Final answer:
The convoy system was implemented during World War I and World War II to protect Allied shipping from German submarine attacks. It involved grouping ships together and using warships armed with depth-charges and sonar as escorts. This system significantly reduced the losses of Allied shipping.
Step-by-step explanation:
The convoy system was implemented during World War I and World War II to protect Allied shipping from German submarine attacks. The convoy system involved grouping many ships together and escorting them with warships armed with depth-charges and equipped with sonar. This system significantly reduced the losses of Allied shipping, and in one year during World War I, it cut the shipping losses by half.