Boat Camp Mooring Buoy Maintenance Project 
 Emerald Bay State Park

 Prepared by:

 Underwater Science and Educational Resources
 Indiana University Bloomington, Indiana 47405
 January 1996

Authored by:
Charles Beeker, Director
Robert Kessler, Diving Safety Officer
Robert Richardson, Research Assistant

With Contributions from:
Carrie Chism, Dallas Drummond, Greg Lawrence


Picturesque Emerald Bay and adjacent D.L. Bliss State Parks are among the most frequently visited parks managed by the California State Park System. Daily, thousands of people enjoy the beauty of Lake Tahoe from scenic observation points, by State maintained hiking trails, or by boat. To facilitate boat visitation, the California Park System maintains the Boat Camp, located on the north shore of Emerald Bay. Facilities include campsites, restrooms, twenty-two mooring buoys for personal watercraft, and a readily accessible pier.

During the summer of 1995, Indiana University (IU), under contract with the California State Park System, performed maintenance and upgrading to the existing Boat Camp mooring buoy system. The contract (#C943A010) was completed between June 8-16, 1995, by faculty and students from IU's Underwater Science and Educational Resources (USER), a program within the Department of Recreation and Park Administration.

The Emerald Bay State Park Mooring Buoy Maintenance Report was completed by IU to assist the California State Park System in monitoring and future upgrading to the Boat Camp facilities.

As stipulated in the California State Parks Contract (#C943A010), awarded to IU, the primary mission of the Emerald Bay Mooring Buoy Maintenance Project was to upgrade the existing twenty mooring buoys, and the installation of two new buoys in the Boat Camp facilities. The secondary mission of USER was application of the Photographic Imaging Technique (PIT) to the significant underwater resources of Emerald Bay Underwater Park. These included updated photographs of the components of the Emerald Bay Historic Barges for application to the World Wide Web composite site plan, and PIT documentation of the small historic boats located within the Boat Camp mooring field.

      Image of buoy      Image of group       

 Image of group taking measurements      Image of crew in raft

Participation Selection Criteria
IU participants for the Emerald Bay Mooring Buoy Maintenance Project were selected from students in the Underwater Resource Management Certification Program, offered through the IU Department of Recreation and Park Administration. Applications were reviewed by the IU Diving Safety Officer for current university Scientific Diver Certification and demonstrated diving experience in the environmental conditions anticipated to be encountered while diving in Lake Tahoe (Alpine Lake 6,250' elevation). Selected applicants registered for R499 Research (3 credits), as part of their field research experience requirements for the Underwater Resource Management Program. Additional preparation included review of previous IU involvement in the Emerald Bay Barges Archaeological Field Investigation (1989), Emerald Bay Historic Barges Shipwreck Park Project (July 1994, September 1994), and IU development of the Emerald Bay World Wide Web Home Page, in cooperation with the California Department of Parks and Recreation.

Indiana University (IU) and the California State Park System determined the best time to conduct the Emerald Bay Mooring Buoy Maintenance Project was in early June, to enable IU student participation and prior to Emerald Bay State Park peak visitation. Due to the lack of adequate diving logistical support, IU provided an on-site portable compressor; California Parks provided support boats, scuba tanks, and diver weights; and participants provided their personal dive equipment.

To assist IU in determining the best approach to complete the Emerald Bay Mooring Buoy Maintenance Project, Steve Johnson, State Park Ranger, Ed Z'berg - Sugar Pine Point State Park, provided a preliminary assessment of the existing mooring buoy system, and necessary materials for upgrading the system. Based on the computer generated mooring buoy site assessment, John Foster and Jim Barry, California Department of Parks and Recreation, established the primary underwater datums to facilitate subsequent field work.

