GrahamHR
Well-Known Member
As paul said they need more looking after than every four years!!!!
I would say every two at an absolute max. We did ours in March after they where last done when we bought the boat in October 2008. This was pushing it and one of the anodes was very worn. On top of that we had water contamination in the outdrive oil. Had we left this it would have started to cause problems.
I'd recommend the anodes be checked more often than once per year, especially if the boat is in a marina; the erosion rate can vary from year to year, I did have to change mine 5 months into the season one year with my previous boat (Thankfully it was one Summer when the water got reasonably warm!). My current boat one has the active corrosion protection unit fitted, the anodes now last more than 1 season.