[Note 1] Originally, 20 ships, including Acheron, were ordered but three more were completed by Yarrow & Company.

Fourteen of the class were completed to an Admiralty standard design, although those built by John Brown and Company at Clydebank (Hind, Hornet and Hydra) had Brown-Curtis type turbines and only two shafts.

[2] Acheron and Ariel were longer (253 ft (77 m)), had higher power (15,500 shp) and were faster, achieving 29.4 kn (54.4 km/h; 33.8 mph) in trials.

[2] Sir Alfred Yarrow maintained that it was possible to build strong, seaworthy destroyers with a speed of 32 kn (59 km/h; 37 mph), and eventually a contract for three such boats was placed with the firm.

Like the John Brown-built boats Hind, Hydra and Hornet, they had only 2 shafts, with steam developed in 2 Yarrow-type water-tube boilers and delivered to 2 Parsons turbines.