NOTES:
Of the 570 G-421s built, 37 Mk Is, 17 Mk IIs and 6 Mk IIIs have been destroyed. 11 Mk Is adn2 Mk IIs have been captured. 3 Mk Is, 4 Mk IIs and 2 Mk III are reported missing. 16 Mk Is, 9 Mk IIs and 4 Mk IIIs have been scrapped. 227 Mk IIs, 200 Mk IIIs and 32 Mk IVs have been sold to the private sector.
| Construction Data: | ||||
| Model Number — | Mk I | Mk II | Mk III | Mk IV |
| Ship Class — | VII | VII | VII | VII |
| Date Entering Service — | 2239 | 2249 | 2256 | 2264 |
| Number Constructed — | 378 | 137 | 55 | Refit |
| Hull Data: | ||||
| Superstructure Points — | 14 | 14 | 14 | 14 |
| Damage Chart — | C | C | C | C |
| Size: | ||||
| Length — | 145 m | 145 m | 145 m | 145 m |
| Width — | 74 m | 74 m | 74 m | 74 m |
| Height — | 63.1 m | 63.1 m | 63.1 m | 63.1 m |
| Weight — | 98,330 mt | 98,800 mt | 98,055 mt | 98,505 mt |
| Cargo: | ||||
| Cargo Units — | 5,000 SCU | 5,000 SCU | 5,000 SCU | 5,000 SCU |
| Cargo Capacity — | 250,000 mt | 250,000 mt | 250,000 mt | 250,000 mt |
| Landing Capacity — | None | None | None | None |
| Equipment Date: | ||||
| Control Computer Type — | M-2 | M-2 | M-2 | M-2 |
| Transporters: | ||||
| Standard 6-person — | 2 | 2 | 2 | 2 |
| Emergency 22-person — | 1 | 1 | 1 | 1 |
| Cargo — | 2 | 2 | 2 | 2 |
| Other Data: | ||||
| Crew — | 38 | 42 | 46 | 46 |
| Passengers — | 5 | 5 | 5 | 5 |
| Shuttlecraft — | 4 | 4 | 4 | 4 |
| Engines And Power Data: | ||||
| Total Power Units Available — | 46 | 46 | 48 | 50 |
| Movement Point Ratio: | ||||
| unloaded — | 4/1 | 4/1 | 4/1 | 4/1 |
| loaded — | 8/1 | 8/1 | 8/1 | 8/1 |
| Warp Engine Type — | FWB-1 | FWB-1 | FWB-1 | FWB-1 |
| Number — | 4 | 4 | 4 | 4 |
| Power Units Available: | 11 ea. | 11 ea. | 11 ea. | 11 ea. |
| Stress Chart – | O/Q | O/Q | O/Q | O/Q |
| Max Safe Cruising Speed – | ||||
| unloaded – | Warp 7 | Warp 7 | Warp 7 | Warp 7 |
| loaded- | Warp 5 | Warp 5 | Warp 5 | Warp 5 |
| Emergency Speed – | ||||
| unloaded – | Warp 8 | Warp 8 | Warp 8 | Warp 8 |
| loaded – | Warp 6 | Warp 6 | Warp 6 | Warp 6 |
| Impulse Engine Type – | FIB-1 | FIB-1 | FIB-2 | FIB-3 |
| Power Units Available – | 2 | 2 | 4 | 6 |
| Weapons And Firing Data: | ||||
| Beam Weapon Type – | FL-2 | FL-5 | FH-4 | FH-9 |
| Number – | 2 | 2 | 2 | 2 |
| Firing Arcs – | 2 f | 2 f | 2 f | 2 f |
| Firing Chart – | F | H | Q | X |
| Maximum Power – | 2 | 2 | 3 | 6 |
| Damage Modifiers: | ||||
| +3 | (-) | (-) | (-) | (-) |
| +2 | (-) | (1-4) | (1-8) | (1-12) |
| +1 | (-) | (5-7) | (9-14) | (13-22) |
| Shield Data: | ||||
| Deflector Shield Type – | FSA | FSC | FSH | FSH |
| Shield Point Ratio – | 1/1 | 1/1 | 1/2 | 1/2 |
| Maximum Shield Power – | 6 | 8 | 13 | 13 |
| Combat Efficiency: | ||||
| D – | ||||
| unloaded – | 45.0 | 48.0 | 73.0 | 74.0 |
| loaded – | 37.0 | 40.0 | 56.0 | 56.1 |
| WDF – | 1.0 | 2.0 | 5.2 | 11.6 |