Osmosis protection on 2010 Bavaria 40?

[Krumelur]

My new used boat, a Bavaria 40 from 2010, will need a new layer of anti fouling next season. It got this treatment for the past ten years.
My question is whether I should consider scraping of all layers of old coat and have a new 5/6 layer osmosis protection applied and then do the AF?
The surveyor could not find any signs of osmosis and the boat is out of the water every year from November until March.

I reckon, having the hull fully redone will cost me considerable amount of money and I honestly wonder if it's necessary?
Did the 40 get an osmosis protection in the factory when built?

[tiger79]

Bavaria hulls are very carefully moulded in controlled environmental conditions, and osmosis is pretty well unknown.  So I reckon you'd be wasting your money.

[Krumelur]

Just got a call from Bavaria Yachts: they say, an additional layer of osmosis protection is not necessary. Also, they don't consider 10 years to be an old age for a Bavaria.
They do however recommend to remove the AF down to the gel coat, sand it, apply primer and then new AF. According to them, after 10 years a considerable amount of AF has been aggregated adding to the weight of the vessel.

[SYJetzt]

I would'nt worry about the weight of the old AF-layers. Assumed a weight of the remnants of 5kg per year, and the cost of removing the stuff, i would save the money for other project.
If there are no loose patches after pressure washing it, i go on with light sanding and apply the next layer.

[symphony2]

Agree osmosis is a thing of the past. However there is some value in removing built up layers of antifoul, but if you are doing this properly with a view to keeping the boat a long time, then consider coating with Coppercoat. Material cost is not a lot more than epoxy and conventional antifoul, but more tricky and labour intensive. Well worth it, though in terms of the future savings in lift outs and new antifoul every year or 2.

[Krumelur]

I'm new to this, so forgive my ignorance.

At the end of the season, the boat will be lifted and gets a high pressure cleaning to remove the (slimy) fouling and algae.
Then, next season, new antifouling is applied. What's the process like?
Does one sand the old layer of antifouling and put on a new layer or is there another layer of primer painted first and then the AF?

I have an offer here for €1,500 to paint two layers of AF including material. That seems to be a lot of money? How much is the material for a 40ft Bavaria?
I don't see a reason to not do the paint work myself, unless it involves major sanding of the boat?

[symphony2]

Generally no need to do any prep before recoating unless there is excessive build up or pant is flaking off. Most AFs will go on without any primer - but check the data sheet of your chosen product. That will also give coverage and most manufacturers have calculators to work out how much you need, but guess between 2 and 3 2.5l tins. Some prefer rollers and some brush to apply. Do not use on the saildrive housing or around where the rudder stocks exit the hull, but use a copper free product such as Trilux.

Some people find applying antifoul as therapeutic, others the work of the devil. On that size boat it is a good solid days work. In UK cheap AF is £40 a tin, mid price £80, top £120, but in Euroland probably higher. So would guess somewhere around 5-600 euros for materials and the rest labour in your quote.

[SYJetzt]

In my case i do only a slight sanding to provide sufficient adhesion to the old layers. For my boat (B46) the coated area of AF is approx. 45m2, a B40 should be a little less. Calculation: LW(m)*(Beam(m)+Draught(m))*0,5 = coated area(m2). Needed amount of AF depends on Yield of AF per m2 (in my case 10m2/Liter and layer). 10 Liter were more than sufficient for my boat. Usually no need for a primer.
I applied  two layers ion the overall bottom, and applied the remainig amount of AF next to the waterline, where the growth of fouling is intense.
In my case the AF will last 2 seasons (in the adriatic), with scraping small barnacles off in a dive with snorkel at the mid of 2nd season.
Remember wearing protective cloth and face mask when sanding the old AF, which is a pretty nasty stuff.
Applying AF needs suitable weather conditions (dry weather, no rain, and temperatures above temperature like recommended by AF product manual). 
   
For full cost don't forget the liftout and -in, and other stuff when out of water, like changing anodes on saildrive and thuster, changing oil in Saildrive, polishing the hull, checking seacocks and rudder bearings,.. if necessary.

[Krumelur]

Thanks y'all! I'll give it a try next season.

[marioxp]

I'm new to this, so forgive my ignorance.

At the end of the season, the boat will be lifted and gets a high pressure cleaning to remove the (slimy) fouling and algae.
Then, next season, new antifouling is applied. What's the process like?
Does one sand the old layer of antifouling and put on a new layer or is there another layer of primer painted first and then the AF?

I have an offer here for €1,500 to paint two layers of AF including material. That seems to be a lot of money? How much is the material for a 40ft Bavaria?
I don't see a reason to not do the paint work myself, unless it involves major sanding of the boat?

We sending every year, because previus owner only applied AF and we had devil work to sending down. Two of us spend about 3-4 hours to send old layer down. Applying 2 new layers is easy, 1 hour job for two person. We use Jotun mare nostrum antifouling, spend 3x2.5L 36feet boat. One tin is about 110 eur in Croatia. I am not fully satisfied with Jotun so I am thinking to apply coppercoat.