Glass it. boat soup wont save it, and the added structural strength will keep you from sinking when you put a foot through a seam and it inevitably opens up. No harm done as is far from historical preservation. The Island is named Quinnebaug, meaning long pond, but more likely
USS Quinnebaug (ID# 1687)
Quinnebaug (S. P. 1687), formerly Jefferson, was built in 1899 by Delaware River Iron and Shipbuilding and Engineering Works, Chester, Pa., for the Old Dominion Steamship Co; chartered by the Navy 3 December 1917; converted to a mine planter by Robbin's Repair Basin and Drydock Co., Brooklyn, N.Y.; and commissioned at Brooklyn 28 March 1918, Comdr. David Pratt Mannix in command.
time frame fits, as the owner was a haberdasher from Long Island who summered on Georgian Bay early in the last century and would have passed the builder on the rail, before the steamship took them to the island