Boat like entities

first, add this to your imports:
import net.minecraft.util.math.AxisAlignedBB;
import javax.annotation.Nullable;

then, add this somewhere in your code (if you're in doubt, add below the registerGoals function):
        @Nullable
        public AxisAlignedBB getCollisionBoundingBox() {
          return this.getBoundingBox();
        }

not mine i just found it on the mctoolkit server

can you go more in-depth? i have the same problem and have no idea what imports are...

https://ibb.co/hMPj8fL

so go into your mobs code and add the code that starts with imports under somewhere in that list (i dont think it matter where)
and then with that bottom part of code add it anywhere else in the mobs code just not in imports

I tried it too and it didnt work either so I guess its just the wrong code, I dunno I thought it worked