Simrad MTW datagram format
Simrad MTW is a proprietary datagram format created by Kongsberg Maritime to provide the water temperature measured by the trawl sensor.
Format
$IIMTW,xx.x,C<CR><LF>
Description
1 IITalker identifier
2 MTWDatagram identifier
3 xx.x,CWater temperature (DegreesCelsius)