Here's what rhymes with boomsail.
fail sale sail veil hail shale vale hale faille male scale mail pale tail tale avail jail nail rail frail gale whale bail stale wail assail bale dale inhale pail snail flail kale unveil wale trail prevail entail email travail quail quale braille mainsail topsail grail impale wassail hightail detail curtail exhale bewail derail gunwale pigtail ponytail foresail monorail taffrail bobtail pellmell lugsail carrell countervail hangnail fingernail martingale nonpareil swallowtail tattletale