Heave meaning ‘rise up, as on the swell of a wave’ occurs in several nautical expressions; here the allusion is to the way that objects appear to rise up over the horizon at sea. The past form of heave in this sense is hove , but because most English-speakers are completely unfamiliar with the verb in its literal usage, hove is often used as a present form (and a new past form, hoved , is created from it).