OK, I had an idea for this for awhile and finally decided to test it. There is a parameter accessible in Tower called ' Arming Check ' This can disable the pre-arm checks that are used before arming. As you will see below, just certain sensors can be disabled or all of them. I simply disabled them since this is just for the pre-arm check not disabled during flight. I was able to simulate being on a boat and able to arm and take off in manual mode. By using Tower during flight, you can also use the RTH option of 'Return To Me' instead of the usual RTH. This would get the Solo back over head if needed if the boat has changed positions during flight.
This should be of use to the 'Boat People' as well as other situations when you need to arm on an less than level surface. This also disables the Compass check, which I believe is how 3DR took off from the hood of that pickup in one of their latest videos.
As is the rule for anytime you modify parameters, extreme caution is needed that you know what you are modifying, and could result in voiding the warranty if the changed parameter contributed to a crash. It would also be prudent to pre-fly the Solo before getting on the boat to be sure everything else is working as it should. But if I were on a boat, I would have no problem giving it a try. YMMV..
Arming check (ArduCopter:ARMING_CHECK)
Allows enabling or disabling of pre-arming checks of receiver, accelerometer, barometer, compass and GPS
VALUE MEANING
0 Disabled
1 Enabled
-3 Skip Baro
-5 Skip Compass
-9 Skip GPS
-17 Skip INS
-33 Skip Params/Sonar
-65 Skip RC
127 Skip Voltage
@Captain J.D. , let us know if this works for you.