A top speed of  was achieved, with the hydrofoil exhibiting rapid acceleration, good stability, and steering, along with the ability to take waves without difficulty. In 1913, Dr. Bell hired Walter Pinaud, a Sydney yacht designer and builder as well as the proprietor of Pinaud's Yacht Yard in Westmount, Nova Scotia, to work on the pontoons of the HD-4. Pinaud soon took over the boatyard at Bell Laboratories on Beinn Bhreagh, Bell's estate near Baddeck, Nova Scotia.
The hydrofoil reached a top speed of  and demonstrated rapid acceleration, stability, and steering capabilities, as well as the ability to handle waves with ease. In 1913, Dr. Bell hired Walter Pinaud, a renowned Sydney yacht designer and builder, to oversee the pontoons of the HD-4. Pinaud subsequently took over the boatyard at Bell Laboratories on Beinn Bhreagh, Bell's estate near Baddeck, Nova Scotia.