Maybe hard Antifouling would be better?

Hi

i am due to come out on the hard and have just finished helping out antifouling my mates 47ft sloop. We recently purchased a hooker diving unit and I believe it will be a great benefit

in extending the the period between haulm outs. When cleaning the boat with a brush usng the hooker to dive I belive that the soft antifouling will be brushed off and i will loose the benefit of the antifouloing.

Would it be best to use a hard antifoul, I have never used one, can anyone comment on experiences with a hard antifouling??

[Bedouin]

I use a hooker to brush my 48' yacht. Use a dustpan soft type brush as the harder brissles don't work as well - figure that out!! I've got the thought that the light brushing doesn't remove the 'good' anti fouling and the anti fouling that may come off has probably lost it's effectivness. When a haul out comes about put on an extra coat of anti fouling for what might brush off in the brushing. Brushing seems to cut down on the regrowth for some time and that is what I'm basing my thoughts on.

Peter

[Jack Tyler]

Greexe:

The first issue is whether you wish to prime your hull, as you'll need to use the proper primer to hold on the ablative paint before you can put a modified epoxy a/f paint on top.

It's quite true - not only divers who run bottom maintenance services but yard operators will confirm it - that servicing a hard bottom will extent the life of the paint job significantly. Of course, this isn't free even if you do the work yourself: it takes gasoline (for the air compressor) or tank refills. But if it delays the hauling costs and the paint costs, it's a good deal.

Personally, I don't like using a brush. The best material I've found is a pad of white plastic material like you find on a hand scrubber - not the abrasive types but the white one that's quite soft. Divers usually use these and they measure about 1' x 5", so they cover a lot of area with a single swipe. Some divers use rug offcuts but of course there are many different types of rug materials so that recommendation is overly vague.

The most growth will be at the waterline, on the rudder, and on any (other) areas of the boat that get the biggest blast of sunlight. You might consider applying additional paint to those areas.

The more often you surface the bottom, the easier it is, the lighter you have to scrub, and the less 'real' (meaning: active) material you remove. Vicious cycle...

Jack

[JeanneP]

We usually hauled out and redid our bottom paint every 2-1/2 to 3 years. Here's how we did it.

After 3 years, a good power washing when the boat is hauled from the water (immediately, before the slime and growth has a chance to dry hard on the bottom), then perhaps a light sanding.

First coat of anti-fouling was hard bottom paint. Then 5 gallons (for a 40-foot boat) of ablative (soft) antifouling, in a different color (when possible) from the hard first coat (makes it easier to tell when the ablating bottom paint is almost gone). It is best to spray the self-ablating paint on. If no sprayer available, BRUSH it on. The problem with a roller is that you will be just pulling off the prior coat as you roll it on - just not as effective.

We had a 12V Hooka, home made, that plugged into the cigarette-lighter type outlet. Peter had installed on in our cockpit. You can see pictures of it at http://www.fototime.com/inv/19FAEC458BFF5BC

Please note that the truck tire inflater is a high-pressure, low volume air source. That is the reason for the accumulator bottles. Because of the high pressure, it is absolutely necessary that a scuba regulator be used. The pump is a diaphragm pump, so no oil gets into the air line.

Even though you would not be going very deep with such a hookah, I believe you must be knowledgeable about SCUBA diving to use it. Peter and I both took SCUBA lessons before we went cruising, and I do feel that use of gear such as this, or a commercial, hookah, requires the same knowledge as you get in a SCUBA course. You can do great harm to yourself if you make a mistake.

That said, this hookah proved invaluable to us for a lot of problems, such as cutting fishing net off the prop.

[Jack Tyler]

Jeanne:

Totally concur on the training related to use of a hookah; a very good point.

Could you say a bit more about how you dealt with a subsequent haul. Since ablative paint wears at different rates on different parts of the boat, wouldn't you find on hauling that you have some ablative left on the hull while the one coast of hard paint has lost its effectiveness elsewhere (e.g. waterline, bow, rudder). If so, you can't (well...at least, shouldn't) just lay on hard over soft in the areas where ablative remains. And from what I'm seeing in this yard right now, ablative paints don't just wash off with a pressure washer...without a LOT of additional effort. How did you two make that work?

Jack

[JeanneP]

I was amazed at how well it worked, actually. Pressure washing took off most of the soft paint, a light sanding of the hard coat to remove a thin layer of the older hard coat and we just put new ablative paint on. That hard first coat was still pretty good.

Twice, maybe 3 times, in the 18 years in the tropics we sanded down and replaced all paint, hard and ablative. Still a less labor-intensive and relatively cheaper way to do it, I think.