Right. From
What I can gather the Riga’s were very useful ships why cache them? Aren’t they superior to an Essex or Vincent ?
Rigas were already out of service when the Amaris Coup began (any examples in the Exodus would have been either captured vessels originally sold to the Rim Worlds Fleet or reactivated from the SLDF's massive reserve fleet).
And the rules don't really address this, but age is a factor. Ships wear out. Even if they're properly cared for in long terms storage, there's going to be problems. Ultimately, the Rigas were older than most of the rest of the ships in the fleet, that means putting them back into service would take a lot more work than a more modern hull.
In a way, even the Aegis was a younger ship, having been extensively rebuilt before the Reunification War and in continuous service with additional refits afterwards. Even if the stats aren't changed, bringing the Rigas up to full snuff would probably be on that level. It would be a major project given the Clans' relatively limited naval infrastructure. And the clans had alternatives lying around, far more than they could properly utilize. Hence the naval caches.
(there's also something to be said for standardizing to a smaller number of different hulls to reduce your logistical tail)
For the Word of Blake, they needed a lot of ships quickly, so they couldn't really pick and choose, they had to put in the extra work to get the old relics up to snuff. Hence, the Rigas got to come back along with many other classic designs.
For a Clan to bust out an old Riga, they'd need to have a pressing need to justify the expense of restoring it, along with a lack of alternatives that could do the job (if not as well, then at least well enough without requiring as much work). Since the naval caches are almost empty now, this might be a pretty good time for it.
