Posted by Scott Andrews on June 05, 2000 at 13:40:31:
In Reply to: One more question Roy posted by Doug May on June 05, 2000 at 12:33:07:
Doug,
I hope Roy doesn't mind me sticking in my two cents worth:
: ...You mentioned that the ship was basically "empty" (with just the superstructure constructed) when launched? Did I understand you correctly? Were the engines not installed until after launching?...
: ...After all, if the decks and bulkheads were all in place at launch, there was still a lot of heavy pieces to be put into place inside the ship (any ship for that matter). Things like ovens in the kitchens, generators, motors, many of the heavy pieces... I wonder how they got these pieces installed after the decks and sides of the ship was constructed...
: Your explanation about removable plates that were bolted to permit removal-is that how access was obtained to install large pieces of machinery into the ship at the fitting-out dock?...
That's correct - the engines and other machinery for the most part would have been placed aboard after launching at the fitting out quay (pronounced "key"). When launched, the hull and superstructure are nearly complete in structure alone. The hull is little more than an empty shell at his point, with a huge amount of temporary timber shoring erected inside to aid in absorbing the tremendous sagging and hogging forces experienced during the launch. After the launch all of this is broken down and removed in preparation for outfitting to proceed.
Things like the boiler uptakes, the main engines and other massive assemblies would have been completely fitted and assembled in the shops ashore, and then broken down into units that were within the capacity of the shipyard's cranes and rail trucks. These units had also to be within a size that would allow them to fit down through the various boiler and engine casings, hatchways, and the designed-in removable plating that Roy has described.
In the case of the reciprocating engines, for instance, each cylinder along with it's piston, piston rod, covers and valve would have constituted a unit, or subassembly, as would the four individual segments of the base, each segment containing a portion of the crankshaft and the eccentric sheaves and pulleys for it's respective cylinder above. The turbine's lower and upper case halves and the fully bladed rotor each constituted preassembled units brought in turn to the ship, and reassembled aboard.
These steps of construction and assembly ashore, followed by breakdown and final fitting and assembly aboard apply to all of the interior joinery-work as well. Most of this work would have been started well in advance of the launch. The order to start work on the engines and boilers is generally given soon after the construction of the hull begins, the lead time to complete such complex machinery being great.
Regards,
Scott