This is a bug in 1.3.1a, but there's a patch to fix it - replace data/core/structures/structures.xml (in your game files) with this file: https://cdn.discordapp.com/attachments/385203222396010508/460121338393264128/str... .
Thank you so much, I'm looking forward to visiting the other island. Unfortunately, my dockhouse is now invisible but that's probably something I did wrong.
I love your game btw, it's so addicting and interesting. The friend who told me about Aground said that it looks like Minecraft but after playing, it's obvious that there's way more to this. There are people to talk to, for one, which I think is vital. There's a plot and quests but it's also kind of open world/do what you want. There's more to mention but I've got a new boat to sail away in and I don't want to keep her waiting!
Keep up the good work! :)