Page "Convoy" Paragraph 54

In practice, Type VII and Type IX U-boats were limited in their capabilities.

Submerged speed and endurance was limited and not suited for overhauling many ships.

Even a surfaced U-boat could take several hours to gain an attack position.

Torpedo capacity was also restricted to around fourteen ( Type VII ) or 24 ( Type IX ), thus limiting the number of attacks that could be made, particularly when multiple firings were necessary for a single target.

There was a real problem for the U-boats and their adversaries in finding each other ; with a tiny proportion of the ocean in sight, without intelligence or radar, warships and even aircraft would be fortunate in coming across a submarine.

The Royal Navy and later the United States Navy each took time to learn this lesson.

Conversely, a U-boat's radius of vision was even smaller and had to be supplemented by regular long-range reconnaissance flights.