Further enquiry, however, nearer the scene of construction indicates that an error had been made in the wording of the item, which had apparently been copied into the other papers without verification.
In the library of the Historical Society at Buffalo is deposited the manuscript diary of Capt. Van Cleve, who sailed as clerk and as captain on the Martha Ogden, the next steamboat to be built at Sackett's Harbor six years after the Ontario. In this he writes, "the construction of the Ontario was begun at Sackett's Harbor in August, 1816." He also gives a drawing, from which all subsequent illustrations of the Ontario have been taken. Further information of the American steamer is given in an application for incorporation of the "Lake Ontario Steam Boat Co." made in December, 1816, by Charles Smyth and others, of Sackett's Harbor, who stated in their petition that they had "lately constructed a steam boat at Sackett's Harbor"—"the Navy Department of the United States have generously delivered a sufficiency of timber for the construction of the vessel for a reasonable sum of money"—"the boat is now built"—"the cost so far exceeds the means which mercantile men can generally command that they are unable to build any further"—"the English in the Province of Upper Canada have constructed a steam boat of seven hundred tons burthen avowedly for the purpose of engrossing the business on both sides of the lake."
All this indicates that the American boat had not been launched and in December was still under construction.
It is more reasonable to accept the statements of Capt. Van Cleve and others close to the scene of operations rather than to base conclusions upon the single item in the publication issued at so far a distance and without definite details.
It is quite evident that the item in Niles Register should have read "was lately commenced," instead of "was lately launched." The change of this one word would bring it into complete agreement with all the other evidences of the period and into accord with the facts.
No absolute date for the launching of the Ontario or of the giving of her name has been ascertainable, but as she was not commenced until August it certainly could not have been until after that of the Frontenac on Sept. 7th, 1816. The first boat launched was, therefore, on the Canadian side.
The movements of the steamers in the spring of 1817 are more easily traced. Niles Register, 29th March, 1817, notes, "The steamboat Ontario is prepared for the lake," and Capt. Van Cleve says, "The first enrollment of the Ontario in the customs office was made on 11th April," and "She made her first trip in April."
The data of the dimensions of the Ontario are recorded, being only about one-third the capacity of the Frontenac, which would account for the shorter time in which she was constructed. The relative sizes were:
| Length. | Beam. | Capacity, tons. | |
| Frontenac | 170 | 32 | 700 |
| Ontario | 110 | 24 | 240 |
No drawing of the Frontenac is extant, but she has been described as having guards only at the paddle wheels, the hull painted black, and as having three masts, but no yards. The Ontario had two masts, as shown in the drawing by Van Cleve.