What happened to the ships bringing the food to Britain before WW2?

Before World War II, the ships bringing food to Britain faced significant challenges, particularly due to the increasing threat of German U-boats. These submarines targeted merchant vessels, aiming to disrupt supply lines and starve Britain into submission. As a result, Britain implemented measures such as convoy systems to protect these ships and ensure the flow of essential supplies. Despite these efforts, food shortages and rationing became a reality as the war progressed.