The presidency is often defined by the Oval Office, but for nearly a century, some of its most consequential moments unfolded aboard vessels that served as a kind of floating White House.

The first government-owned presidential yacht, USS Despatch, was refitted for Rutherford B. Hayes in 1880. Thereafter, a succession of presidential yachts – sometimes more than one in service at a time – stood ready for the commander in chief. These boats – Dolphin, Sylph, Mayflower, Potomac, Williamsburg, Honey Fitz, Sequoia and even John F. Kennedy’s ocean racer on loan from the Coast Guard, Manitou – reflect a little-known tradition of leadership conducted just offshore, beyond the reach of Washington, DC.

They were tools of diplomacy, places of decision and, at times, the only spaces where a president could think clearly beyond the reach of crowds.

In 1910, President William Howard Taft sailed the 273-foot Mayflower along the Maine coast. His wife, Helen Taft, observed that such voyages offered rare moments of rest – "steaming away out of the reach of crowds" – perhaps the only way a president could truly step back.

Time at sea was something like an escape

Three decades later, Franklin D. Roosevelt turned to the water for similar reasons. In March 1941, speaking by radio aboard the Potomac, he reflected that time at sea offered "a chance for a bit of sunshine or a wetted line, or a biography or a detective story or a nap after lunch." More importantly, he said, it allowed a........

© USA TODAY