VC17 does come in a version that contains the anti-slime agent "Irgarol" and is advertised as being effective in low-fouling saltwater environments, but for my money
, that's putting lipstick on a pig, not to get political or anything.
My experience with VC17 is that it is suitable for boats that normally never need in-water hull cleaning
and that means as close to zero-fouling conditions as possible. Irgarol or not, I would never recommend it for boats that live in saltwater.
Here's to hoping you prove me wrong.