You assigned the material to the boat, planar mapping the material to the side of the hull to get a horizontal waterline.
You then applied an Unwrap UVW modifier to adjust the coordinate points of the hull so the blue hull color and the white deck color were near the gunwales and followed the slope of the deck.
The waterline remained horizontal.
This same method can also be used to create interesting landscape contours.
Make as many colored bands as you like and apply planar mapping to the side of a landscape mesh.
Use material Blur and Blur Offset settings to blur the color transitions.
The bitmap image does not have to be horizontal bands of color.
Use the 2D Line to create odd shapes before converting to Editable Mesh objects.
You are called upon to create an animation showing two rows of five simultaneous explosions and time is of the essence.
It would take too long to render a scene with that many Combustion objects on the computer you have available.
The answer is a series of mapped 2D explosions.
You can create an explosion in an empty scene and render that explosion to an AVI file.
The AVI file will then be used as a Diffuse and, again, as an Opacity map to create a material to be applied to objects in a new scene.
This process will save on overall rendering time.
Use the Cinepak codec by Radius for good results with most AVI files.
For extra interest, you can add Omni lights synchronized with the blast cycle to give the appearance of a flash from each blast.
The material used as a diffuse color map and as an opacity map to give the planes color only where the explosion occurs and not over the entire flat plane.
Each flat plane has a 'Look at' controller pointing to the camera so if the camera were animated in the scene, the blasts would always face the camera.
This gives the illusion that the blasts are 3D, but they render very quickly because the blasts are only a material on a simple plane.