Trafalgar seems to be the event at which specific ricochets are described:
Lieutenant des Touches, on board the Intrépide, later summed up the differences between the British gunners and those in the French and Spanish ships:
At that time our principle was to aim at the masts, and in order to produce any real damage, we wasted a mass of missiles that, fired into the hull of the enemy vessel, would have brought down part of the crew. ... the English, who fired horizontally and reached us through our wooden sides... [The English] used ... a horizontal fire, thanks to which, if they did not score a direct hit, they at least obtained a very effective ricochet.
The first specific mention of trials for ricochet are mentioned as in the early 19th century:
Ricochet was used in the 18th and 19th centuries as a technique for attacking ships with cannon balls ... The advantages of firing a cannon at small elevations above the horizontal as a technique in the naval warfare of the early 19th century have been described in detail by Sir Howard Douglas. ...
Within a range of about 600 yards, ricochet could be used to considerable effect and even at greater ranges the chances of producing some sort of damage to the target were greatly improved because slight errors in range did not necessarily imply that an enemy ship would be missed completely. Instead of falling short or passing over the top of the ship, the low trajectory and high horizontal component of velocity ensured that some part of the ship (usually the rigging) would be hit and damaged provided that the direction was good and the range sufficiently long. The reduced velocity of the projectile at the target after multiple impact meant that it was unable to penetrate the specially protected sides of a ship, but in carrying away rigging and thus immobilizing a ship it was a sound aggressive tacti. Such was the interest in this tactic that extensive tests were performed with various types of shot from on board H.M.S. ‘Excellent’ in 1838.
—Johnson & Reid, 'RICOCHET OF SPHERES OFF WATER'
The same Sir Howard Douglas is cited in the USN 'Elementary Instruction in Naval Ordnance and Gunnery' from 1862, which writes extensively on ricochet, suggesting most naval officers would have known about the tactic by then:
When balls in ricocheting rebound with a less angle than 7 degrees, their penetrating power is lost. At the end of their flight, they do not rise at any angle, but literally roll on the water, and are then of service only against boats and small craft.
If then the water be smooth, and mere range be the object as in the case of acting against troops or craft, ricochet firing will be perhaps the most effective. But if penetration at the greatest distance be the object, it is best accomplished by resorting to all the elevation of the piece that circumstances will permit; which, as before remarked, in a ship's ports when on an even keel is usually not more than 10 or 12 degrees.
Douglas's 'Naval Gunnery' was first published in 1820.