Two torpedo boats, the Azor and Halcon (length 135 feet, beam 14 feet; trial speeds Azor 24 knots, Halcon 23.5 knots) fitted with 1550 indicated horsepower inverted-vertical triple-expansion condensing marine engines with steam supplied by a single large marine locomotive boiler; were built by Messrs. Yarrow and Co., Poplar, for the Spanish Government. The construction of the hulls of these two boats was much stronger than normally used in torpedo boats as strength for actual service had often been injudiciously sacrificed to obtain exceptional speeds. It was felt that in future naval authorities would be ready and willing to sacrifice a little speed in order to obtain more reliable vessels. The same also applied to machinery, which at that time was only capable of being operated successfully by men of exceptional training, who at times of war would not be readily available.