December 22, 2017
Last month you may have read our article about Berthon being awarded the contract by Portsmouth Naval Base Property Trust, for the restoration and re-engining of the famous Motor Gun Boat 81 (MGB81). If not, you can catch up here.
Watch the short Video above for a time-lapse, with multiple interesting angles, of the entire engine removal.
Since then, work has begun and we have removed the 3 MAN 835hp engines to make way for 3 new, Mermaid Marine supplied, FPT C13 825hp more reliable, fuel efficient, and lighter diesel engines.
The entire aft superstructure, including replica twin 20 mm Oerlikon cannon and turret had to be removed, revealing a soft patch large enough for the engines to fit through.
With the aft superstructure safely stowed , Berthon engineers dismantled six exhausts and supporting brackets, the aft generator (which had been hidden in the stern from when she was a house boat), drive shafts for the port and starboard engines, prop shafts and props from all three engines, battery banks and the mid ship gear box (as this was mounted directly to the engine without a drive shaft); exhaust fittings and oil filters followed to enable the engines to be drained of all fluids reducing weight and prevent an unsafe lift before stowing them adjacent to the boat..
Two cranes were used to lift each engine out, one to lift the 1,900 kilogram engine high enough so that the sump would clear the engine supports, and the second to swing it into place before being lifted out. This intricate process involves patience and careful coordination as per the diagram below (or view the video coverage) And prior to the final lift and drop to shed floor level the first strop was reattached to the engine to act as an additional safety line.
The port engine was the first out, quickly followed by the starboard, the previously detached mid-ship gearbox, and mid-ship engine, which proved tricky to lift. Last to go were the port and starboard gearboxes.
With MGB81’s engine room clear an inspection of the frames and bulkheads ensued prior to the next phase from the following long list of work:
The deckhouse and replica gun will be replaced on completion of the engine installation.
Next month we will take you inside MGB81 for the beginning of a major replacement of structural frames and longitudinal stringers forward.
Watch the video Below for a first-hand and in depth view of the engine removal.