Draw a long curved line for the bottom of the boat
Add two short upward lines at both ends
Connect the top with a straight or slightly curved line
Draw a small triangle or rectangle for the cabin
Add a mast if you want a sailboat
Draw a triangle sail on the mast
Add a second sail if desired
Sketch a small window or door on the cabin
Draw a wavy line under the boat for water
Outline the drawing and erase extra lines