stacels

So I started SP I have built a sloop 3 times now and it keeps disappearing/de-spawning. All I have to do is run out of render distance a bit in land and when I come back poof! no ship It's anchored on the shoreline every time in front of my base and when I come back the base is there but the ship gone every time. Anyone else got this? As you can imagine it's making the game pretty pointless.