IU diver teams assessed each component of the existing Boat Camp's twenty mooring buoy systems (buoy ball, mooring ring, down chain, anchor shackle, anchor iron rebar, anchor base), and generated a working site plan for subsequent field work. Along with their personal dive profile, IU dive teams recorded the anchor base type, depth, and extent of buoy system repairs on the master Boat Camp site plan. Following determination of extent of repairs or replacement required for each component, each of the existing twenty mooring buoy systems were upgraded or repaired. Additionally, IU surveyed the immediate area of the Boat Camp mooring field to determine location of existing anchor bases, and best positioning for the installation of two new mooring systems. Utilizing a 1,000 lb lift bag, IU divers repositioned one anchor base to a predetermined position. Utilizing this base, and one additional non-used anchor base, two new mooring buoys were installed.

Although the primary mission of repair and upgrade to the Boat Camp mooring buoy system was completed, due to extreme deterioration of weather conditions the secondary mission for application of the IU developed Photographic Imaging Technique (PIT) was only partially undertaken. Water visibility conditions and time constraints were a problem, however, John Foster and John Freeland were able to utilize a Nikonis V and Hi8 Sony Video System to record components of the Emerald Bay historic barges and two of the historic boats in the boat camp area. These images were used to update the PIT documentation of the Emerald Bay Historic Barges Shipwreck on the World Wide Web.

Recommended Mooring Buoy System
The purpose of a mooring buoy system is to act in place of a deployed anchor for boats visiting a site. Installation of a mooring buoy system must consider factors such as: type and size of vessels utilizing the system; varying environmental conditions including fluctuations in water depth, wind changes, and seasonal changes such as formation of ice; to accomplish the goal of safe mooring for multiple vessels under changing conditions.

Major components of a mooring buoy system include:

  • Mooring Ring or Pick-up Line- facilitates tying boat to system.
  • Buoy ball- provides floatation and surface site identification.
  • Down line- chain or rope to connect buoy to secure anchorage.
  • Anchor Base- block or cemented base to hold system.

For use by recreational boaters in the Emerald Bay State Park, the recommended mooring buoy system consists of a 6" galvanized mooring ring which is quick-linked to a 3/8" galvanized chain; passing through a 24" buoy ball; utilizing a 7/16" shackle, with stainless steel wire wrap, connected to the 3/4" iron rebar; cemented into the approximately 1,500 lb anchor base that has a minimum of three angle iron legs protruding from the bottom into the lake sediment (see Illustration #2). Estimated cost of the recommended system is $263.50, not including anchor base (see Figure #4).

Mooring System Assessment and Repair
The Emerald Bay Mooring Buoy Maintenance Project involved the assessment and repair of the existing twenty mooring buoys and addition of two new complete mooring systems, to enable a mooring capacity of twenty-two boats at the Boat Camp facilities. The mooring systems were arranged in two rows, parallel to the shore. Depths at each of the concrete anchor bases were recorded and a numbering system employed, when possible, with "odd" numbered buoys shoreward, and "even" numbered buoys lakeward (see Illustration #1). Each of the mooring buoy system components were assessed (mooring ring, buoy ball, down chain, anchor shackle, iron rebar, concrete anchor base) and repairs or replacement to components completed for all twenty two systems (see Figure #1). Eleven down chains were completely replaced from buoy ball to the anchor base iron rebar (Buoy #1,2,3,5,9,11,13,14,15,17,20), and eleven down chains were repaired with 5' to 10' of lower section of chain connected to the anchor base and quick-linked to existing down chain (Buoy #4,6,7,8,10,12,16,18,19,21,22). All anchor bases were rectangle-shaped, except the trapezoid-shaped anchor of buoy #3, and a minimum of two barrel-shaped, non-utilized anchor bases (see Illustration #3). All buoy balls were assessed for cuts and flotation, and replaced, if needed.

Diver's Log and Air Requirements
During the six days required to complete the primary mission of the Emerald Bay State Park Boat Camp Mooring Buoy Maintenance Project, a total of 15:24 Working Hours Underwater were compiled by four dive teams (see Figure #2). Note: the total time for each individual member of a dive time was added together to compute their team's daily total working hours underwater. The divers' logged depths varied from the shallowest dives of 14' to a maximum depth of 61'. Due to limitations for safe diving at an elevation of 6,250 for Lake Tahoe, no diver team's total hours underwater exceeded two hours for any single day of diving.

