Getting the screws back on alignment

The propeller drive shaft is one of the most important parts of the ship. During construction, the shaft is inserted with millimetric precision into the ship and interlocked with the engines. However, the rigours of maritime travel exert all manner of force into the shaft and the slightest damage will wreck the entire assembly, even trigger an unfortunate accident. As such, aligning the shaft is a tedious but important procedure.