How much Antifouling?

R

robmurray

Well-Known Member
Joined
30 May 2001
Messages
128
Location
Live in Marlow
Visit site
I am sanding down and applying 2 whole coast of Blakes Tiger Extra plus another along leading edges each winter. Someone has told me that I am putting on too much and could just scrub off every other year - is this true? The boat is in the Hamble and performance is important.
 
I'd put on the absolute minium - you need the gelcoat underneath *just* covered and another coat means more weight - to no particular advantage if you haul out every year imho. In fact, if the rules state you need antifoul, I wd strip to gelcoat and have one coat. Next year you can rub down and just titivate or apply the lighest of coats. Most boats seem to apply tons of antifoul as though is a garden fence. Actually, garden fences don't need that much paint either - just enough to protect them...
 
Surely you know not to get any particles of old antifoul in your lungs? Even wetted down, particles can migrate - watch out - wear a proper mask.

I find the following:

1. Growth is more concentrated at the waterline so double up here (12 inches) in the knowlesdge I will brush down 1-2 times in the height of the season to freshen up this area. The rest gets one coating only.

2. If the underlying antifoul is pitted or broken, it's time to scrape back and apply antifoul primer to get a better grip

3. Fouling during the season is of course dependent on water temperature and how much nutrient there is in the passing water at the moorings. I find that in a marina the concentration of antifoul is higher so growth is inhibited by my neighbours.

4. I cruise much of the summer and get away with a lighter coating of antifoul, and not the most expensive either! But I find that moving the boat almost every day has a great impact in reducing slime and growth. Your rate of growth will be much higher if you are only moving a few hours a week, at most!

PWG
 
It was explained recently in a club magazine that barnacles only release their fertilised ova mid-summer; the tiny larvae develop and attach to the nearest available hard surface. They then settle down to a year of the quiet life until it's time to repeat the life-cycle. Theoretically, then, the time to antifoul is just before this happens; or the time to scrub is just after. You cannot get new barnacles at any other time of year. Trouble is, this is mid-season - cheaper for the lift-and-scrub but a pain if you're busy enjoying the sailing. Slime and weed is another matter, of course.

I vote a Nobel Prize goes to the scientist who can explain why barnacles seem to enjoy being whizzed round and round on my propellor - maybe the 'quiet life' is just too, well, quiet ?

Brian
 
Boats require 2 full coats applied to hte thickness that the manufacturer recomends, for a full 2 years protection from growth.

Commercial ships get 5 full coats evenly applied (supposedly) for 5 years protection. The antifoul on ships is basically the same other than the larger and less pretty packaging.

However the ships are professionally surveyed annually by divers with cameras, with surveyors/inspectors watching the survey live. because of these inspections and the cost of hauling a ship/ lost revenue, and the antifouling costs, this is more practical and economical commercially.

However on your own pleasure boat, ensure two full coats and a gentle in ater scrub a feew times a season and you will get the best economical performance from your own boat.
 
[ QUOTE ]
(cut)
I vote a Nobel Prize goes to the scientist who can explain why barnacles seem to enjoy being whizzed round and round on my propellor - maybe the 'quiet life' is just too, well, quiet ?

Brian

[/ QUOTE ]

Do you put antifoul on your propellor? If so does it stay on? Copper propellors won't get barnacles, but they won't last long either! Barnacles settle every where, it's just that some don't survive. Bronze is inert, if not antifouled & not running all the time the larvae are about it's bound to pick up the little blighters.
 
I would suggest that minimum antifouling will give you more time between that dreadful major scrape off of the buiuld up.
If you expect to winter ashore and repaint before launch then experimentation will determine just how much a/f you need to last the summer.
Re Sailing Doc comments I think that is way off the mark. Certainly around here fouling comes from a variety of creatures in fact weed is a bigger problem than barnacles which perhaps do take a 12 monnth cycle. I get little critters a bit like tiny prawns that attach within a few days on non a/f surface followed by slime that grows into weed. finally very tasty mussels appear. But of course your local experience should prevail.
Lots of my friends put 4 litres on their 21 ft boats just cos it comes inn a 4 litre can. Yes they get huge a/f build up.
I can make 4 litres last 3 or 4 seasons and ensure that by, in water scrubbing there is very little left by the time of repaint.
On the other hand I wait till the season warms up until I paint. Then with weekly scrubbing it lasts about 3 months. But that is my peculiarity an arrangement which wouldn't suit all and certainly not in UK.
The bottom line is, use as little a/f as possible and experiment over a few seasons. olewill
 
[ QUOTE ]
I vote a Nobel Prize goes to the scientist who can explain why barnacles seem to enjoy being whizzed round and round on my propellor - maybe the 'quiet life' is just too, well, quiet ?


[/ QUOTE ]
Not worth a Nobel, but AFAIK:
Barnacles are basically stationary, so they feed best at places where food is brought to them. So, the faster the feed, the bigger they grow, and the more numerous they get. The quiet life is for weeds and algae.
If you sail less, then you get more slime (bacteria) and algae. If you sail more, then you get more barnacles. On the hull, the barnacles tend to multiply on the spots with the most turbulation and highest water speeds. This is typically around the front of keels, and the deadwood in front of the prop . And the more copper (and a few other metals ) you have in bronze, the less likely the prop will be fouled. However, a dark brown oxidation layer on the prop shields the barnacles from direct contact with the native copper, so they are very happy there, as they are rotating happily with fresh food brought to them.
 
Hi
After years of applying two coats every year we tried using only one (Cheapskate). It seemed to work just as well except on the leading edge of the rudder and keels where there was more abbrasion. So I now give them two coats. That is using Tiger in Gosport and applying it once a year. A lot less build up as well of course.
 
[ QUOTE ]


Commercial ships get 5 full coats evenly applied (supposedly) for 5 years protection. The antifoul on ships is basically the same other than the larger and less pretty packaging.



[/ QUOTE ]
I thought commercial ships were still allowed to use TBT. In which case it's nothing like what we're left with.
 
You must log in or register to reply here.

Share this page

Top