A voluntary departure, without necessity, or any reasonable cause, from the regular and usual course of the voyage insured.
From the moment this happens, the voyage is changed, the contract determined, and the insurer discharged from all subsequent responsibility. By the contract, the insurer only runs the risk of the contract agreed upon, and no other; and it is, therefore, a condition implied in the policy, that the ship shall proceed to her port of destination by the. shortest and safest course, and on no account to deviate from that course, but in cases of necessity.
The effect of a deviation is not to vitiate or avoid the policy, but only to determine the liability of the underwriters from the time of the deviation. If, therefore, the ship or goods, after the voyage has commenced, receive damage, then the ship deviates, and afterwards a loss happen, there, though the insurer is discharged from the time of the deviation, and is not answerable for the subsequent loss, yet he is bound to make good the damage sustained previous to the deviation.
But though he is thus disebarged from subsequent responsibility, he is entitled to retain the whole premium.
What amounts to a deviation is not easily defined, but a departure from the usual course of the voyage, or remaining at places where the ship is authorized to touch, longer than necessary, or doing there what the insured is not authorized to do; as, if the ship have merely liberty to touch at a point, and the insured stay there to trade, or break bulk, it is a deviation. By the course of the voyage is not meant the shortest course the ship can take from her port of departure to her port of destination, but the regular and customary track, if such there be, which long us usage has proved to be the safest and most convenient.
A deviation that will discharge the insurer, must be a voluntary departure from the usual course of the voyage insured, and not warranted by any necessity. If a deviation can be justified by necessity, it will not affect the contract; and necessity will justify a deviation, though it proceed from a cause not insured against. The cases of necessity which are most frequently adduced to justify a departure from the direct or usual course of the voyage, are: 1. Stress of weather; 2. The want of necessary repairs; 3. Joining convoy; 4. Succouring ships in distress; 5. Avoiding capture or detention; 6. Sickness of the master or mariner; 7. Mutiny of the crew.
Contracts. When a plan has been adopted for a building, and in the progress of the work a change has been made from the original plan, the change is called a deviation.
When the contract is to build a house according to the original plan, and a deviation takes place, the contract shall be traced as far as possible, and the additions, if any have been made, shall be paid for according to the usual rate of charging.
The Civil Code of Louisiana provides, that when an architect or other workman has undertaken the building of a house by the job, according to a plot agreed on between him and the owner of the ground, he cannot claim an increase of the price agreed on, on the plea of the original plot having been changed and extended, unless he can prove that such changes have been made in compliance with the wishes of the proprietor.