Trilux 33 or Ultra 300 antifoul on an outboard powerboat hull?

[Spyros]

Which antifouling would you recommend for use on a hull of a 30 knot cruise/45 knot top speed outboard powered boat used in saltwater? Boat will be moored in a marina for 6 months every year and then on a trailer. Trilux 33 or Ultra 300? All experiences are welcomed.

 

[Tranona]

Any antifoul described as "Hard" suitable for use on powerboats (as opposed to soft erodable more common on sailing boats. Ultra 300 is International's offering in this category. However better to asl around in the location where you are keeping your boat as to which brand is most effective in their conditions. You may not get a definitive single answer but it may help you choose your brand.

 

[Chiara’s slave]

Almost every brand is now seriously deficient in actual poisons, for environmental reasons. The solution with a fast powerboat is regular use, and a few mins of proper high speed. We’ve tried them all on the race fleet in Yarmouth, no discernable difference. As we sail very slowly, but need a perfect finish only attainable with hard racing, we employ a diver to scrub the boats. It takes about 3 weeks in April/May to grow a coat of slime. Later in the year, big green patches appear between fortnightly scrubbings, and then you either scrub before every race, or shell out even more. I’m just managing expectations here. You need to use something, anything really, but take your own steps to keep it clean.

 

[crewman]

With a speed of 30 knots have you considered Silic 1?

 

[Neeves]

If Silic, or an equivalent, does not work at 30 knots - its a con. As mentioned you need regular use and a burst of 30 knots. If you do use Silicone, let us know the result.

Jonathan

 

[Chiara’s slave]

Silic would, in my opinion, require very regular use. I bought a boat with it on already. If any growth gets established, it gets roots into the coating and can never be removed. You could have to boat dry for 6 months and it will re grow within weeks of launch. Also it’s an utter bastard to remove. If anyone is stuck with theirs, I have 10 lites of unobtanium, silic one stripper. I’m saving it for a worthy cause.

 

[ChromeDome]

I went for a thin-film type that is smooth and has low toxicity. Doesn't build layers, tolerates up to six months out of water after application.
I keep the boat on the hard during winter and gives the AF a new coat every other year. Works for me (30' and up to 24 knots on shafts).

I get the thin film paint GTI30 from SVB24 (Germany). It is the same type as VC17 (teflon) but depending on location you might find it hard to get. Alternatives may exist, though

Edit: There are biocide free options (e.g. Hempaspeed) if you want or need.

BTW props and shafts gets Velox Plus on top of Hammerite Special Metals Primer (first time a total clean then 2x primer and the Velox, following years a high-pressure wash at lift-out, light sanding, thin coat of primer and new Velox before launching for next season).