Traveller manpower requirements are based on the ships displacement tonnage, and installed tonnage of various equipment, so a conversion from DT to HERO terms is needed.
that I posted a while back and can post again if needed.

These figures are for military ships of 1,000 displacement
tons or more

Sections:
Command, Engineering, Gunnery, Flight, Ships Troops, Deck

Each section will have a an officer in charge and a senior nco

Command: Average of 10

Engineering: 1 per 100 tons of installed drives and powerplant

Gunnery: 1 per turret Battery, 2 per weapons bay, 1 per 100 tons of main weapon battery[Spinal]

Flight: flight crew as needed +1 1 crew chief/mechanic per 3 craft carried. 10 per launch tube if launch tubes are equipped.

Ships Troops[If Carried] Varies considerably by type of ship. but the formula I've always used was on the order of
Escorts: 1 squad
Destroyers: 1 Platoon
Cruisers: 1 Company
Capitol Ships: 1 Battalion

Service and Support: 3 per 1,000 displacement tons, unless carrying troops than 2 per 1,000 tons

as far as figuring the exact engineering and main gun crews, go by 1/50 AP or something similar.

these figures also assume standard automation/computer support. higher degrees of automation will cut the crew size by 10% for enhanced, and 20% for Advanced. this concept comes from Traveller 4th Edition however