The submerged ends of the ship, the Secretary refers to as novel, were ends extending beyond the shield under water to obtain speed, buoyancy and protection by submergence.
"And if Lieutenant Brooke presented rough drawings to the Department carrying out the same views, it may be called a singular coincidence."
This singular coincidence becomes significant, but less singular, when considered in connection with the return of the ship-carpenter to the yard, prior to the construction of Mr. Porter's model.
Mr. Porter then describes his model correctly: "Submerged all 'round two feet—sides and ends"—and then proceeds to say, "and the line on which I cut the ship down was just in accordance with this."
But this was the characteristic or novel feature of Lieutenant Brooke's plan, which the constructor had been ordered to put in execution. Mr. Porter ignores the existence of the original plan, and overlooks the fact that the extension of the submerged ends in that plan was not made to suit the shield, but to obtain buoyancy, speed and protection. It was not necessary to submerge the ends of the vessel in order to submerge the eaves of the shield.
"But if Lieutenant Brooke's ideas, which were submitted to the Secretary in his rough drawings, had been carried out, low enough to build tanks on to regulate the draft of the vessel, she would have been cut much lower than my plan."
Constructor Porter knew that the depth of submergence was two feet, and that to use the superstructures as tanks to regulate the draft was merely incidental; they were to be filled with water at fighting draft and emptied, if necessary, to diminish it.
Extracts from these three letters of Mr. Porter will be found in J. Thomas Scharf's History of the Confederate States Navy, published in 1887, pp. 146-151.
The last in order is the extract from a private letter, given above, which, Mr. Scharf says, was published in the Charleston Mercury of April 8th, 1862.
Knowing that this extract, the first publication connecting Mr. Porter's name with the Merrimac, had appeared at an earlier date, I wrote to Colonel Joseph Yates, whom I had known as one of the