Is it Halvoson or Halvorsen????
I know it was your Dad's boat and you grew up on it and is has great history and heritage but if you go miss spelling the designer and or builder's name, you will blow your whole act.
The discerning buyer will pick you up on it, particularly if you are going for the "Classic Collectible" market.
Spectacular Achievement is ALWAYS preceded by Unspectacular Preparation and that includes getting your spelling right and use of capital letters right.
Just trying to be helpful here.

http://www.boatsales.com.au/used/halvorsen/