This self unloader has a 250′ boom that can be positioned. It is built for my 614′ and 735′ Great Lakes bulkers.
The elevator house occupies the two rear hatches. The boom is positionable. This all-styrene kit is easy to build. Rigging is left to the modeler, as it will depend on the positioning of the boom. It is shown on my Z scale model of the AlgoSteel, a 735′ Fitzgerald-class Laker.

4.6C. Extensible 250′ Unloader
Great for modern versions of 610′ and 730′ Lakers. Completed model discounted with purchase of base Laker. US Shipping included; international inquire at peterknolan@gmail.com.
$300.00

4.6K Extensible 250′ Unloader
Kit with boom and 3D printed elevator house. . US Shipping included; international inquire at peterknolan@gmail.com.
$245.00
Hello, I need a self unloader for my Great lakes freighter. My ship is 40″ long by 4″ wide. Will this kit work on my ship?
I don’t know what scale your ship is modeled in. A Z scale unloader would certainly fit; the N scale unloader might be too long. The length of the unloader is determined by the reach off the ship to the shore, as transport of the coal to the unloader is internal to the ship.
The scale is 176th.
That’s about 587 feet long in scale. I can cut you an unloader in 176th scale, or either N or Z will do fine. There’s nothing very scale-specific in these mechanisms.