Why does the navy throw people into the sea when they die and don't take them back?

Because in the era of geographical discovery in the 15th century, it was difficult to keep the remains of sailors who died at sea, even though the cost of keeping them was high. Rotting bodies may even bring danger to others. So the crew at that time were prepared to hand themselves over to the sea once they died. In fact, it is also for the safety of peers. Over time, it has become a naval tradition, and sailors who die at sea are buried by their companions at sea. Now it is regarded as an aspect of etiquette and naval honor. In fact, many courtesies in the navy evolved slowly from some seemingly simple truths, such as full lights, full flags, firing guns and so on.