DIGITAL ENGINEERING - Sonar Dome Anti-Fouling Tracking and Prediction Tool

Marine fouling has always been a significant maintenance problem.  If the fouling is left untreated, fuel costs increase and maneuverability is reduced. The ship must be docked and cleaned to remove fouling and this increases maintenance costs and reduces availability. To control fouling, the hull and other components below the water line can be coated or imbued with anti-fouling treatments.  Active anti-fouling treatments slowly leech biocide to prevent fouling from occurring on the hull or component of the ship. The treatments must periodically be reapplied, or an impregnated component must be replaced.  Prevention of fouling on sonar domes is especially critical. If fouling builds up on the dome, then both the function of the sonar and the acoustic signature of the ship are compromised. Currently all the US Navy Arleigh Burke Class Destroyers and Ticonderoga Class Cruisers use Collins Aerospace’s sonar dome rubber window (SDRW) that is manufactured using NOFOUL® Rubber. These sonar domes are imbued with tributyltin oxide (TBTO) during the manufacturing process and replaced when the TBTO is depleted. The Naval Research Laboratory (NRL) recently developed a non-destructive method to measure the amount of TBTO remaining in a SDRW. This technique provides data for a more detailed understanding of the remaining anti-fouling capacity. The next step is to centralize and organize this information together with other relevant parameters related to the SDRW service life.  Luna Labs will develop Tributyltin Oxide Prediction Application (TOPA) software to organize, store, and analyze the SDRW related data. TOPA users will access details about sonar domes including manufacturing information and TBTO measurements that are combined with maintenance information and historical ship conditions. This data will be used as inputs for a physics-based diffusion model. The main objectives of the Phase II effort are 1) Refine software to create, organize, and display anti-fouling properties of sonar dome rubber windows. 2) Refine predictive model for TBTO in sonar dome rubber windows. 3) Implement software into Navy enterprise systems. The main tasks of the work are to complete development of the software, determine a TBTO mass diffusion model and perform experimental work on the NOFOUL® rubber to further understand the variables that affect the diffusion.