Rocinate has a volume of about 750 dTons +/- 50. In Traveller terms she'd be an 800 dTon ship due to the 8 hardpoints. In the Expanse universe a frigate is simply a warship without a railgun, vs a destroyer (spinal mount railgun), cruiser (single turreted railgun) or battleship (2 turreted railguns). PDC's are abolutely an offensive weapon - see the
spin station battle or
Rocinate vs Pella.
The entire idea of "point defence" is 2300 is silly. The missile weapons used do not impact the target, but fire blasts of X and gamma radiation from a significant distance away, although less than you'd think. Bomb-pumped nuclear "lasers" are not focused but instead are collimated. They are reasonably narrow at 100 km or so, but quite broad at 1,000 km. Any anti-missile defense has to hit the missile whilst still warping towards the target. Remember, warp 1 is 1,200 km/s. An attacking missile is only within 1,000 km for a fraction of a second before detonating. Compare with a modern sea-skimming missile which can be engaged effectively for at least 10 seconds by CIWS.
The Mongoose 2k3 laser is a different beast to the GDW one. The latter is a 6 m focal array firing hard X-Rays with a focal range of 2 light-seconds (1.2 million km). The Mongoose laser weapons use multiple small focal arrays and UV, and range is determined by the diameter of an individual FA element and the frequency. Given 2 m FA elements with UV, the focal range of a Mongoose laser is about 100 km. Normal guns are outranged by bomb-pumped nukes, and thus even with "area-defence" lasers, there is no defence against missiles.
Point-defence lasers are defined to have a range of adjacent (< 50 km in the AEH, < 100 km in the boxed set), and so are useless in all circumstances, especially as bomb-pumped nukes are defined as having a range of "close" (i.e. 150,000 km, which is unrealistic).
As a note, travel times are inconsistent in Mongoose, and apparently combat speeds are slower.
Anyway, the Mongoose turret lasers defy physics, since their stated range is far beyond what is possible with the frequencies involved. However, within the rules, they can at least attempt to engage incoming missiles, since they have the range range as det-warheads. However, the time needed to develop a firing solution means that counter-missile laser fire is going to be ineffective.
In the Mongoose rules, submunitions will be decisive. Cheap, a lot of damage, no range disadvantage, and no chance of point-defence.
