So I was finished with exploring Solstheim for a while, and I had gathered up a lot of goodies to take back to my home in Skyrim. I was definitely over encumbered from everything I had gathered to take back, but I thought nothing of it. I'd just slowly walk from my house in Raven Rock where I had everything stored to the docks and set sail for home. Well, the captain took my hard-earned coin for his trouble, the loading screen flashed up like I'm going somewhere, and *poof* I'm still at the port in Raven Rock. I rinsed and repeated a few times with no luck, cleared the cache and trying again. All I got was the same result, and 250 less gold each time for the fails.
Finally, I tried stowing away items until I was under the encumberance limit and I tried again. This time I arrived at the port in Windhelm, so I'm all set. My guess is that the ship to and from Solstheim/Skyrim follows the same rules as fast traveling by foot, and you can't do that if you're over your carrying limit. I wouldn't really consider this a bug except 1.) You get your money taken each time it fails to take you anywhere, and 2.) It is isn't very realistic. I mean, it's like renting a u-haul truck to do a move, loading it full of stuff from your house, and then discovering the u-haul can't move because it's carrying more weight than you can carry.
I guess I'll be making several trips to move my items for a while. If this issue has been posted before feel free to delete it.