Here is a summary of the article in "The Engineer", July 3, 1863, p. 63 (unfortunately in the copy I have, the dotted lines are poorly visible):
The object of these improvements, by Captain Blakely, of the Army and Navy Club, is that the opening of the breech may be affected by the act of firing, so that the parts leave in a position to receive a fresh charge. For this purpose the breech-piece projects into the barrel, and is retained in position by weight or elastic pressure
[underlined by me, as one of the most important future point] proportionate to the power exerted by the pressure of the charge in firing. The firing cause the propulsion of the projectile, and at the same time the recoil of the breech-piece, thus opening the parts for the supply of a fresh charge. The breech-piece enters the barrel to an extent sufficient to insure in not leaving the breech end thereof until the projectile passes out of the muzzle.
The breech-piece is affixed to the block, which has groove formed on each side of it to receive the rails, projecting from the end of the gun, by which the block with the breech-piece is supported, to be capable of sliding to and from the breech end of the gun in a line with the bore. The block has be drawn towards the barrel by a weight, which is connected to the block by chains, other end of each of these chains is connected to the weight, and thence passing over a pulley. The weight serves also as table for the fresh charge and projectile pervious to its being driven into the gun, and, by preference, a fresh charge is placed on table, whilst the weight is holding the breech-piece in the breech end of the gun. When the parts are in the position indicated, with the table raised, that table will hold the fresh charge correctly opposite the bore. The parts, as shown, are in the position after the firing, when the effect of the recoil has been to force out the breech-piece with its block, thereby overcoming the force exerted by the weight. And in other that the block with its breech-piece may then remain in the position indicated until a fresh charge has been introduced, there is applied to the weight a pawl, and to the framing a rack, by which when the weight has been elevated, it will be held up with the fresh charge thereon in position for loading. This charge must then be forced a short distance in to the gun, and then by lifting the lever handle affixed to the pawl, that will be released from the rack, when the weight will descend again and draw the breech-piece to force the charge fully into the chamber of the gun.
So, we collected all elements that actually existed among the Americans by the time of the laying of the New Fleet. By this the real-historical preamble ends, and begins the "amble". Well, let's now try using these elements to assemble a puzzle by name "New Fleet". Let's start, again, with what the American concept was based on - with the new ordnance.