Origin of "attack burning ships on fire?"

No, but he didn’t get docked for failing his exam (as he was about to do when the attack was announced) either. Later, he was promoted by a captain, as I recall, to Lieutenant, without having to undergo the exam. (Ditto for his captaincy.)

The Hornblower books are great, ripping yarns. I don’t know how historically accurate they are (other than, of course, there was no Horatio Hornblower taking part in significant actions of the Napolonic Wars) but so far as my amateur knowledge extends, are accurate in their details of naval combat and shipboard life of the 18th Century British Navy.

Stranger

When the Spanish Armada came over to invade England (well, they came over to escort a Dutch army to invade, but that’s irrelavent for now) they moored in a harbour on the French coast. Normally, the enemy would small boats on fire into a harbour and the defenders would sit in small boats with large poles and guide them out of the way. Sir Francis Drake sent big ships of the line into the harbour on fire, initially piloted by a crew who got into small boats once the course was in no doubt. The Spanish captains panicked and cut their anchor lines to get away quickly, ensuring chaos.

From what I can recall, not many ships burned in the harbour, but without anchors they were useless as military vessels and took the long way home around Britain.