Gunnage

For being set afloat again, after swimming all night and half a day, he brought into the Portland Roads a Crappo ship of twice his tonnage, and three times his gunnage; and now his sailors were delighted, having hope of prize-money.

Source: wiktionary

What winds blew, and how many knots we ran, are all noted down, no doubt, in the ship's log: and as for what ships we saw—every one of them with their gunnage, tonnage, their nation, their direction whither they were bound—were not these all noted down with surprising ingenuity and precision by the lieutenant, at a family desk at which he sat every night, before a great paper elegantly and mysteriously ruled off with his large ruler?

Source: wiktionary

The gunnage shown does not necessarily mean that a ship had that exact number of guns; gunnage was an administrative formula for the computation of the size of the crew.

Source: wiktionary

Now Sir, if you look back you'll find the Number of Guns exactly agree with the Gunnage here payd; and that after the passing his Accounts and deducting his own share, he gave them a Note for 300 l, which being divided as the Act directs, there is coming to the King about 84 l.

Source: wiktionary