SonTek/YSI Argonaut-XR Technical Manual - HydroScientific West

6.9. Protection from Biological Fouling
Argonaut Operation Manual Firmware Version 7.9 (May 1, 2001)
SonTek/YSI
The Argonaut has excellent resistance to biological fouling and can operate reliably even with
biological growth on the transducers. Biological growth causes a loss in signal strength, but does
not affect velocity measurements.
Both the transducers and the underwater housings can be coated with commercial anti-fouling
paints to prevent biological growth. Thick layers of anti-fouling paint on the transducers will
cause a decrease in acoustic signal strength and will reduce the effective measurement range of
the Argonaut. However, for most applications the loss of signal strength caused by anti-fouling
paint does not have a significant effect on instrument performance.
Within the United States, we recommend using an anti-fouling paint called Interlux Tri-Lux II on
all areas except for the transducer of deep-water titanium Argonaut MD systems. This paint
contains a biocide, a copper derivative, which allows its use on all metals. For information on
Interlux paints, contact:
Courtaulds Coatings Phone (908) 686-1300
2270 Morris Avenue Fax (908) 686-8545
Union, NJ 07083 USA
Normal anti-fouling paints, which use coprous oxide based biocides, cannot be used on some
metals as they cause galvanic corrosion. Outside the United States, anti-fouling paints containing
TBT can be used on metal systems with a suitable primer. On plastic systems, any type of antifouling
paint can be used.
IMPORTANT: For deep-water Argonaut MD transducers (encapsulated in urethane instead of
epoxy) use only an anti-fouling paint approved for urethane transducers. These special types of
paints are available from marine supply stores. One suitable paint is MDR Transducer Anti-
Fouling Paint available from West Marine (contact information is below).
West Marine Phone (800) 538-0775 / (408) 728-4430
P.O. Box 50050 Fax (408) 728-4360
Watsonville, CA 95077 USA
When painting metal housings, a suitable conversion layer must be applied to the metal for
adhesion and to isolate the metal from the anti-fouling paint. We suggest Interlux 360
Underwater Metal Primer. The primer should be applied to all exposed metal surfaces except
sacrificial zinc anodes. Apply the anti-fouling paint to all surfaces of the instrument that require
protection. Follow the instructions on the paint container with the following exceptions.
• Apply only one coat of anti-fouling paint to the transducers. Each layer of paint will cause
some loss in signal strength and multiple layers can potentially affect system performance.
Ensure that the paint has a smooth, even surface with no air bubbles.
• CAUTION: Do not paint the sacrificial zinc anode. Doing so will remove all corrosion
protection.
If anti-fouling protection is desired for some portion of the cable, the paint can be applied
directly to the polyurethane jacket without primer.
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