that, I've discovered information about a concrete barge DPC55 - (Aftenposten 15.10.1935), but I'm unable to link that to any of the existing crete barges.

Digitalized norwegian ship registers points at the existence of a Crete-series barge in the Oslo area.

AM8 - [media.digitalarkivet.no] (Registered 1942)

Aker 9 - [media.digitalarkivet.no] (Registered 1975)

These could concievably be the same barge. I've contacted the last known owners in 1981 (Kavringen Marina) and await a reply from them.

They did have another concrete barge in their jetty, but this was a german Seeleichter Wiking Motor which was buried in 2015.

Should we also include OC502 Cretefuel, the oil barge which sunk outside Grimstad 21.3.1947?