Wooden peg = "treenail" = "trunnel"

I encountered "treenail" (also "trenail") for the first time in a report from Rhode Island about old wooden ships eroding out of seaside sand dunes:

Seaweed drapes much of the eroded woodwork — timbers nine inches square extending from keel to gunwale and still covered in part by strakes, wooden planks that run from stem to stern. Here and there a green stain betrays the occasional metal pin, perhaps of copper, but the hull is held together mostly by wooden pegs...

They’re called treenails, pronounced “trunnels,” said D.K. “Kathy” Abbass, founder and director of the Rhode Island Marine Archaeology Project.

Abbass said that method of ship construction dates back centuries, but maritime traditions die hard.

“Wooden pegs don’t really help” in determining the age of the ship, she said. They only began falling out of fashion in the last century. She said the yacht Coronet, which is being restored by the International Yacht Restoration School in Newport, is built treenail-fashion.

Via Professor Hex.