Kautilya's Arthashastra 2.28.13

2.28.13

śāsakaniryāmakadātra..raśmigrāhakotsecakādhiṣṭhitāś ca mahānāvo hemantagrīṣmatāryāsu mahānadīṣu prayojayet, kṣudrikāḥ kṣudrikāsu varṣāsrāviṇīṣu //

In those large rivers which cannot be forded even during the winter and summer seasons, there shall be launched large boats (mahánávah) provided with a captain (sásaka), a steersman (niyámaka), and servants to hold the sickle and the ropes and to pour out water.

Small boats shall be launched in those small rivers which overflow during the rainy season.