Skip Ray Blastboats

[belshazzar]

I interpreted it like this: You roll to hit it like it were a capital ship (so to hit bonus and hull bonus due to scale difference apply). With its main weapon it works as a capital ship (scale difference apply... big problems to target dodging starfighters!) other weapons are starfighter scale and work like starfighter weapons.

[Roguesrule]

You roll to hit it as if the blastboat was starfighter scale. That's why they are also flown with starfighter piloting and not capital ship piloting. If they are hit they resist damage as if they were capital scale.
As was already said the ion cannons are capital scale and treated light that for hitting and doing damage. The other weapons are starfighter scale and treated like starfighter weapons.