Well....
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FEDERATION TOS FAST CRUISER
Designation: F-FCA
BPV: 179
Crew: 42
Marines: 10
Shield 1: 30
Shield 2 & 6: 24
Shield 3 & 5: 20
Shield 4: 20
Total Shields: 138
Yr available: -21
Last: 10
Movement Cost: 1
Size class: 3
Turn Mode: D
Acceleration: 15
HET breakdown: 3
Total Warp Power: 60
Impulse Power: 4
Aux Power:
Total Engine Power: 64
Battery: 4
Transporters: 3
Tractors: 2
Shuttles: 4
2x Photon
2x Missle Rack G
6x Phaser 1
2x Phaser 3
What do you get when you put two more warp engines on a standard heavy cruiser?
This, pretty much.
If you notice, Fast cruisers (like the FD7) have thier heavy weapons decreased to allow them more speed and power reinforcement. Plus, it means they can do overloads while running circles around the enemy.
Just because it has extra nacelles doesn't make it a battlecruiser, or add any special extra super shielding. If I bash a frigate with 4x Excelsior nacelles, does that make it a battleship now, with 50 sheilds, just because it has bigger engines?
I say this because I have a distaste for hotrod starships. The only race to ever feild a super heavy cruiser (In SFU history and ingame) were the Romulans, and that idea was killed when X ships came along.