A harder antifoul paint perhaps?

[Alistair242]

We have had Altex #5 on our boat for the last few years and had to haul and repaint 6 months ago. We put on 3 coats. The first blue and then 2 coats of black. We hauled out in Queensland for storage in December and the blue bottom coat was showing in many places. This paint is really soft, chalky even. We still needed to scrub it softly every few months as there was growth. Most comes off underway and presumably takes a lot of paint with it.
We are heading north up into Asia next year and I think we will go with Micron AP(available in Oz and Asia) which claims to be slower polishing(harder but still ablative) and effective in warm/tropical water.

[johnmort]

PNW in Canada we use Interlux VC Offshore on our sailboat and Propspeed, we dive the boat once a month during summer excellent results with 5 years between hauling out.Getting 5years saves us on haulage fees which are considerable which justifies the slightly higher prices for the true hard bottom paints.
Other benefits are reduced fuel costs and a sail boat that glides through the water in light winds so no engine use or less use.
Boat is a Beneteau 47.7

[johnmort]

Using VC offshore compared to an ablative paint in hull speed we gained 1 knt massive savings in overall performance.Beneteau 47.7

[I14]

Similarly to some comments above we used to use a hard, scrubbable AF on our race yachts 40 yrs ago now (!) called 'E Type'. Certainly lasted well but had to be scrubbed fortnightly to monthly for race prep. I did some work formulating a waterborne emulsion based 2-pot which automatically made it harder and the Part B water miscible isocyanate will add to the cost. Will attach some photos from my raft here in Auckland after 20 months exposure. Growth here is bad compared to North America I believe and our marina has a reasonable water flow through it contributing to species diversity and growth rate. The Hydrosol shown is an aqueous low molecular weight solution acrylic which has the benefit of not being an emulsion so tiny holes in the film are potentially minimised but it doesn't seem to show any great advantage. I'm still using a standard solvent based ablative on my own boat...

[Alistair242]

Thats good to know. How does it perform in tropical water and how much paint do you need to sand off when you do haul?
Thanks

PS - Talking about the Micron VC

[fstbttms]

Originally Posted by I14

Growth here is bad compared to North America...

If you are cleaning monthly, your growth is no worse than California or most of the eastern seaboard.

[I14]

I don't know sorry, these have never been commercialised and being a boatie and a chemist I've always had an interest in the subject so they are experimental. Likewise I've never coated a whole boat with the waterbased product nor measured film removal rate through scrubbing but the formula fundamentals and the raft exposures show it to be likely as good as a standard ablative.

[davenrino]

Originally Posted by fstbttms

While Pettit did reduce the amount of copper biocide in most of its Trinidad products, they did this because of the development of new copper processing techniques that allows less metal to provide more anti fouling performance. Trinidad (any flavor) continues to be this professional hull diver's hard paint of choice and I recommend it above all others.

My boat is in the water year round in Honolulu and the bottom is professionally cleaned every month. I switched to 2 coats Trinidad and a third coat at the waterline 2 years ago. The diver says it still wipes off easily. I would have gotten at least another year out of it but I am coming out next week for a cutlass bearing. I will do Trinidad again while it is out.