(1) The rockets in question are spin stabilized in flight with machined nozzles. Yes, they are black powder and yes they will not be precision weapons. They will, however, be one hell of a lot more accurate than 19th century black powder rockets without spin stabilization.
...Seriously?
The most banal Hale rocket. It's spin-stabilized, it's XIX century, and it's far too inaccurate.
(2) The rockets in question were fired en masse at a volume of watter which had been preranged and pretargeted. They were not aimed "at" the ships at all, and the vast, bast majority of them missed.
I never doubted that, you know. My criticism was about the possibility of obtaining anything besides cosmetic damage that way.
(3) If anyone was paying attention, the devastation was primarily the result of fires, set in the super structures. There were some deck penetrations, and the deck armor was thin.
If deck armor was THAT thin, that means that there are no deck armor at all. Seriously, how much armor do you need to stop a warhead that could realistically move XIX century rocket?
No one on the other side had the sort of heavy mortars which have been mentioned in this post, so most fire would be coming in on a fairly flat trajectory. (Had such heavy mortars been under construction, Merln would have known about it, and the deck armor --- which was much better on the Gwyllym Manthyr than on the ironclads which were never supposed to engage such heavy foritications and guns --- would have been considerably thicker.)
So they basically made a really stupid mistake?
The rockets became available to the Church only after the ships in question had been launched, and therefore represented a threat the designers had rated as low when they built the ships, Given the need for the thickest belt and casemate armor they could carry, they "skimped" on deck armor . . . just like a lot of RL late 19th-early 20th century naval architects,
...The average XIX century mid-size ironclad usually have 1-1,5 inch armored deck. Considering that Charisian armor was stated to be MUCH better than wrought iron or compound, I literally fail to see, how such armor could not stop the rocket warhead.
(4) The rickets in this casecame in on a steeper trajectory than cannon fire would have at that range, and it was specifically stated in the book that these were extraordinarily large rockets which had been specifically designed to carry heavy warheads designed to attack protected targets, which is one reason their range was so extraordinarily short and their trajectories were so steep. They were very short ranged weapons whose extremely nose-heavy design pulled them down at a very sharp angle.
I.e. the rockets that could NOT be build on XIX century level. At least, not reliably, which means that the whole "rocket volley" thing basically became an exercise in blowing up your launchers, because the probability of rocket's explosion during launch increased exponentially.
Not to mention that I seriously doubt that "extremely nose-heavy design" would do anything except making rocket flight completely unstable.
Sorry, RFC, but this just wouldn't work.