I use Foryn Gilnith's Shack as my Morrowind base of operations, so I travel back and forth between Old Ebonheart<->Ebonheart<->Seyda Neen all the time on boat. Slowly each time I take these boat paths the sailor NPCs at Seyda Neen (Sentius Veros) and Old Ebonheart (Aeta the Spear) are pushed a little bit further away every time. The one on the Seyda Neen dock has already fallen off of the dock and into the water, and the Old Ebonheart one is getting close to falling off the dock as well.