Maintenance

Disassembly Warning

Subsonus requires special tools to be disassembled. The only part of Subsonus which can be temporarily removed and replaced in the field for the purpose of cleaning is the white protective cage. Please see Removal and Replacement of Cage for instructions on how to do this. No other parts of Subsonus should be disassembled.

The electrical connector and blanking cap covering the alternate connector port of Subsonus must never be unscrewed. Attempting to do this will cause permanent damage to internal components.

Inspections

The following inspections should be performed prior to deployment and after retrieval.

Damage

Inspect the titanium base and protective cage for deep scratches and cracks. Inspect the blue hydrophone array for any cuts, gouges or damage. In the event of any damage, please email a photo to support@advancednavigation.com for advice before deployment.

Connectors

The connectors and cables should be inspected for damage and checked to ensure they are fully mated.

Every time the connectors are un-mated the inside should be inspected for debris, bent or damaged pins and cracked or damaged rubber. Silicon lubricant such as Dow Corning Molykote 111 should be applied to the male pins and the female socket prior to re-mating.

Biofouling

Inspect for biofouling such as barnacles and other marine growth. Follow the service procedures in Cleaning for removal of biofouling.

Cleaning

Soft marine growth should be gently removed using a soft bristled brush and soapy water. If hard marine growth such as barnacles have attached to the hydrophone array they should not be pulled off with force as this may permanently damage the molded surface.

The recommended way to remove hard marine growth it is to soak the unit in a weak solution (8-10%) of Sulphamic acid. An example product containing Sulphamic acid is Lime-A-Way thick gel. Once the acid has softened the growth it should fall away when brushed down. Strong acids should not be used to remove biofouling as this can cause surface damage to the plastics. If the growth cannot be easily removed the unit should be returned to the factory.

Removal and Replacement of Cage

The white protective cage covering the Subsonus hydrophone array may be temporarily removed to assist with cleaning. The steps are as follows:

  1. Use a 2.5mm hexagonal bit to unscrew the 8 visible fasteners around the cage perimeter.

  2. Gently separate the cage from Subsonus by lifting it away from the hydrophone array.

  3. Inspect the hydrophone array and interior surface of the cage, clean as required.

  4. Replace cage, torque the fasteners to 0.3±0.05 Nm.

Never leave Subsonus with the cage removed. The cage is a critical component required to ensure the hydrophone array is protected from impacts and surface damage.

Factory Service and Calibration

Subsonus should be sent back to Advanced Navigation for servicing and calibration verification every 2 years. At this time the unit will be thoroughly checked and tested, all the seals will be replaced and the factory calibration will be checked and updated if necessary.