No, contrary to what you may have heard, Tobias Smollett’s Roderick Ransom is NOT the originating point for modern naval fiction, nor is Homer’s Odyssey, nor Daniel Defoe’s Robinson Crusoe. These works, while having a maritime background, are not informed by naval matters; in most cases, the naval aspects are more of a conveyance rather than an integral part of the narrative. Shipboard life and concerns do not loom large in any of these works. Again, the maritime acts as a backdrop to the main activities of the story; it is not the story itself. They are written by landsmen looking out to the sea.
Primacy of position as to the “Father of Naval Fiction” goes undoubtedly to James Fenimore Cooper (yes, he of the Leatherstocking Tales featuring the intrepid Natty Bumppo) who published The Pilot in 1823 (at least one source lists the date as 1824); he was followed by Marryat (portrait here; brief but informative biography here) with the first of his many nautical works – The naval officer; or Scenes and adventures in the life of Frank Mildmay (usually referred to as “Frank Mildmay”; 3 vols., 1829). (N.B. Many British novels of the 19th century were written in three volumes; come here for an explanantion.) His novels have the ring of authenticity because he spent decades in the Royal Navy, rising to the rank of captain. You can find individual volumes and his collected works online.
In the span of a decade, he wrote many “classics of naval fiction”, many of which reside on my shelves in various editions and bindings. However, nowadays he is unfortunately remembered more for his children’s stories, starting with Children of the New Forest. So infatuated was he with America that he travelled the country in 1836 and 1837; the result was his two-series, six-volume (again the three-volume model) Diary in America (this 1960 edited version contains much valuable information on the person and this diary).
Other noteworthy facts: When Napoleon died on St Helena’s on May 5, 1821, Marryat was there and produced a sketch of Napoleon 14 hours after he died. His A code of signals for the use of vessels employed in the merchant service; including a cypher for secret correspondence (4th ed., 1826; later editions entitled The universal code of signals for the mercantile marine of all nations, by the late Captain Marryat, R.N., with a selection of sentences adapted for convoys) was employed by the Royal Navy for fifty years.
His daughter, Florence Marryat, a prolific author in her own right, had published in 1872 the two-volume Life and letters of Captain Marryat. Most of his papers were destroyed after his death so this work provides some primary source material on his life.
As we leave Captain Marryat, I would be remiss in not mentioning three other Royal Navy officers, contemporaries of Marryat, who also wrote naval fiction: Frederick Chamier (bio here, writings here, notice the 3-part novel again); William Nugent Glascock (bio here, writings here); and Basil Hall (bio here, writings here).