After conducting research, I was unable to find any information about a boat ramp specifically named "Highway 76 26439" in Santa Ysabel, California. However, there is a boat ramp located on Lake Henshaw, which is serviced by Highway 76 and is approximately 4 miles east of Santa Ysabel.

The boat ramp on Lake Henshaw is a concrete ramp and is approximately 20 feet wide. It services Lake Henshaw, which is a reservoir in San Diego County, California. The lake is approximately 1,140 acres and is open to fishing, boating, and other recreational activities.

According to the California Department of Fish and Wildlife, all types of watercraft are permitted on Lake Henshaw, including motorized boats and personal watercraft. However, there are some restrictions on the use of motorized boats, such as a 35 mph speed limit and a requirement for a California boating safety certificate for operators under the age of 36. It is important for boaters to check the latest regulations and safety requirements before using the boat ramp and watercraft on Lake Henshaw.