The spelling of the word "Jears" might seem a bit perplexing, but it can be explained using phonetic transcription. The letters "j" and "e" in this case represent a voiced palato-alveolar affricate sound /dʒ/. The following letters, "e" and "a," denote a diphthong sound /ɪə/ which is made up of a short "i" sound followed by a long "a" sound. Finally, the letter "r" represents a vocalic "r" sound /əɹ/. Therefore, the phonetic transcription of "Jears" is /dʒɪəɹz/.
In nav., an assemblage of tackles by which the lower yards of a ship are hoisted or lowered.
Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874.