minimum specifications: Drifters shall be built according to the stated principles of construction in the "SVP Drifter Construction Manual" (Sybrandy, A.L. and P.P. Niiler (1991): "WOCE/TOGA Lagrangian Drifter Construction Manual". Scripps Institution of Oceanography, SIO Reference 91/6.58pp., and updated in 1995, DBCP Tech Document Number 4). Drifters must use the ARGOS system to send data using a 90-second repetition rate, with a 100% duty cycle. The transmission power to ARGOS should be 1 watt or less. The Drifters shall have Sea Surface Temperature, Submergence and Battery Voltage Sensors (see "WOCE/TOGA Lagrangian Drifter Construction Manual" for complete specifications of all sensors, drogue, transmitter and drifter general construction guidelines); Drifters shall be built with a holey-sock "Mini-Drogue" that is a smaller (60cm diameter) version of the drogue specified in the "WOCE/TOGA Lagrangian Drifter Construction Manual". The length of the "Minim-Drogue" shall be chosen so that the drag-area-ratio of the complete drifter system shall be not less than 40. The specific construction technique has to have a proven history of deployment at sea. "Proven history" shall consist of 10 holey-sock drifters, transmitting for over 180 days without drogue loss. Drifters shall use a "Mini-Drogue" with its deployed vertical center at 15 meters depth. Specific "Mini-Drogue" materials and construction specifications: a) The holey-sock should be made from fray resistant nylon clothe; diameter 60-63 cm, length computed to provide a drag-area-ratio of 40 or larger. The holey-sock shall have at least three segments with supporting circular framing sewn into place. Each segment shall have two pairs of 30cm diameter opposing holes, offset by 90 degrees from each other. Drogue is centered at 15 m depth. b) Inert ballast material shall be inserted into the lowest ring of the "Mini-Drogue" of sufficient weight that a net tension of 1.5-2.0 kg will be exerted by the tether on the surface float. c) Rings made of hollow sea-water resistant, plastic tubing shall be used as the circular supporting framework for the drogue. These shall be drilled to allow flooding d) Attachment bridle of the drogue shall consist of hub and at least 4 spokes of 0.32 diameter polypropylene-impregnated wire rope radials, positively attached and epoxy-restrained at hub to tether from surface float. Radials attach to top PVC ring using abrasions resistant cushions fixed at 60 - 90 degrees spacing. 10 cm-long rubber air hose carroting fitted where radial enter hub. Attachment point of tether to hub covered with a minimum of 15 cm long polyurethane carrot. E) The tether from the drogue to the float shall be at least 0.32 cm in diameter made of polypropylene-impregnated wire rope. There shall be no sub-surface float attached to the tether. The carrot to the spherical surface float shall be at least 15 cm long. 6. SHIPPING CONTAINER: The shipping container should be double walled container measuring less than 43" * 43" *43" cube capable of domestic and international air, land or sea transport. Container should allow easy access for inspection and testing of instrumentation and ARGOS telemetry system at the point of delivery. Containers and closures shall comply with the interstate Commerce Commission regulations, uniform Freight Classification Rules, or regulations of other carriers as applicable to the mode of transportation. Individual Drifters should be configured so that deployment from Volunteer Observing Ships can be readily done without changing the shipping configuration. The tether should be wrapped and taped with water-soluble tape around a water-soluble cardboard tube that should be left in place for deployment to prevent tangling. The drogue should be wrapped with water-soluble paper tape that should be left on the drogue upon deployment. The tape should dissolve quickly once the drifter has been deployed, allowing for an orderly release of the drogue. Instructions for deployment should be attached to the outside of each unit. Contractor shall complete the attached specification sheet and submit to Global Drifter Center before a GBL is issued. Specification sheets should list individual ARGOS ID of each buoy produced and provides calibrations and message format information. 7) RELIABILITY CLAUSE - Drifter transmission power should last on average a minimum of 365 days. A new "Specifications Sheet" must accompany any modification that is made if a buoy is found defective and is returned to the manufacturer for repair. Manufacturer should cover shipping costs for any returned defective drifters. Revised Specification sheets must be provided before drifting buoys are reshipped. Specification sheets should list individual ARGOS ID of each buoy produced and provide calibrations and message format information. SVP SPECIFICATION SHEET (SVP3, MINI-DROGUED) VERSION MODIFIED 28 OCT 2002: ARGOS ID(s); Manufacturer; Sensor Array SVP; Surface Float Description; Tether description; Drogue description; Drogue depth; Drogue Length; Cross-sectional area above drogue; Cross-sectional area of the drogue; Transmitter type; Transmitter manufacturer; Controller manufacturer; duty cycle continuous; Message length 32 bits; Message format; Observation cycle 15 minutes; Repetition rate 90 seconds; Power Supply; Antifouling; Battery voltage sensor; Battery voltage equation; Temperature sensor type (include manufacturer and model); Temperature equation; Drogue sensor type; Submergence equation; Salinity Sensor Type (include manufacturer and model); Salinity Equation; Barometer type; BP equation; Wind Speed Sensor Type (include manufacturer and model) Wind Speed Equations; Wind Direction Sensor Type (include manufacturer and model) Wind Direction Equations; GPS Type (include manufacturer and model); GPS Equations; Additional Sensor Types (include manufacturer and model); Additional sensor equations; Shipping container and Comments. Questions should be addressed to Jean Jennings at 816-426-7456 x238.
 

For further information contact: James.Manning@noaa.gov

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(File Modified Jun. 21 2006)