Is it permissible to shorten prayers (qasr) when continuously traveling between Egypt and Saudi Arabia and staying on a ship, knowing that the distance covered is approximately 150 kilometers, the duration of stay in each country does not exceed three days, and this work is lifelong?

It is permissible to avail oneself of the concessions of travel (shortening prayers, combining prayers, and breaking the fast) for someone whose journey distance is that of a "qasr" (the minimum distance for which concessions are allowed) and who does not intend to stay in a particular place for four days or more. This includes those working on ships, as long as the ship is not their permanent place of residence, even if the travel duration is long. The permission to avail these concessions begins when one departs from their city of residence and continues on the journey and at ports of stopovers, unless one intends to reside in one of them for four days or more.