Going to San Clemente Island is not like going to Catalina.
Weather & sea conditions are rougher out there.
Here is some info.
Safety Zone Procedures
Effective June 21, 2010, a 3nm Safety Zone will exist around San Clemente Island. Extending from the high tide line out to 3nm, the Safety Zone is divided into eight sections (Figure 1).
Figure 1. San Clemente Island Safety Zones
Unless scheduled for hazardous military training and testing activities, six sections (A, B, C, D, E, F) are available to the public for recreational and commercial activities (e.g. fishing, diving, sailing). Check the Schedule/Safety Zones
link for the daily status of these six safety zone sections. An area not highlighted is not scheduled for hazardous military operations, so the public may access these offshore waters. If an area is highlighted in red, hazardous military operations are scheduled for the entire day, so do not enter that area at any time during the day in question. If an area is highlighted in red/green stripes, the area is scheduled for part of the day for hazardous military operations, so do not enter these areas during the scheduled period; see the tables to the left of the map on that page.