You've got the top view of the hull in good shape. Now, it's time to work on the shape as seen from the side. Check the following steps:
Press 1 on the NumPad to get the Front view.
Notice that the hull is still oval shaped. As seen on the left of the next screenshot, the top is not flat.
Check that all the control points are level vertically. All of the upper points should be at the same height in Z. All of the lower points should be at the same height in Z. If any control point is higher or lower than what it should be, you can select it and scale it in Z, or move the vertices in Z.
Press Ctrl + R to activate the Loop Cut tool. Select the horizontal magenta line.
Move the orange line until it is almost all the way up to the top of the control object, as seen in the following screenshot on the right. This will control how tall and curved the deck is. There is an Edge Slide readout in the 3D View header. Move it till the Edge Slide is about -0.85...