Final of the embarkment breakthrough is finished, after 19.5 hours. Water at subdiv setting of 0.75 with RT clouds and 2 soft shadowed suns (one to get the dark soft areas under the boats) took most of the time. It almost stood still when doing the last bits of water, so I paused rendering and set clouds to no-RT and decreased samples in soft shadows from 6 to 3, also decrease subdiv settings again to 0.25. Then continued rendering. No crash, luckily, but I've tried that before, so I knew it'd work. Rendering immediately increased its pace.
This is a part, can't show all. I'm quite happy with the result, though I should have changed a few things (like the footsteps). Up to the next challenge, which will be interesting too (medieval boat-pulling gear).