Mooring Information

The KEO mooring design is based on the prototype TAO moorings in the tropical Pacific modified for the harsh conditions in the Kuroshio Extension region.

The KEO mooring is a slack mooring with scope 1.40 because of the severe current regime. The upper portion of the mooring is kept fairly vertical (but less so than taut-line moorings) by using a reverse catenary design. Because the mooring line is larger than the ocean depth, the subsurface pressure data should be used to remap the observations onto nominal depths. With a watch circle radius of approximately 6 km, mariners are asked to keep a safe distance from the mooring.

The surface buoy is a 2.3 m diameter fiberglass-over-foam toroid with center hole glassed over. It has an aluminum tower and a stainless steel bridle with load cell to measure tension of the mooring. When completely rigged, the system has an air weight of approximately 660 kg, a net buoyancy of nearly 2300 kg, and an overall height of 4.9 m. The electronics tube is approximately 1.5 m long, 0.18 m diameter, and weighs 27 kg. The buoy can be seen on radar from 4-8 miles depending on sea conditions.

Non-rotating 3/8" (0.92 cm) diameter wire rope jacketed to 1/2" (1.27 cm) is used in the upper 700 meters to guard against damage from fish bite. Plaited 8-strand 3/4" (1.9 cm) diameter nylon line is used for the next 4900m of the mooring, spliced to 2280m of buoyant polyolefin mooring line. The anchor was fabricated from scrap railroad wheels, and weighs 3100kg. All hardware is standard equipment as used in other PMEL moorings and deployments follow the traditional anchor last routine.

As with TAO mooring systems, the subsurface sensors clamp onto the wire rope strength member that serves as the inductive element. Addressable modules on the cable allow the system to be expanded for new sensors by adding the appropriate hardware and software interfaces. Flexibility in the design also allows the interface of additional sensors including barometric pressure and ocean currents. Most measurements are made at a sample rate of 10 minutes, with the exception of short-wave and long-wave radiation (2 minutes), and rainfall (1 minute). These high temporal resolution data are recorded internally and available after mooring recovery.

Diagram of KEO-3, May 2006 - May 2007
Diagram of KEO-2, June 2005 - Nov 2005
Diagram of KEO-1, June 2004 - June 2005
Instruments, June 2004 - June 2005

Gallery of instruments and details intended to facilitate recovery of mooring (Nov, 2005)