This is a typical image of the structure in question: There are also some variations, shown in this Google image search. But I'm after the often not very wide, some 20-30 feet long wood construct
Yankee Magazine March/April 2015 by Yankee Magazine - Issuu
Nautical (Sailing) Terms (Words & Phrases), Nomenclature and
Rowing Glossary - St Hugh's Boat Club
The Sailor's Word-Book William Henry Smyth - Get a Free Blog Here
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the Conquest of the Great Northwest, by Agnes C Laut—A Project
Oar - Wikipedia
What were medieval ships called? - Quora
terminology - Accurate British English term for an oblong deck from shore out into a lake where you tie your rowing boat - English Language & Usage Stack Exchange
Rowing Glossary - St Hugh's Boat Club
grammaticality - On the air OR On air - English Language