Complex sentence: Their nicknames by Steam Packet staff for both the "Maid" and the "Ben" in the 60's and 70's were the money boxes, as they gained the Steam Packet all its profits via the carriage of cars and vans.
Split into simpler sentences: Their nicknames by Steam Packet staff (both the "Maid" and the "Ben") in the 60s and 70s were the money boxes. As they gained the Steam Packet all its profits via the carriage of cars and vans.