In September 1902 the First Submarine Flotilla, commanded by Captain Reginald Bacon arrived in Portsmouth. It consisted of two completed Holland boats and the gunboat H.M.S. Hazard that served as a floating submarine base. Captain Bacon recognized how dangerous the new submarines could be and proceeded cautiously with training his small band of volunteer officers and men. There were accidents and disappointments but just a few months later Captain Bacon reported that:

"Even these Little Boats would be a terror to any ship attempting to remain or pass near a harbour holding them".