We trice our puddings...by and large - S. Maturin in "The Ionian Mission."

One of the great jokes in all of O'Brians novels came when Stephen Maturin, "practised" (made sport of) upon a fellow ship mate, a professor named Graham.  As they were talking Graham decried, "the nautical mind" which Stephen promptly defended by choosing a "faux ami" to put the pompous Graham in his place. So Stephen used this phrase to talk about "pudding."

"Puddings. We trice'em athwart the starboard gumbrils, when sailing by and large."

Proud of his new nautical knowledge, Graham repeated it at dinner.  Of course this shocked the whole wardroom with whom he was dining, and actually eating a pudding called 'spotted dog,' The saying brought a priceless response from them.

"Graham's surprise was nothing to that of the wardroom:

'By and large?' they said. 'Gumbrils' starboard gumbrils?' Jack's spotted dog hung in his gullet for a moment before he understood that someone had been practising upon the professor's credulity, an ancient naval form of wit, played off many and many a time on newly-joined young gentlemen, on himself long, long ago and by Pullings and Mowett on Dr Maturin in former years: but never to his knowledge on any man of Graham's eminence.

"Puddings we have sir,' he said swallowing his own, 'and plenty of them. There is a wreath of yarns tapering toward the ends and grafted all over that we clap about the fore and main masts just below the trusses before we go into action, to prevent the yards from falling; then there is a pudding on the boat's stem, to act as a fender; and the puddings we lay round the anchor rings to stop them chafing. But as for gumbrils, why I am afraid someone must have been practising on you. They do not exist.'

The words were scarcely out of his mouth before he wished them back: he knew Stephen extremely well, and that detached dreamy expression could only mean a consciousness of guilt.

'Unless,' added quickly 'it is some archaic term. Yes, I rather think...'

"But is was too late. Captain Harris, the Marine, was already explaining by and large. With a piece of fresh Gibralter bread and arrows drawn with wine, he showed the ship lying as close as possible to the breeze: '... and this is sailing by the wind or as sailors saying in the jargon, on a bowline; whereas large is when it blows not indeed quite from behind but say over a quarter like this.'

'Far enough abaft of the beam that the studdingsails will set,' said Whiting.

'So as you see,' continued Harris, it is quite impossible to sail both by and large at the same time. It is a contradiction in terms.' the expression pleased him and he repeated , 'A contradiction in terms.'

'We do say by and large, said Jack. 'We say a ship sails well by and large when she will both lie close when the wind is scant and run fast when it is free. No that is what your informant meant.'

'I think not, sir,' said Graham. 'I think you first supposition was correct. I have been practised upon. I am content. I shall say not more.'