The photograph above shows a Babcock Steambloc TC50 boiler in the new Machine & Assembly Factory at Babcock Power Ltd’s Renfrew Works on 16th March 1981.
The boiler was being prepared for despatch to Finnieston Quay, Glasgow where it would be lifted into the boiler room of Waverley by the Clyde Port Authority’s giant cantilever crane. This photo was taken by either David Murray or Duncan Mawer who were the two official Babcock photographers at the time.
The boiler was a three pass gas-tube unit with a watertube membrane-walled combustion chamber between the first and second passes. The boiler was ‘non-standard’ with several modifications to suit Waverley.
The TC50 shell was larger in diameter than a boiler of the design steam duty would normally require. This allowed a redistribution of generation surface producing a greater water depth above the top gas tube level to reduce the likelihood of ‘dry-out’ when the vessel was rolling in swells during her positioning runs in exposed sea areas.
The shell was about one foot shorter than a standard TC50 shell to fit Waverley’s confined boiler room space, reduce weight and to ensure that the unit was not running at too great turn down at the normal steaming load. The boiler was fitted with two oil burners of the rotating atomiser type supplied by Saacke Ltd. The burners came with close mounted drive motors and fans.
The Steambloc boiler remained in service until the Heritage Lottery Fund Phase 1 vessel rebuild in 1999-2000 when it was decided to replace it with a two-boiler system to provide some degree of redundancy capability in event of unit failure.
By that time Babcock in Renfrew had sold its Shell Boiler intellectual property and withdrew from that market. Therefore, the Company, by then Japanese owned and renamed Mitsui Babcock Energy, did not tender for the second reboilering contract in 1999.