Or search: cox, gob, tar, jack, seaman, mariner, steerer, coxswain
2 Syllables: SU
clearance, Ephraim, fearsome, ference, Pearson, serum, theorem
3 Syllables: USU
adherence, adherent, appearance, coherence, coherent, imperium, Macpherson, reappearance
4 Syllables: UUSU
disappearance, incoherence, incoherent, interference, perseverance

Found 20 words across 3 groupings. Skipped 2 excess words of a similar stem.