Divided control of the forces in that area was partly responsible for this.

The Austrian destroyers were considered by the Italian Admiralty to be so serious a menace in the Adriatic as to render it necessary to keep in that sea the great majority of the Italian destroyers as well as several French vessels of this class.

The situation at the eastern end of the Mediterranean necessitated a force of some eight British destroyers being kept in the Aegean Sea to deal with any Turkish vessels that might attempt to force the blockade of the Dardanelles, whilst operations on the Syrian coast engaged the services of some French and British destroyers.

Continual troop movements in the Mediterranean also absorbed the sendees of a considerable number of vessels of this type.
Consequently there was a great shortage of fast small craft for escort and mercantile convoy work.

It was estimated that the escort force required for the protection of a complete system of convoy in the Mediterranean was approximately 290 vessels, the total number available being about 215.
In spite, then, of the success of Admiral Calthorpe's work, the result was that convoys were not started in the Mediterranean until October, and they were then but inadequately protected, and losses were heavy, both from this cause and from the fact already mentioned--that the Mediterranean is a sea which, by reason of its confined nature, is particularly suited for operations by submarines against trade.