Simrad AUTOPILOT SYSTEM AP50 - Manual (Page 86)

Simrad AP50 Autopilot
84
20221032B
Final check
After installation, the cable glands must be sealed with silicon to
prevent water from seeping in. Also apply silicon grease to the
gasket between the bottom and top cover.
On the inside of the feedback unit cover, a piece of moisture
protecting sponge is attached. The sponge produces a corrosion
preventive gas, and to increase the efficiency of the gas the
cover must be kept tight.