Quote from Khanromi
What are you placing the block on? There are certain blocks, such as grass and dirt, that can't be used as ship materials (though this is configurable). If you just plonked it on the ground, it won't work, you need something like, say, a bed of planks touching it.
If it's not that, I can't really help you without more information.
I'm placing it on wood. Thanks bro.