OFS Drop keel datagram format
The proprietary OFS datagram contains the current length travelled by the drop keel. The information is required to establish the offset of the transducer face relative to the vessel origin. A custom-built sensor may be required for this measurement.
Format
$KMOFS,xx.xx, *hh
Description
The travelled length is measured as an offset value from the ship origin.
•  KM: Talker identifier
•  OFS: Datagram identifier
•  xx.xx: Depth (Metres)
•  *hh: Checksum