Go to: http://www.archiefalkmaar.nl/
(there is a sign for "English", but that only gives general information
than: zoeken op naam (namesearch)
than: click uitgebreide zoekopties (extended searchoptions)
type at achternaam (surname): Prins
type at voornaam (firstname): Jacob
than, bit further down; at plaats(town), choose: Oudkarspel
than, at the bottom, click start zoeken (start search)
and if everything goes as it should be you will find Jacob Prins
Than click on "Prins", and a window opens
left you see "inzien van de akte"
click on these words and you see two pages of the original birthbook of Oudkarspel. At the bottom of the right page, you see the birthcertificate of your Jacob Prins.
If it does not work, mail me and we can see how we can work it out. There is a possibility that you have to sign in.