In May 1836, he took out a patent for propelling vessels by means of a screw revolving beneath the water at the stern.

He then openly exhibited his invention at the Adelaide Gallery in London.

Sir John Barrow, Secretary to the Admiralty, inspected the model, and was much impressed by its action.

During the time it was publicly exhibited, an offer was made to purchase the invention for the Pacha of Egypt; but the offer was declined.
At this stage of his operations, Smith was joined by Mr.Wright, banker, and Mr.C.A.Caldwell, who had the penetration to perceive that the invention was one of much promise, and were desirous of helping its introduction to general use.

They furnished Smith with the means of constructing a more complete model.