What antifoul to use on top of Nautix A4 T Speed

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dunedin

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Our boat has been antifouled using Nautix A4 T Speed for the past 2-3 years.

It seems more aimed at racing and power boats than a brisk cruiser like ours is - and seems to be fouling quite a bit.

Are there any constraints over what can be used on top of this - eg can one just slap on Cruiser Uno or whatever on top? Or is there a need to match types.
This is the supplier spec
http://www.nautix.com/Nautix/Nautix.nsf/511da3ce2e3f5b4dc1256d11004ff0d8/d03917a99f90d00ec1256cfc005aa827/$FILE/Nautix%20antifouling%20A4%20-%20data%20sheet.pdf

PS I really do not want to have to scrape it all off. The surface is good and scraping off would be a lot of work and potentially damage the epoxy underneath. If at all possible we only lift for one overnight to do the re-antifoul
 
The official line will probably be to apply a barrier coat of Primocon but as you can see Uno can be applied directly over all the other listed antifoulings in this table except VC17m

http://www.yachtpaint.com/LiteratureCentre/antifouling-compatibility-chart-gbr.pdf

Your Nautix A4 T is a hard antifouling and in practice I would expect to be able to apply a self polishing antifouling like Uno directly to it after washing in fresh water and allowing to dry

You could contact International's technical helpdesk for confirmation see http://www.yachtpaint.com/gbr/diy/contact-us/default.aspx

You could use Nautix A3 which is a self polishing antifouling that can definitely be applied directly to A4 T
 
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I just called them and as vics said they told me hard antifouling over cruiser uno no go, the other way round fine.

We are trying to go the other way......!
 
I would be speaking to the technical people for the top coating you want to apply and explain to them. I am sure some will advise applying a primer/sealer coat first. But having a contrasting, colour, hard antifoul under an ablative antifoul of compatible types is standard practice (though your hard is now worn). The contrasting colours tells you when the ablative is worn through.

Jonathan
 
I might have added, if you can get away with not using a primer seal coat - do so. it will save you time and money anyway. But your old AF has a little life left and its better than having primer as the surface under the ablating as primer has no AF quality at all!

Jonathan
 
I had Nautix A4 T Speed too (boat in the Med) and I absolutaly hated it. Even though I was using the boat very often (nearly every weekend all year round) the paint was doing nothing. During the last lift out, after a really good pressure wash from the marine yard, I tried with rough (sizes 80-120) wet papers to remove as much as possible, applied one layer of Nautix primer and then two coats of Nautix A3. After 10 months and still using the boat quite often the hull is still very clean. NEVER AGAIN a hard antifouling paint (unless you like to dive with diving gear once a month and clean it).

By the way I contacted Nautix and asked for guidance. Their best recommendation was to remove everything and start from the beginning. Their second best option was to sand strongly and apply the A3 on top of A4. Their last option (easiest) was to simply presure wash A4, apply primer and then A3 on top of it. I used a combination of 2 and 3 and I am very happy after so many months.
 
Looking at its specification it appears to have nothing unusual in it. I have had problems overcoating A/F containing teflon but not otherwise.

When applying Gelshield 200 it is recommended to apply a final coat of hard antifouling while the epoxy is still tacky. Eroding A/F is then applied over that.
 
SeaJet Antifouling gets good reviews. They have an antifoul paint compatibility webpage, link below. This states that if Nautix A4 T Speed is the paint to be covered then the Nautix T Speed has to be completely removed and the gelcoat primed for ALL of the various Seajet antifouling paints.

This doesn't apply to all Nautix antifouling, just those designated T Speed (A3 and A4). Maybe the slick 'Maxi Glide' quality of the T Speed products won't bond well with alternative antifouls?

http://www.seajetpaint.com/en/products/antifouling-compatibility-chart/
 
er..... maybe the T denotes Teflon? I don't actually know this and I haven't seen any mention of this on the Nautix site but the T Speed products are marketed as having 'gliding effect' qualities. If T Speed contains Teflon, maybe that's why it needs to be stripped off for all Seajet antifouls?
 
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