This thread is about the Ideal Pirate ship. While all kinds of pirate ship can work, here are my full thoughts of the Ideal Pirate ship and responses to previous posts. I will list them in order of least powerful to most powerful and it will be long.
For the comparisons of modern pirates to piracy in the Honorverse, you can't really compare them. Interplanetary distances are very large, while the distance a Somali pirate needs to travel to reach a freighter is really small. You have to take EVERYTHING with you in space. In a boat on Earth, light, heat and oxygen are all provided for free. With a portable desalination kit you have water as well from the ocean you are travelling on. Not so much in space.
For making a ship faster than it's civilian counterparts, see the following Pearls.
Acceleration by ship mass. The accel table is pre-compensator improvements and should represent the tech available to pirates. Most freighters are in the multi-megaton range, so they will be quite slow. Even with mil-spec impellers a large warship is much slower than a smaller ship.
Effective speed by hyper band. Military hypergenerators, more powerful Warshawski sails and internal compensators let you get to the higher hyperspace bands. Merchants stay in the delta bands or lower and warships range as high as the theta bands, with daring skippers bouncing off the iota wall.
Merchies offering fast service almost always use mil-spec hyperspace equipment rather than impellers for the greater cost savings vs speed as the difference of a few hundred gravities over the first few hours of flight in a week or more trip isn't as great as getting to the higher bands of hyperspace. Or having better particle shielding to have a higher top velocity once you accelerate there. The reason a pirate would want a higher accel, is to frustrate a patrol ships ability to bring you to arms before you get away into hyper. The faster your accel, the smaller the intercept basket for the patrol ship. Conversely, the faster your accel, the larger your intercept basket for catching prey.
Civilian ship with armed pinnace/LAC on boardThe civilian ship can have a solid reputation, while the pinnace does the dirty work. The disadvantages are that the pinnace is short ranged and has to get to energy range to make effective the threat for a merchie to stop for boarding. While pinnaces have been mentioned as able to mount a boarding operation while a ship is underway, I would expect it is a tricky, dangerous operation only done by the most experienced assault troops. Rolling the ship to destroy the pinnace with the wedge, seems a viable counter tactic to me. If the pinnace wanders too far from the mothership, it risks being left behind.
While the loss of the expendable shock troops would be negligible, having the mothership identified would mean your reputation is now not so solid. If the pinnace is onboard the mothership for a customs inspection, you have to have a rational for having a military small craft on an unarmed civilian ship and would most likely need some kind of papers to make it 'legal'.
Using a LAC or LACs would mean a longer range to intercept a merchie, but would have the same problem of having the mothership id'd if caught. The LAC can outrun the patrol ship in normal space, but can not go to hyper. The merchie can go to hyper, but can't outrun anything. Even worse, there is no rational for having a having a warship on your freighter and I'm sure any system government would be upset at that. Forget trying to hide a ship that masses in the tens of thousands of tons in a hold that needs access to space for the LAC to leave the ship from any customs inspection more thorough than 'your manifest looks nice'.
Civilian ship with modifications for weapons/sensorsThe Pearl
Armed merchant ships within the Silesian Confederacy, covers that governments don't like armed ships in their space that they do not control. Here is the relevant textev on Pirate's Bane and Ambuscade as to why they were armed and allowed free rein in Silesa.
War of Honor, chapter 27 wrote:
"So, technically, Pirate's Bane and Ambuscade are auxiliary units of the Confederate Navy. Technically."
"Technically," Honor repeated, and he smiled. "And practically speaking?" she inquired.
"Practically speaking, the Confed Navy's official warrants are nothing but ways around the prohibition against armed merchantmen which are available to those with sufficiently well-placed government patrons. Everyone knows the auxiliaries will never be called upon in their naval capacity. For that matter, at least some of them are pirates themselves!" He seemed, she noted, to actually find that amusing, in a grim sort of way.
Similarly, Marianne, the armed Jessyk Combine freighter, was owned and operated by one of the large Solarian League interstellar corporations, so would be tolerated due to who owned the ship.
