We put coppercoat on our boat in the UK in 2002 -

We then sailed it to Australia.

It worked everywhere except in Jolly Harbour in Antigua where the shallow sandy bottom caused the water temperature to be extreme.

Everywhere else it only collected a brown slimy deposit that wiped off easily with a 3M abrasive pad and a snorkel.

We eventually sold the boat and the new owner slipped her in 2017 - still no fouling other than the brown slime, but there was some minor tiny blistering due to the filler that had been used beneath the original bottom paint.

The new owner thus sanded off the old coppercoat and put on a fresh coat.

BUT I also know people who used the same product with very poor results.

I think the secret may be to put small quantities into the roller tray at a time whilst having a second person continually mixing the pot with a drill and a paint mixer as the copper is very keen to sink to the bottom.

You also require a lightish sand before launching to expose maximum copper.

Your mileage may vary.