The road from Bridgend to Bruichladdich follows the edge of Loch Indaal. Pull off onto the grass just before the little hill into Blackrock - the track is obvious.
Loch Indaal is a large sea inlet so is sheltered and quite flat. There is very little in the way of beach with Blackrock/Bridgend being the largest areas of sand for launching/landing. A trip across the water to Bowmore is fun in the right direction!