As a matter of fact, Joshua Slocum’s “Spray” was a semi-abandoned, rotting, 36’ Oyster boat that had been propped up in a pasture for 7 years when it was given to Slocum in 1892. Nearby Oak Trees fell victim to Slocum’s hand axe to provide the timber needed to rebuild the boat.
As for decked over Life Boats, following WWII many life-boats were converted to sailing cruisers, particularly in Holland and England where there were an abundance of abandoned ship’s boats and frugal—read poor—but ingenious would-be sailors. In 1951 one Michael Verney authored “Practical Conversions and Yacht Repairs” dealing with the conversion of Ship’s Boats from 16 to 30 feet while another author, one John Lewis, authored “Small Boat Conversion”, the supposed best book on the subject which detailed his own conversion of a 26’ life boat to an auxiliary ketch. These “conversions” proved very robust and seaworthy—living up to their names (“lifeboats”) and made some fantastic voyages. On that, remember that in 1789 William Bligh navigated a 23 foot open ships boat on a 47 day, 3,600 mile voyage from a point near Tonga to Timor in the Dutch East Indies; and, in April 1916, Ernest Shackleton navigated a partially covered lifeboat—the James Caird—from Elephant Island in the Antarctic Sea to South Georgia Island in the South Sandwich Islands over 15 daze that included enduring a hurricane.
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."