I just looked at an updated chart and the channel NOW does go to the east of "half-mile rock" just outside the river entrance. (I had written above "Although the charts show the main entrance channel to be west of the large rock at the entrance, I have heard that the deeper water is now to the east of that rock and the channel now runs between it and the beach".)

Well, the updated chart confirms this. If you have outdated charts they may lead you to the wrong side.

In any event, I advise you to skip Westport in a strong southerly or if a big ocean swell is running, as the surf could slam your keel down hard on the bottom. This is "The knubble" at the west side of the entrance.