Disabling alarm system

[camembert]

Every time I take my S-Max on a ferry (which I do fairly frequently) the alarm system is set off by the ship's motion.
I can't see from the user handbook how to lock the car without enabling the alarm system. I have tried locking the car using the keys rather than the blipper but it still gets triggered.
Worth noting that several hundred other vehicles do exactly the same on each crossing. Unnecessary noise and battery drain.
How can I do this?

[gregers]

iirc you can set the alarm within the on board settings.

[mike wilson]

I have to double click the fob to deadlock and set the alarm.  One click locks.

Same with key.  You have to turn it two ways to deadlock and set the alarm.