This may belong under the 'Gear & Maintenance' category but I could not find a suitable sub-category for it so here it goes.
Every estuary, bay, sound and coastal area is a little different in regards to how much bottom growth occurs on your boat. The location may be important but the prevailing local weather is also a key factor in my little corner of the globe which is now the Hudson River near the Tappan Zee Bridge in NY (northeast region).
Last spring and early summer saw a lot of precipitation which meant that there was a lot of fresh water coming into the Hudson valley estuary I normally sail on which in turn meant that the barnacle growth on our hull and prop was minimal at best. This season has proved to be fairly dry with much less precipitation then last year and therefore more salty water has invaded farther up the Hudson then last year.
Around this time last year when we hauled our boat for a mid season bottom cleaning there was mostly slime with only a few small barnacles clinging to our prop. It was a very easy power washing job to clean the hull and minimal scraping of the prop (more on that later). We hauled our boat out this year and lo and behold there were numerous barnacles with some advanced clusters that resisted the power washer. We had to resort to scraping and power washing to get most of the growth off the hull.
The salinity levels are higher this year in the Hudson watershed because of the reduced amount of rain which is evidenced when you drive around and the grass is not as green as it could be on the edge of the highways. Last year was good for all land based plants and slime (algae) but bad for barnacle growth. This year seems to be the opposite.
I have been treating our 2 blade prop with the Petite Zinc Coat barnacle barrier for a few years with varied success. Last year we had very limited barnacle growth; very small immature barnacles. This year I suspect that the clusters were a bit bigger due to the temps and salinity. I still plan on using this product next year as the coating protects our prop from the barnacles attaching directly to it which also protects the metal of the more expensive prop underneath. The Zinc Coat forms a very tenacious bond with the prop and thus a protective layer against marine organisms and from me when I try to clean it in the late fall when we haul out for the winter.
Anyone in the northeast US or anywhere have any anecdotal evidence of how the marine growth is trending in your area?