Cor,
They were the S-58GT's with PT-6-6's....we had the caravan on the tarmac....lived in the hotel for the longest time....and enjoyed every minute I was there. There is a story behind the GT remark.....blew the doors off a Puma one morning on the way to the Ekofisk.....and DE got dubbed a GT instead of a mere T.
Nick Lappos would have been proud of me over that one!