A flat-bottomed boat is a boat with a shallow draft, two-chined hull, which allows it to be used in shallow bodies of water, such as rivers, because it is less likely to ground.
Man piloting a johnboat on the Speed River within Idylwild Park
Flat-bottomed boats on a pond, Château-la-Vallière, France
A trow was a type of cargo boat found in the past on the rivers Severn and Wye in Great Britain and used to transport goods.
Flat-bottomed boat
…Thames sailing barge Trow Horse-drawn boat…
Trows navigating a bridge over the Severn at Gloucester, showing the collapsible mast feature
The Ship Inn sign at Brimscombe featuring a Severn Trow
The Severn Trow Spry; 1908 painting