MegaTraveller doesn't give actual sizes for ship turret weapons, though they do give masses. A TL-13+ laser masses 4 tonnes. The biggest vehicle mounted fusion gun masses 0.31 tonnes. The laser requires 250MW of power, which means a ~1 DTon power-plant at TL15 that masses 27 tonnes. The fusion gun requires 61.7MW of power, which requires (assuming a dedicated power-plant with the lower efficiency that implies) 6.86 m^3 and masses 13.72 tonnes.
A ship's laser is a terrifying weapon in planetary combat, but smaller than a tank's fusion gun it is not.
The odd thing is that the vehicle lasers don't demonstrate nearly the same effect and have different ROF to starship ones. The starship lasers do something like three times the damage per MW (and the pulse lasers fire faster, too). They clearly weren't converted from CT using the same method as Striker weapons were.
A ship's laser is a terrifying weapon in planetary combat, but smaller than a tank's fusion gun it is not.
The odd thing is that the vehicle lasers don't demonstrate nearly the same effect and have different ROF to starship ones. The starship lasers do something like three times the damage per MW (and the pulse lasers fire faster, too). They clearly weren't converted from CT using the same method as Striker weapons were.
