In researching WWII US Army port battalions I became familiar with other Transportation Corps units that served in port supply operations. The Army was were never very comfortable coordinating with the Navy, and it didn't want to rely completely on civilian boat workers. For the Normandy invasion the US Army created the harbor craft companies to man it's small supply craft, mostly barges, cranes, and tug boats. The War Department Field Manual FM 55-130: Transportation Corps Small Boats and Harbor Craft, published in 1944 gives a short description of the Army harbor craft company:
"The harbor craft company is a military unit organized for the purpose of ferrying cargo from freighters and transports arriving in theaters of operation. The vessels may either be riding at anchor offshore in the open sea or, which is more likely, anchored in a harbor. Cargo from ships is loaded by Transportation Corps port company personnel onto the barges. Tugs, tow boats, or marine tractors then propel these barges to the shore for unloading. Any cargo too heavy for the vessel's gear lift is handled by the 60-ton floating crane."
Harbor craft companies took part in the Normandy supply operations. Destination -- Berlin! The Transportation Corps will furnish the necessary transportation! was small booklet published by The Stars and Stripes. It mentions the contribution made by the invasion's harbor craft companies. It begins by marking the accomplishments of the 334th Harbor Craft Company:
"During August 1944 alone they performed 1403 channel operations. These army sailors towed 150 vessels and 288 barges into harbors, made 117 ferry trips, and threw in five salvage expeditions for good measure."
As with the port battalions, these rear area troops often came under enemy fire. The same Stars and Stripes booklet describes an incident in the supply of Cherbourg:
"The men of the harbor craft companies had a big hand in making Cherbourg a success. Harbor craft companies are an invention of this war and this theater. The first six companies were activated at the Charleston POE in May 1943. During the last war the Army depended on French civilian tugboats, but this time the enemy made that impossible. The Army had foreseen this situation and was prepared.
This is typical of what these companies were up against at Cherbourg: the crew of one ST-75 in a July 18 convoy from Southampton to Cherbourg was made up of men from the 328th and 335th Harbor Craft Cos. In a dense fog this ST-75 and five other boats became separated from the convoy about midnight. Fired on when be approached the shore on the following morning, the ST-75's ship's master set a course to the north. Before he could clear the Channel Isles, enemy shore batteries opened fire.
The first round took off the foremast. Seven of the crew went overboard. One soldier-sailor refused to abandon ship and went down. A sergeant was so badly injured that he later died. An officer was severely wounded in the leg. The survivors clung to a rubber raft until nearly dark the next day, when they were picked up by a British destroyer and returned to England."
In September of 1944 the immense port of Antwerp was captured by the Allies and it opened to shipping in November. Joining my grandfather's port battalion there were the 334th, 339th, 344th, 345th, and 352nd harbor craft companies. The port had been closed during the German occupation, and the Allies allowed very few civilian ships after its liberation. Consequently, there was a huge population of unemployed Belgian port workers available. The Allies hired the civilians to unload and transport the flood of military supplies. Soldiers from the harbor craft companies and port battalions were then free to perform other military duties in the port. My grandfather and many men from the harbor craft companies served guard duty on the supply ships, docks, and in the warehouses. They protected Allied supplies from black market heists while under a constant barrage of German V-bombs.