Before & After - Bottom Paint

	Before & After - Bottom Paint (2009)

	Bottom paint is an essential maintenance project for every boat that stays in the water year round. This is kind of essential when your boat is too big to trailer as Mouse Pad is.

	How long does bottom paint last? How do I know when to paint the bottom? Those questions can only really be answered by you and your diver. I know that in some areas of the country or world diving to clean the bottom is prohibited and the boat has to be hauled and pressure washed.

	I’ll take the easiest one first, the WHEN? Your diver should give you a report every time he gets out of the water. This usually takes the form of a tag attached to your boat which at a minimum will report the effectiveness and coverage of the paint as well as the condition of your zinc anodes. The effectiveness of the paint reflects the loss of ability to reject biological growth or he sees the primer or other coating showing through the current paint color (bottom paints are mostly red, blue, or black). My diver leaves the tag but also calls me if he sees anything out of the ordinary. Out of the ordinary is when I am burning through zinc anodes at a faster rate than usual or he sees a different color paint showing through. On one such call recently was when he told me of the white stripe on the hull and keel.

	As to the question of how long does paint last? It varies dramatically from area to area, even from marina to marina! I most areas a good bottom paint job should last a few as two years and as long as four years. In Southern California I have found that most boats bottom paint will last from three to four years. I have found that pressure washing reduces the life span of bottom paint as it removes more paint than a careful diver will by using a diaper. Sorry but your life span will be drastically reduced in most cases to two to three years at most.

	Some of the reasons that can contribute to paint degradation are; water temperature, amount of use of the boat, local biological activity, how often the bottom is cleaned, and how good your diver is in his cleaning job. I have my diver use a diaper, or soft cloth, to wipe the bottom so it doesn’t take any more paint off than necessary but removes any growth that has built up since the last cleaning. I also built in a precautionary coat of bottom paint. What is a precautionary coat? When I had Mouse Pad stripped and fresh barrier coats put on back in 1997 (just before going on my first cruise (Cruise ’97)) the very first coat of paint put on was BLACK. Now when the diver sees black paint when he is cleaning I know I am down to my very limit and need to schedule a haul-out soon and put on some nice new red copper paint.

	How often should you have your bottom cleaned? That is up to you and your local water conditions. I have Mouse Pad’s bottom cleaned every month so there is nothing more than a wipe with a diaper needed.

	It has been almost three years since the last time I painted Mouse Pad’s bum. My diver has been reporting that the bottom is still in good condition and is still rejecting the growths of the marina… except for one area where he told me that there is a white strip extending from the thru-hulls mid-ships (head area). Well I was not only surprised but bewildered as to why there was a strip down there? Until I thought hard about the location and possible reason… hmmm!!! Oh No!!! I remembered that a couple of months back the hoses from the head had become partially blocked, not an unusual issues for a live-aboard, and being a bit lazy and wanting to try and find a quick out I had poured some heavy liquids down the head (kind of like Drain-O). Seems that it didn’t clean the pipes at all, as I knew, but it was such a heavy liquid that it dribbled down the side of the hull and stripped the paint, instead of the blockage in the pipes.

	So my advice is that short cuts don’t work. Take the pipes out, clean them or replace them and get over it. This is what I ended up having to do anyway!

	As you can see in the photos Drain-O type products don’t play well with bottom paints and actually strips them to the core. I had to not only go through the usual prep-work for a paint job but had to primer the nice white strip from the Heads thru-hulls down the entire hull and keep to the very bottom. I had to admit that this time I had the yard perform the preparation work, all I did was paint the bottom.

	What paint to use? As a cruiser the best paint I have found is Pettit Trinidad Red, as it has the highest copper content and is very aggressive towards not letting algae, grasses or other biological grow on your bum. As for painting the bottom I used Interlux B-90 paint (Red) which has about the most copper content of all available paints and is almost the same as the Pettit Trinidad. It is heavy and takes a while but well worth the extra effort. It took four gallons of paint for the entire job. It is a great paint but costs the most, currently West Marine sells it for $249.00 per gallon. There are much cheaper paints and if you are just a local sailor then you can consider other more ablative paints. Check with your local boat yard or painter to see what their recommendations are. Oh, and don’t forget to ask you diver as he sees them all and will tell you which one lasts the best. No matter what brand of paint you decide on please check around as deals are always to be had (in Ventura I found the B-90 ranged from $145 to $249 per gallon).

	Applying bottom paint: First you need to make sure that either the yard where you are painting your boat or the place you purchase the paint will shake it up for you. With the four gallons we purchased it took a full 40 minutes to mix each of the first three gallons and the fourth took over two hours on the machine for the fourth gallon. It all depends on how long it has been sitting on the shelf. We painted the entire hull and keel with two full coats. The water line, leading edge of the keel, rudder, and bow got two or more extra coats as did the very tip of the keel. These are the most affected areas by propeller wash (leading edge of rudder & skeg), ultra-violet (water line & bow), etc. What tools did I use? Simple it took two 4 inch paint brushes and three rollers. The paint brushes were used to make sure we gots lots of coverage on the skeg and the leading edge of the rudder where it sits up against the skeg and up inside the thru-hull fittings. I find that rollers with a medium or fine nap are best for a smooth and even coverage, rollers with a heavy nap (those made for ceilings) will work just as well but give you a lot more splatter and you will end up with as much paint all over you as there is on your boat!