FOSS gamedev and creative worlds

I'm not sure that is the correct term, but this is the thing. I am working on LOTT, and I am trying my hand at blender for the first time (with Minetest of course). If you don't understand the term, this is my problem in two pictures:




The front face is transparent, but not the others. This makes it so the whole boat is skewed, and not playable with...

Can anybody help me?

On my phone so hard to explain. Google blender and "normals"
Hope that helps.

Yeah, you need to flip / correct your normals. The faces are pointing the wrong way.

*facepalm* ... *headdesk*

I should have thought of that. Thank you, Ruben...