From the 1750s, Portland Harbor was of economic importance as the closest American harbor to Europe and of strategic importance as a protected anchorage for the navy. As part of an upgrading of the harbor defenses in 1873, construction began on a battery at Portland Head to replace the outmoted granite forts in the inner harbor. This location ultimately contained six modern batteries mounting twelve guns and became headquarters for the harbor defenses.
Although the original battery was never completed, in 1891, work began on a larger, state-of-the-art fortification, along with four other seacoast forts: Fort Preble, South Portland, Fort Levett, Cushing Island; Fort McKinley, Great Diamond Island; and Fort Lyon, Cow Island. On April 13, 1899, the post at Portland Head was designated Fort Williams in honor of Bvt. Maj. Gen. Seth Williams, a native of Augusta, Maine and a veteran of the Mexican and Civil wars. The fort was manned during the Spanish-American War and World Wars I and II. Is also served as a recruiting, training, and administrative center for the Army Reserve during the Korean War.
At Portland Head.
Crew at Work on the Casemate Want More Pay or Shorter Hours.
Tuesday nearly the entire crew of 20 men employed on the new casemate at Portland Head left their job because they were obliged to work nine hour, instead of eight, as they desired. The work is done by contract and the contractor employs the men. They have been getting $1.75 a day, but thought they ought to get more than that or work but eight hours, because other employes of the government work only that time. The contractor yesterday morning put on a new crew of men and the steam drill was as busy as usual.
The casemate now in process of construction, on which these men are at work, is located in Ship cove, about half way between Cape Cottage and Portland Head Light. It is being excavated from the solid ledge on the farther side of the cove, and when completed will be an apartment entirely beyond the reach of any possible shot from an enemy's gun. In fact it is on the northerly slope of a high bluff, and cannot be seen from the open sea. It will have an entrance from the side nearest the city, but that door cannot be within range of any cannon unless the hostile vessel has passed entirely by and within Portland Head.
Within this casemate will be placed the apparatus for exploding torpedoes, which will be located at as many points as deemed necessary. The officer in charge of the exploring keys will not be able to see the approaching vessel. A signal officer will be stationed at the top of the hill in an observatory protected as well as possible from cannon. When the hostile vessel is over the torpedo he signals to the man in the casemate under the hill and a button is touched which will cause the destruction desired.
So much for the torpedo system. But as soon as the necessary appropriation can be obtained from Congress, it is proposed to mount on Portland Head about a dozen of the latest models of ten and twelve inch, breech-loading rifled cannon. These will be "disappearing" guns. That is, they will be concealed from the view of any approaching enemy and there will be nothing to attract an enemy's attention or indicate to him where the cannon are located. In a moment by the proper mechanism, the cannon will rise from the ground, deliver its shot and at the same time drop back into its former position, out of sight. As soon as possible cannon similarly mounted will be placed at various points on the outer sides of the islands. When all these defences are completed Portland will have no reason to dread any foreign war vessel.
Eastern Argus, July 23, 1891