Z. Roberts meter, Mod. 3 



3. Low velocity types 

 a. Hytech 



b. Crouse-Hindes 



c. Pruitt 



d. CM -3 (Japanese) 



Geomagnetic electro- 

 kinetograph (ONR) 



Photographic type of current meter 

 (German paddle wheel) 



Parachute drouges 



Speed: 0. 2 to 7.0 knots. 

 Accuracy: ±0.1 knot. 

 Direction: to 360°. 

 Accuracy: ± 10 . 



Speed: 0. 1 to 7.0 knots. 

 Accuracy: ±0. 1 knot. 

 Direction: to 360 . 

 Accuracy: * 10 . 



Speed: 0. 1 to 7. knots. 

 Accuracy: * 0. 1 knot. 

 Direction: to 360 . 

 Accuracy: ± 10°. 



Speed: 0. 04 to 7. knots. 

 Accuracy: *0.01 knot. 

 Direction: to 360°. 

 Accuracy: * 10 . 



Speed: 0.2 to 5.0 knots. 

 Accuracy: * 0. 1 knot. 

 Direction: to 360°. 

 Accuracy: ±10°. 



Uncertain. 



Speed: 0.3 to 3.0 knots. 

 Accuracy: *0. 1 knot. 

 Direction: to 360°. 

 Accuracy: * 10 . 



Speeds and accuracies deter- 

 mined from tow tests by the 

 Hydrographic Office. 



WAVE HEIGHT 



Bottom pressure instruments 



Wiancko pressure measuring 

 system (U.S. Navy Mine Defense 

 Laboratory) 



Depth: up to 200 ft. Senses 

 changes in water height of 

 0. 1 to 80.0 in. 



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