why on ship machinery's are installed forward-aft & not port starboard?
Weight stability would be a primary factor.....You want the weight distributed along the center line
I guess it helps if the axis of the propulsion machine is in line with the propeller shaft so it doesn't need some sort of right angle drive.
It is easier to pick up the frame spacings for structural support running fore/aft as opposed to port/starboard
Depends on the designer... Machinery can be placed athwart-ship , fore and aft or a combination of the two if more than two pieces of the same type of equipment are installed. For athwart-ship placement at a given frame location, the numbering starts at the centerline and working outward even numbers go on the port and odd numbers on the starboard. For/Aft placement the numbering increases from bow to stern. Machinery is alway labeled starting at 1 even if it is located on the port side as would be the case of a single unit or the first forward most unit with additional units aft. Some factors that determine how and where machinery is placed include: size, weight, access for operation and repair, how critical the equipment is in relation to safe operation of the ship (number of backups or units to be run in parallel)
