Prow of a boat You can draw a shape in a drawing program as Macromedia Freehand, Adobe Ilustrator, Corel Draw or
InkScape (a Free software) and export your draw as a JPG image.
In SketchUp, in Top View, import the image. We are going to use it as a template.
With the Arc Tool Clic on the extreme points and draw the arc to match the image.
Close the shape with the Pencil Tool and extrude the triangle with the Push/Pull Tool
Clic on the upper border with the arrow. Select the Move/Copy Tool and drag the selected border out (to right in the image) on the red axe.

Now, clic in the blanc to deselect. With the Move/Copy Tool drag away the upper border again from the MidPoint.
Now select all the model. Put the Move/Copy cursor over the selected model and press Ctrl. Youll see a + sign. Now drag in the red axe to copy all the model.
With the copy of the model selected, choose the Scale Tool. Some greens squares appears. Put the Scale Tool cursor over the one you see in the picture. Press Ctrl and drag in Red axe. Strech it, continue draging, past trough and when you reach the oposite border theres a kind of "stop" (you can continue draging but we dont need that now). "You can start to drag, then type in , -1 followed by return key , and the mirror will be created." ("Tip by jpwade")
OK. So you flipped the copy of the model.
With the Move/Copy Tool move and join the 2 halfs (take care)
Now enlarge the image to see in detail. With the Move/Copy Tool join the points.
Watch the axes 
OK. Here you have the boat prow!!
Tip: Be patient...and practice as necessary... 