trial & trial again...
Hi Pat,
at launch time this past spring i attached a collar type zinc fitting around the shaft, there was still about 1/3 of last seasons left from '07'...
when we hauled a few weeks ago there was about 1/2 of the new zinc left...
this is what worked for me at a mooring all season but you need to take into consideration where the boat will be kept and how much electrolysis will be around you...
some marinas will have more than others...
you can always put one on and check it monthly...
j&R