The headword appears to be nominative or accusative plural of an unattested noun qalamakeu/s, unless this form (also unattested elsewhere) is simply a mistake for qala/makes, nominative plural of qa/lamac (see n. 1 below); cf. theta 8, theta 454, theta 455, and generally Morrison & Coates (1986): 132-151; Casson (1995): 82-4.
[1] Dative singular of qa/lamac (web address 1); the form, a variant on the more common qalamio/s or qalami/ths (web address 2), appears at Aristophanes, Frogs 1074 (web address 3), and much of this entry comes from the scholia on that line; cf. Hesychius theta19, Etymologicum Magnum 441.24.
[2] It does say the other three ranks, even though there are only three ranks in total (as described below).
[3] If this is not a misunderstanding, or a description of the manning of some ship other than a trireme, then it perhaps refers to the fact that of any vertical rank of three rowers on a trireme, the uppermost man will be situated astern of the middle man, and the middleman astern of the bottom man.