CA Ins Code Section 1943

A deviation is proper:

(a)

When caused by circumstances over which neither the master nor the owner of the ship has any control.

(b)

When necessary to comply with a warranty, or to avoid a peril, whether or not the peril is insured against.

(c)

When made in good faith and upon reasonable grounds of belief in its necessity to avoid a peril.

(d)

When made in good faith, for the purpose of saving human life or relieving another vessel in distress.