How close did naval guns need to be for shore support?

What was the effective range of 32-pounder and 18-pounder naval guns?

Roughly a mile or a little more, while the supporting ships at Guadeloupe could operate only a few hundred yards offshore.

The estimated range of 32- and 18-pounder naval guns was roughly a mile or somewhat more. The useful point at Guadeloupe is the fleet's ability to approach the coast rather than its maximum range. Ships only a few hundred yards offshore placed shore positions comfortably inside their supporting-fire envelope. Their heavy batteries could therefore affect the land battle without demanding exceptional long-range accuracy. Keeping the army near the coast multiplied its combat power.