Mixer for SITL boat
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Throttle of left propeller of boat on Output 0
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M: 2
S: 0 2    10000   10000      0  -10000  10000
S: 0 3    10000   10000      0  -10000  10000


Throttle of right propeller of boat on Output 1
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M: 2
S: 0 2   -10000  -10000      0  -10000  10000
S: 0 3    10000   10000      0  -10000  10000