Watermen and Lightermen

 Watermen

A waterman [or wherryman] is a river worker who transfers passengers across and along city centre rivers and estuaries. Using a small boat called a wherry or skiff they would ferry passengers along and across the river. With bad rural roads and narrow congested city streets, the Thames was the most convenient highway in the region. Until the mid-18th century London Bridge was the only Thames bridge below Kingston upon Thames. [2]
The trade goes back to Roman times and before but was first licensed under Henry VIII 500 years ago. [3]

[1] https://commons.wikimedia.org/wiki/File:Thames_waterman_soliciting_passers-by_c_1825.jpg

[2] https://en.wikipedia.org/wiki/Waterman_(occupation)

[3] http://www.thameslightermen.org.uk/ 

Lightermen

A lighterman is a worker who operates a lighter, a type of flat-bottomed barge, which may be powered or unpowered. In the latter case it is today usually moved by a powered tug. The term is particularly associated with the highly skilled men who operated the unpowered lighters moved by oar and water currents in the Port of London. [2]

A lighter is a type of flat-bottomed barge used to transfer goods and passengers to and from moored ships. Lighters were traditionally unpowered and were moved and steered using long oars called "sweeps" and the motive power of water currents. They were operated by skilled workers called lightermen and were a characteristic sight in London's docks until about the 1960s, when technological changes made this form of lightering largely redundant. Unpowered lighters continue to be moved by powered tugs, however, and lighters may also now themselves be powered. [3]

[1] https://commons.wikimedia.org/wiki/File:A_lighterman_standing_on_the_bow_of_a_lighter,_hauling_on_a_rope._RMG_L8581.jpg

[2] https://en.wikipedia.org/wiki/Lighterman

[3] https://en.wikipedia.org/wiki/Lighter_(barge)