Now that you've made the reference blocks the right size, it's time to make the boat the same dimensions as the blocks:
Change to the side view by pressing the NumPad 3 key. Press Ctrl + MMB and the mouse to zoom in, until the reference blocks fill almost all of the 3D View. Press Shift + MMB and the mouse to re-center the reference blocks.
Select the boat with the RMB. Press the Tab key to go into Edit Mode, and then choose the Vertex Select mode button from the 3D View header.
Press A to deselect all vertices. Then, select the boat's vertices on the right-hand side of the 3D View. Press B to use the border select, or press C to use the circle select mode, or press Ctrl + LMB for the lasso select, as discussed in Chapter 4, Modeling with Vertices, Edges, and Faces.
When the vertices are selected, press G and then Y, and move the vertices to the right with the mouse until they are lined up with the right-hand side of the reference blocks. Press...