Battling Slavers Off The West Coast of Africa

ONE of the best storytellers afloat sets sail again in the pages of ''The Commodore.'' This 17th novel in Patrick O'Brian's series about adventure in the British Royal Navy is as finely trimmed as the ships he writes about.

The legion of fans who have savored the unfolding story of Captain ''Lucky Jack'' Aubrey and the saturnine Dr. Steven Maturin can be of good cheer. The old master hasn't lost his touch.

Last year's ''Wine Dark Sea'' was a grand melodrama, filled with storms, sea chases, and climactic battles. A first-time reader might do well to start with that volume, then return to the beginning of the series, with ''Master and Commander'' (1969) and ''Post Captain'' (1972).

This year's offering is in a lower key. The focus is on character, not incident, and the social byplay of life ashore and in the closed world of the ships of the British fleet during the last years of the Napoleonic wars.

As the novel opens, the two friends are returning from the circumnavigation that has occupied the last few books. Both are immensely wealthy from this and previous voyages -- the reader's familiarity with the prize system (and much else) in the 19th-century British Navy is assumed.

Their return home gives the author a chance to demonstrate his gift for good humored social satire, with finely drawn characters in settings ranging from the Admiralty to Jack's country home. The flavor is not so much of Jane Austen, as it was in the early works of the series, but Dickensian.

Jack is eager to return to command. He is delighted at the opportunity to fit out a squadron to proceed against the slaver of the Bight of Benin, a bay on the West African Coast. Jack's friend and companion, Dr. Maturin, is to go along as expedition surgeon.

Felicitously, for the narrative at least, Maturin's old enemies are afoot again, and it is expedient for him to leave the country for a while. This voyage is doubly opportune. Not only does it give him the cover to spirit away his boxes of treasure to safekeeping in a castle in Spain, but it will give him a chance to indulge in his passion for natural history and collecting.

Nevertheless, this is a curious sort of adventure story. There is not much dramatic tension; the clash of battle is mostly told, as in Attic tragedy, by messengers from off stage. During the expedition against the African coast slavers, Aubrey, as commodore of his little fleet, is out of sight of land for most of the events.

Maturin is frantic with eagerness to get ashore to see the exotic flora and fauna, but the fear of fever keeps the crew to their ships. He does make it to shore long enough to make the acquaintance of a handsome lady naturalist.

A good adventure story takes us away to exotic locales and situations that we would hardly wish to experience personally. Raiding the slave ships of the fever-plagued West African Coast was grim business. But to go beyond armchair adventuring, the story must return us wiser.

Much of the appeal of the Aubrey-Maturin novels is that they are so rich in humor and invention. They are filled with courage and treachery, faith and greed, and above all love -- the love between men and women, between parent and child, and between men and men. Their author delicately and sensitively details the bonds that join these two friends through their adventure together. One cannot help liking them too and wishing them success in their exploits.

The appearance of a new work in the series is always cause for rejoicing. It can only be hoped that the future will continue to offer some new voyage to remote lands and exotic adventures.