
Thanks Busia

http://www.boatzincs.com/
Simply type MARINETTE in the search box and a listing appears with the boat lengths and amout of anoids required.

ALSO

From Marinette Yacht site.
Anode specifications for Marinette aluminum boats
Material:
Although anodes are commonly referred to as "zincs" the proper anode for use on the Marinette hull is actually a specially developed aluminum alloy with the designation of KA90 or SEALLOY 150. These aluminum anodes, because of their material make up and the processing that they go through, give the highest protection possible. KA 90 and SEALLOY 150 were the anodes that the boats were supplied with from the factory. Magnesium can be used, however Marinette Yachts does not recommend its use. If magnesium is used, it can only be used in freshwater and it will deplete at a much faster rate than the aluminum anode possibly leaving the hull unprotected if not monitored closely. Commonly available zinc is too close on the galvanic scale to provide adequate protection and should not be used. High purity zinc can be used but it is difficult to find and does not provide as much protection as the aluminum anode.
Attachment:
Anodes should be bolted to bare metal with Stainless Steel bolts. Do not use wire brushes made of steel or copper alloys to strip the aluminum.
Anode requirements:
26', 28' and 29.5' Models
30" on each side of keel, 12" on each trim tab, 6" on each rudder, Total single engine 7' 6"
Total twin engine 8' 0"
32' Models
36" on each side of keel, 12" on each trim tab, 6" on each rudder
Total 9' 0"
37' Models
54" on each side of keel, 12" on each trim tab, 6" on each rudder
Total 12' 0"
39', 41' and 44' Models
60" on each side of keel, 18" on each trim tab, 6" on each rudder
Total 14' 0"
bill