I'm using the Shaft Shark and yes it does work, in at least one verified circumstance. I also used a Prop Protector brand on my prior boat and it works too.

You'll find this is an issue all the way down the New England coast, and into Long Island Sound. Even in deep water, even in marked channels. Maybe not as much as Maine, but pretty thick in places where the bottom is rocky. You will need to keep a constant watch. In my home waters you can't sail or motor more than 10 or 20 minutes without needing to adjust course to avoid running one over. Sometimes you can identify a pattern when they're put down in strings.

Under sail, especially with a locked prop, you're less likely to snag one than when motoring. I avoid motoring at night, and if we need to motor into the sun when it's low we "tack" so the glare on the water doesn't hide them.

One other tip -- If your rudder has a notch where it meets the hull you should have a rod or small skeg protruding from the hull ahead of it and angled to deflect the trap-line down below the notch.