Primary it was just an excercise for boat designing. Then I thought maybe put an impeller on it, which was created by a friend. He use it for a little truck.
Finally we let it swim in a little bowl :-) http://youtu.be/emC3u8R1e5g
And here you can view Oliver's impeller-truck :-) http://www.youtube.com/watch?v=h_ZOYQsWkps
The best is, if you print it with spiral vase methode. Then you will get a neat surface without any noses from layer change.
The hull is 1.5 mm thick.
I printed with layer hight: 0.3 mm and width: 0.6 mm.
If you need to scale down you maybe need to reduce the width also because there must be a gap between the two perimeters. Otherwise it may not print continuous without stopping - even in spira vase methode.
I added a small base on aft to get more brim. I printed without heatbed and used 6 mm brim.
And yes, be very careful, if you reach the nose.
Reduce the temperature and speed by and by in small steps.