Yes Assistant Secretary Fox, whose highest rank in the navy was lieutenant, making this suggestion to the Flag Officer at the end of March, after the operation was already underway. Read the Navy's testimony to the JCCW. There was never a conversation during the planning, involving competent naval officers, as to whether it was even possible to do what McClellan planned for the navy to do.Fox, on the 24th March:
March 24, 1862
Flag Officer L. M. Goldsborough
My dear Sir
Gen'l Barnard has informed you of the plan of operations and the desire the Army has to have you strike a blow for them. I told the President that it must be left entirely to your judgment bearing in mind that your first duty was to take care of the Merrimac. He agrees to that, at the same time I don't like to have the Army say that the Navy could not help them, so we are ordering everything we can raise to report to you. The Sebago and Marantanza, (similar to the Octorara) will probably be in line, so will the Galena, iron clad vessel and you can probably bring back some of the North Carolina fleet, though they amount to very little. The Pawnee is ordered up from Du Pont's squadron. The St. Lawrence was ordered into the Potomac, in my absence, you can make what use you wish of her. Please send back the yard boats, and Potomac flotilla craft as fast as you can as they are much required here. If Burnside gets to Beaufort and the Nashville is destroyed, I fancy one sailing vessel will be enough off that port, so altogether you will have considerable of a force such as they are, before the army, is ready. If it is not enough I will take care to explain it, but if you can, I should like to see you knock down the town for them, they consider it as saving several months in the campaign. We want the Octorara to go South after this matter and the Merrimac is decided. The Propeller and Mail she has, better go by the Rhode Island.
The idea was definitely there and the Assistant Secretary of the Navy was mentioning it. His later testimony that it was never understood that the Navy was expected to reduce Yorktown can only be seen as suspicious on this basis, as the idea is present two weeks before McClellan reaches the Yorktown line.
Also see the later point on this matter.
But he wasn't there to see how many troops were in the defences on the 5th and the 6th. If there really were 5,000 troops to cover the whole of the Warwick line then making a rush is possible; if there were 13,000 troops on the 5th with more arriving on the 6th it looks very difficult indeed.
But then that means that Keyes held both positions, that the line was impregnable and that it could easily be forced. Why did he change his mind, and why should we trust one view rather than the other?
Speaking of testimony to the JCCW, Keyes is absolutely clear both in his JCCW testimony and his memoirs that he refused to consent to the Peninsular Campaign until he had recieved confirmation from the Navy that "the Navy was in a condition to co-operate efficiently to break through between Yorktown and Gloucester"; he is also clear that that confirmation was recieved from the Navy. So the plan was not agreed to until the Navy had confirmed that they were in a condition to cooperate with an attack up the York river (which is the only thing between Yorktown and Gloucester).
Keyes does state that "my impression now is that if the whole army had been pressed forward, we should have found a point to break through", but he states also of Yorktown that "in looking at the works after we got possession, I should say that in making an assault our loss would have been very great".
He does not state where the point that the line might be broken is, and he is clear multiple times that it is his opinion only that they could have broken through; in fact, when asked specifically whether they could have penetrated the lines (even with hindsight) he is clear that he will not say it was impossible, and that it was his opinion that it might have been done.
What it looks like to me is that Keyes (and Webb, and for that matter Magruder) are thinking of the Garrows approach, which is certainly the weakest point on the line. But to come across that point on the 5th or the 6th is a matter of pure chance, as neither of the roads up the Peninsula leads there.
Keyes also does not mention in his JCCW testimony that he was ordered to make a strongly pressed attack on the 5th of April, and he states that "I did not see any propriety in ordering an assault against such very strong works" in relation to Lees Mill. Thus at the time Keyes considered the position basically impregnable by land.
When asked directly "why was not the attempt made to carry those works immediately on the arrival of the army in full force upon the peninsula", Keyes makes no mention of the order he had to make a direct bayonet assault. This is an odd omission.