What is "double-bank"

Double-bank \Dou"ble-bank"\, v. t. (Naut.) To row by rowers sitting side by side in twos on a bank or thwart.

To double-bank an oar, to set two men to pulling one oar.

vb. 1 (context nautical English) To row (a vessel) by rowers sitting side by side in twos on a bank or thwart. 2 (context nautical English) To set two rowers to pulling (a single oar).