A total of 59 scuba tank fills were required to complete the 15:24 Total Working Hours Underwater for the six day project. Note: partial fills ("top-offs") were combined together to compute the number of tanks filled, as if each tank were completely empty. A Mako 5000 psi Portable 5 cfm Compressor was utilized to fill tanks at the Boat Camp, for a total running time of 14:31 (see Figure #3). Compressor utilization at an altitude of 6,250' results in actual compressor output of approximately 3.2 cfm (cubic feet per minute).


  1. 6" mooring rings and 3/8" quick links be installed on all buoys balls which currently only have a shackle on top, to facilitate tying boat lines to the buoy ball (Buoy #1,3,9,13,19,21,22). This can be accomplished from the surface by use of Park Aids.
  2. The buoy balls be numbered in a logical order to facilitate boat mooring and recording of information on campsite registration forms (see Illustration #1).
  3. The mooring system be inspected periodically for propeller cuts to buoy balls, fluctuations in lake water level, and other factors which would adversely effect safety by patrons using the Boat Camp facilities.
  4. Based on the type of materials used and previous durability of the mooring buoy system, it is not anticipated that the next major upgrade and repair will be necessary for up to five years. However, divers should perform a cursory inspection to the underwater components prior to the beginning of each visitation season.
  5. The PIT be completed for historic boats in the Boat Camp mooring field, providing resource managers a photographic record of the current condition and location of each of the historic boats, and facilitate monitoring and managing of these significant underwater resources.

Beeker, Charles D.
1994 "California Opens Its First Underwater Shipwreck Park,"
Underwater USA Wreck Diver Newsletter, vol. 2 No 6.

1995 "PADI Sponsors California's First Underwater Park," Undersea
Journal, Second Quarter. Santa Ana, CA.

Halas, John
1985 "A Unique Mooring System for Reef Management in the Key Largo
National Marine Sanctuary," Proceedings of the Fifth
International Coral Reef Congress, Vol. 4. Tahiti.

Smith, Sheli O.
1991 Emerald Bay Barges Archaeological Survey 1989-1990, on file,
Los Angeles Maritime Museum. San Pedro, CA.

For Further Reading
1995 "A Divers Guide to D.L. Bliss State Park & Emerald Bay
Underwater State Park," on file; D.L. Bliss State Park.
Tahoma, CA

Paher, Stanley
1994 Destination: Lake Tahoe, the Story Behind the Scenery, KC
Publications, Las Vegas, NV.

Zauner, Phyllis
1982 Lake Tahoe: The Way It Was Then--And Now, Zanel Publications,
Sonoma, CA.

The Emerald Bay Mooring Buoy Maintenance Project of June 1995, and this subsequent document, was made possible through the combined efforts and assistance of numerous organizations and individuals. These include, from the California Park System: Tom Lindsay and Midge Redden, D.L. Bliss State Park, and Robert G. Macomber, District Superintendent, for providing the contracts and administrative assistance; Steve Johnson, State Park Ranger, Ed Z'berg - Sugar Pine Point State Park, for preliminary site assessment and on-site logistical support; John Foster, Senior State Archaeologist, for field work and assistance in the preparation of Boat Camp site plan and editorial review of the Boat Camp Mooring Buoy Maintenance Report; Martin Dyer, Chief Deputy Director of California Parks and Recreation, for site visitation and administrative assistance; and Jim Barry, Senior State Ecologist, for aiding in the establishment of primary datums. Many other individuals donated time, equipment, and expertise, including: Richard Swete and Mitch Marken, Underwater Archaeologists; Richard Adkins, Historian; John Freeland, Audio Visual Coordinator; and Thomas Cross, University of California, Davis Diving Technician. And final thanks to the faculty and students of Indiana University, including: Charles Beeker, Director of Underwater Science and Educational Resources; Robert Kessler, Diving Safety Officer; and Research Assistants Carrie Chism, Dallas Drummond, Greg Lawrence, and Robert Richardson.

To learn more about Emerald Bay State Park visit:
Emerald Bay SP