The word submersibles is playable in Words With Friends™, no blanks required. Because it is longer than 7 letters, you would have to play off an existing word or do it in several moves.
Words With Friends™ Letter Score: 23
Highest Scoring Words With Friends™ Plays In The Letters submersibles
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Seven Letter Word Alert: (37 words)
bemires, bemuses, beslime, blesser, blesses, blisses, bribees, bruises, bumbler, bumbles, burbles, erbiums, imburse, issuers, leisure, limbers, lumbers, messier, misrule, misuser, misuses, mueslis, mussels, rebless, reissue, resumes, ribless, rimless, rubbles, rumbles, rumless, sessile, slumber, smilers, sublime, surmise, useless