Dix (i) says rowing boats continued to operate services from London to Richmond for many years after the introduction of steam. He says that he boats were called passage boats and were heavy 'randans' rowed by three men rather than the cutter claimed here. Traditional Thames cutters would fit the description of a randan to an inexpert eye.
(i) Dix, F Royal River Highway, A History of the passenger boats and services on the river Thames. p26
Nicholas Daly says that wearing gull feathers and body parts in hats had begun at least as early as the 1860s.
[Daly, N. The Demographic Imagination and the Nineteenth-Century City p168]
Favourite was built in 1817. It was owned by Gravesend Steam Packet Company 1817 to 1819 and by the Margate Steam Packet Company from 1820 to c1828 [Dix op. cit.p239]. The text implies that Favourite was visiting Margate when the song was written. If that is true the song can be confidently dated to 1820 (i)
In 1829, Favourite seems to have been moved to run between Lincoln and Boston and is depicted on this poster.(ii)
Poster for the Favorite Paddle Steamer, August 1828
(i) Dix, F Royal River Highway, A history of the passenger boats and services on the river Thames. p 239.
(ii) https://en.wikipedia.org/wiki/William_Pool_(engineer)
Margate Pier c1826
The Margate Steam Packet Company boat Majestic was built in 1816 and Victory was built in 1818;
[Dix, F Royal River Highway, A history of the passenger boats and services on the river Thames. p 248].
Victory approaching Margate with Favourite in the background