Wreckages spawn at random points on the map, once per hour, regardless of tick speed. Unless they've changed that recently of course. But that's how it was lol.
Never seems like 1 per hour.
Not that I seem to have much luck with Wrecks, they're never anywhere near me in the early ticks. On the other hand, I did get one with a spam yesturday from a 22 tick attack