They won't dive if you drift them, because they're floating lures, so they'll just sit on the surface. They need to be pulled through the water so that the bibs can produce a downward force.
What are you targeting in those spots? I'd have thought you might pick up a schoolie bass perhaps, but I'd have thought they would be better at somewhere like the Hurst Race, or along the back of Hurst Castle spit, over the bridge at the Needles, or even along the Hamble as you're motoring from Mercury to the Solent.