There must be a saving of the imperilled property through the sacrifice. In Pirie v Middle Dock Co. (1881) a ship and cargo were in immediate danger of total destruction by fire which had been caused by the spontaneous combustion of a cargo of coal shipped by the shippers. By jettison of the cargo and pouring water on it and discharging it at a port of refuge the ship and a large part of the cargo was saved. However it was impossible to carry the cargo to its destination and it was sold. The Court held that the shipowners were entitled to a general average contribution from the cargo. Sacrifices of cargo, ship and tackle or freight may give rise to a claim for general average contribution. The commonest instance of a general average is jettison. The cargo jettisoned must have been stowed in a proper place. It should not have been stowed on deck so that, in the absence of special custom, the owner of deck cargo has no claim for contribution if it is jettisoned. If the goods are stowed on deck without the shippers’ consent and they are jettisoned the shipowner will be liable for such a jettison as a breach of his contract to carry safely. Ship and/or tackle – Sacrifice of ship machinery or tackle necessary for the safety of the whole adventure and not incurred in carrying out the shipowners’ original contract will give rise to a general average contribution. All ordinary losses sustained by the ship must be borne by the shipowner. However loss of the ship’s tackle through using it for unusual purposes in order to secure her safety will be the subject of a general average contribution. Where spars were cut up for fuel to keep a pump going, their value was held to be the subject of contribution because this was not the use for which they were intended and the ship would have gone down if the pumping had not been maintained. If the ship is in danger of sinking and the master deliberately runs her ashore to save the cargo and probably the ship, the loss of or damage to the ship is probably a general average sacrifice.