Joinville's steam battle fleet and the cost of HMS Terrible

The Prince de Joinville advocated a steam battle fleet in European waters, with sailing frigates protecting French interests farther afield. A shift away from sailing ships of the line offered France a possible way to overcome Britain's established numerical advantage. His argument emphasized armed British steamers and French ships under construction when presenting a more favorable balance. He also claimed that four paddle steamers could operate for the annual cost of a 74-gun ship of the line. Britain's HMS Terrible showed the difficulties: the large paddle steamer cost 94,650 pounds to build, consumed substantial coal and carried only 19 guns because paddle boxes occupied so much of the broadside. Britain consequently used paddle steamers as towing partners for sailing battleships, and by 1847 its thirteen ships of the line in European waters each had such an escort.