### Clue: One not being straight with set of engineers in ancient craft (6)
### Answer: BIREME 
 ### Explanation: Definition: ancient craft
 BI(short for "bisexual"/one not being straight/heterosexual) **plus**(with) REME(abbrev. for the "Royal Electrical and Mechanical Engineers", set of engineers in the British military).
Defn: … with two banks of oars.