Making modeling easier with Blender's layers function
A short while ago, you used the Move to Layer menu to hide the reference blocks, so you could render the boat. Blender's layers are a powerful tool and something that deserves a bit more study. Perhaps you may have used layers in Photoshop or Autocad. Blender's layers work differently:
In Blender, layers are similar to cubbyholes that you can put objects in, and hide them or show them.
Something on the top layer won't necessarily render on top of something on another layer. You cannot link them together, or move a layer as you can in Photoshop.
An object in a layer that is displayed can be moved, modified, or rendered. An object in a layer that is not displayed, may not.
There are 20 layers in Blender. You can use any number of them. You can select them with the 20 buttons in the 3D View header in Object Mode as shown here. They are called the Layer Visibility Controls, and they are shown in the next illustration. One half has a yellow border...