K, it's all subjective.
With all due respect for the way you experience it:
To me "Rock The Boat" is more Disco than R&B. I see black dance music from 1973 through to the mid 80"s, and prior to "house" and Euro disco, to be the best era for "it's got a great beat and you can dance to it" black music, as they used to say on American Bandstand lol...
Imho most R & B music, the way I define it, was released on Atlantic Records, Chess, and Stax just before Motown opened the white teenager market to black music, which changed a lot of the black music full R&B style to a more cross-over friendly style from those afore-mentioned labels, plus Hi label in the south, and the Philadelphia Soul International "Philly Sound" in the north, and a whole bunch of independents.
Throughout I considered funk to be R&B, and James Brown was doing pure R&B until he brought funk into his repertoire. Some say he invented funk...
I love it all!