Iain M. Banks's 1987 novel Consider Phlebas (the first Culture novel) features a spaceship landing on a huge oceangoing liner in an even huger artificial ocean, on a mind-bogglingly enormous Culture Orbital.
Consider Phlebas is set during the Culture-Idiran War. The Culture decides to strategically withdraw from a volume of space, to do this they decide to evacuate and demolish an Orbital with billions of inhabitants. (Vogon Prostetnic Jeltz, eat your h...oh wait).
One of the attractions on this particular Orbital, Vavatch, are huge ocean-going vessels, called "Megaships" that sail around the Orbital-girdling ocean. But now they're CAM fodder.
The main character, a Changer named Bora Horza Gobuchul, is an agent of the Idirans. He was rescued after a space battle by some scavengers who wanted his spacesuit. He had to fight and kill one of the scavengers to earn a place on the crew.
Horza's been ordered to capture the story's McGuffin, a lost Culture Mind, and so he plots to kill the scavengers' captain Kraiklyn and take his place.
Horza sees his chance when Kraiklyn decides to loot one of the empty Megaships before the whole thing is demolished.
That's tame compared to what happens after the scavengers' ship lands on the Megaship.....
This just in: Since your question was inspired by the SpaceX floating autonomous landing platforms, just be aware that SpaceX founder Elon Musk actually chose the names Just Read the Instructions and Of Course I Still Love You as an homage to Iain M. Banks's Culture novels. The Minds controlling Culture ships and other structures choose names like these for themselves, and it's one of the more entertaining details of the whole Culture millieu.