The sacrifice or expenditure must be real and intentional. It must not be a mere destruction and casting off of that which had become already lost and consequently of no value. In Robinson v Price a ship sprang a leak while at sea and was kept afloat only by constant pumping, the pumps being driven by the donkey engine. The coal, which was sufficient for an ordinary voyage, ran short and the ship’s spars and cargo were used for fuel. This was held to be an extraordinary sacrifice. The sacrifice or expenditure must be necessary. Whether the sacrifice or expenditure is necessary rests with the master of the ship. The act must be ordered by the person in control of the vessel. In Papayanni & Teronica v Grampian Steamship Co. Ltd. (1896) a fire broke out on board and the master put into port. The fire increased and the captain of the port gave orders that the ship be scuttled. The master raised no objection as he thought this was in the best interest of ship and cargo. The Court held that the master had sanctioned it and the loss had to be adjusted as a general average sacrifice. The sacrifice must be voluntary. The sacrifice is voluntary even when it is made by order of the port authorities, the master assenting if it was made for the benefit of the ship and cargo. Damage done by smoke and heat alone would not attract a contribution since the fire engendering smoke and heat was not intended. The common danger must not arise through any default for which the interest claiming a general average contribution is liable in law. If the fault was something which constitutes an actionable fault, general average contributions cannot be recovered. A shipowner cannot claim contributions where he allowed a vessel to sail with smoke in her holds or where she was unseaworthy on sailing. However in Greenshields, Cowie & Co. v  Stephens & Sons (1908) a cargo of coal caught fire from the spontaneous combustion of coal. The shippers were held to be entitled to general average contributions from the shipowners in respect of damage to the coal in extinguishing the fire. There had been no negligence on the part of the shippers and it was assumed that both parties were familiar with the liability of coal to spontaneous combustion.