Wikipedia dixit:
Speed:
40 knots (46 mph; 74 km/h)[1]
41 knots (47 mph; 76 km/h) on trials.
Given their machinery development of 93,210 kW (125,000 hp), equivalent to that of the 17,000 ton cruisers of the Des Moines class, the target speed was over 40 knots (74 km/h), but the ships were left virtually unarmoured. As a result, the three completed warships achieved 41 knots (76 km/h) during trials (43 knots (80 km/h), according to some sources)
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Quindi si, 41 nodi appare adeguato, con una mostruositą di potenza del genere
Lo scafo appare verde nei modellini che ho visto e nel modello 3d originale, mi fido

le foto in bianco e nero purtroppo non mi aiutano..
Provvedo a tirare il cavo, grazie mille!
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So yes, 41 knts are ok, with a similar, huge power.
Hull appear to be green in scale model i found and in original 3d, b\w photos can't help.
I'll apply suggested correction to flag cable =)
Thanks a lot!