We were off of Coronado right in front of the Hotel Del, racing back and forth toward the Point and saw that thing approach from quite a way off... as it came in toward the entrance buoys, it was proceeded by several small boats with quite loud sirens. Pretty hard to not be aware of... guess they don't want it to be a secret or anything.

I believe it is an LCAC... Landing Craft Air Cushion.

I remember years and years ago when the Pegasus used to go in and out of the bay... it was a high speed hydrofoil.

Where did it go when it came into the bay? (did see it leave a short time later) And isn't this "Fleet Week" in San Diego? http://www.fleetweeksandiego.org/events.html