26 Jul 2018

How long is the DEFIANT-class?

The Defiant-class was designed by James Martin under the direction of Herman Zimmerman and Gary Hutzel. According to Martin, the initial instruction for the designers was that it was a "beefy runabout." The design sketches (from Star Trek - The Magazine) by Jim Martin show the evolution of the Defiant class.



According to Gary Hutzel, during the early development stages of the ship, the Defiant was to be "a new hot battleship that would really set a new standard for an action ship in the series. First, there was lots of talk like 'How big is the Defiant?' Well, we'll make it really small and really powerful, that it would be so powerful and scary, nobody would mess with it."
(DS9 Season 3 DVD special features)

According to Doug Drexler, "The size of the Defiant was a hot potato from day one. Rick Berman wanted a small pocket battleship (a couple times longer than a runabout, with the girth of a regular starship) Gary wanted at least 500' (152,4 m)." 
(drexfiles.wordpress.com 2008/12/20)

In the DS9 Technical Manual we have a length of (560') 170,7m.

Calculation:

  • The premise for all my deck calculations: a deck is 2.5m + 0.5m for EPS cables, power cables, ... = 3m height for a deck. Starfleet ships have 4m (3m deck high + 1m Jefferies tube). 
From the MSD (Master Situation Diagram) we know that the Defiant class has four decks.

LCARS by drex files - Doug Drexler
The following picture shows the Defiant class with the decks from the MSD.

schematic by TheLightWorks

This will calculate a length of 125m. Because of the strong armor of the Defiant class, I would deduct 1m for each deck so that the total height per deck (with Jeffries tube) can be met of 4m.

This results in a length of 121m for the ship.

If the USS Defiant would be 170,7m long (DS9 Technical Manual), then it would have a deck height of 5,38m (-1m Jeffries tube = 4,38m corridor height). With Gary Hutzel's 152,4m, that would still be 4,8m (-1m Jeffries tube = 3,8m corridor height).

On screen, the Defiant class looks small and fits well with 121m to Deep Space Nine.  This is also credible for a crew of ~50 members.

screencapture by trekcore.com (DS9 - Opening Credits)
Inconsistency:
  • some dialogues suggest there is a "deck 5" (in DS9: "Way of the Warrior", "Rejoined", "Starship Down", "To the Death")
  • The main Shuttlebay was a later addition (DS9 "The Sound of Her Voice") so that the Shuttle Type 10 (with 9,6m) is a bit too long to fit into it.
  • two rows of windows on deck 4
  • the Defiant Turbolift LCARS shows 6 decks
LCARS by "Captains Chair"-CD-ROM