Mark VI Mine and New Online Exhibit

This is a Mark VI mine on display in the museum's gallery. During World War I, the St. Juliens Annex of the Norfolk Naval Shipyard assembled over 100,000 of these weapons. The U.S. Navy's Mine Laying Squadron One deployed about 70,000 of them in the North Sea during an operation known as the "North Sea Mine Barrage." The goal was to seal off the North Sea as an exit point for German U-boats.

The mines were quite advanced for their day. The sphere contained 300 pounds of TNT, more than enough to rip an 800-ton submarine apart. A U-boat would trigger the mine by touching either the sphere itself or the wire cable located above and below the charge.  The mine's trigger, however, was possibly too sensitive as there were many reports of deployed mines exploding due to other objects in the sea such as fish or floating debris.  The Navy stored surplus mines at the newly-established Yorktown Mine Depot in Yorktown, Virginia. Today the facility is known as Naval Weapons Station Yorktown.

In cooperation with Commander, Navy Region, Mid-Atlantic, a new online exhibit about St. Juliens Creek Annex and the mines can now be seen at the museum's website.