So, a ship with weapons will need a powerful patron to secure the warrants for openly carrying weapons without lots of hassles from the polities it visits. Since they are openly carrying weapons, even when they are allowed free passage, I'm sure they have extra scrutiny because of their armed status.
On the other hand, having the weapons off the books so to speak, would entail problems for customs inspections. You would need to conceal weapons hatches and conceal the weapons on the inside of the ship as well. Since most freighters are open space, with the necessary space going equipment out of the way of easy cargo handling, this may not be as easy to hide from a customs officer as you may think. It could be looked over, but a competent inspector doing a careful inspection could very well blow the operation wide open on the hidden weapons as they are not small and draw lots of power.
In either case, you are still a merchant ship which means slow. Your intercept basket will be small, meaning lots of prizes can slip past you and if you are spotted, running can be a problem. If you are using an existing design that is armed, you will be known to be armed by your EW signature and if you are openly carrying arms, your EW signature will be passed around and kept by various polities. If you are concealing your weapons, once you are outed, then pretending to be an innocent merchie is much harder. The advantage is that modifying a merchant ship is relatively cheap and easy as the Masadans did to the insystem ore freighter in Ashes of Victory.
Armed auxiliary shipCpt Bachfisch was able to pick up two auxiliary ships and rearm both of them for his private Q-ship squadron. Almost all will have military particle shielding and hyperdrives to keep up with the fleet, so those are bonuses. Having military impellers would be even better as it would open up your intercept basket, but not all support ships will need them, so it will be harder find one with mil-spec impellers.
You will still be a larger ship, so either way will have a lower accel than a smaller ship. Naval auxiliary ships will have known EW signatures, so trying to hide weapons completely will be harder if the ship you are using is known to normally carry weapons. Once again, warrants from some polity will help if you are openly armed.
building your own mil-spec ship ala PNS SiriusThe two following Pearls,
Q-ships and
Q-ships as convoy escorts/raiders have info for the above sections, but have info on purpose built Q-ships. One of which is;
Pearls of Weber, Q-ships as convoy escorts/raiders wrote:
...building a "military hull" Q-ship is going to be about as expensive as building a light or heavy cruiser of comparable tonnage {in all probability, David meant 'comparable combat capability' - Ed}. Quite probably more expensive.
Once you are getting to purpose built Q-ships, you are into the money range of warships. Not to mention, unless it is a new or unknown design, everyone will know you are a disguised warship by your EW signature. So playing innocent merchant is pretty threadbare. To be a pretend merchie you have to be big which lowers your accel as well.
Warship vs Civilian shipI rate warships above even the best armed auxiliary ship as I like to keep to the KISS principle. A pirate ship is supposed to sneak in and capture ships for disposal of the cargo and ship. Adding in the additional headache of hiding the fact I'm a pirate from government officials into operations seems to be a needless complication to the pirate mission. Yes, warships cost more than civilian ships, but there are corrupt governments aplenty to get your warship from and depending on what you do with your 'civilian' ship, might even be the same or less price!
FrigateFrigates are fast, so you have the ability to run away or run down prey over a larger intercept basket. But frigates have less weapons and endurance than destroyers and were even not used for show the flag operations except by the poorest of navies. Less crew space means less ability for prize crews. Likely to lose vs any patrol ship, including a LAC, it is forced to fight while running. See these Pearls for more info.
Frigates vs. LACs...again! and
Return of the frigate as a combat-effective unit. Yes, I know they both focus on navies and frigates, but the above info on frigates being small, low endurance platforms. While the FF will work well as a pirate, it is not my ideal pirate ship.
DestroyerFast, have a longer endurance than a frigate, and a larger crew for prizes. Able to fight off LACs and FF that stumble across it. While the DD will work well as a pirate, it is not my ideal pirate ship.
Light CruiserHas a crew big enough for prizes and endurance for long patrols. Enough weapons to fight off LACs and give DD's pause. Fast enough to run from most anything else. While more expensive than a FF/DD, the endurance and crew size more than offset that. A cheaper fleet unit and most navies seem to be able to build ships the size of CL as the Grayson flagship in The Honor of the Queen was a CL.
So there should be plenty of them in the galaxy to be had on the black market. Yes, almost all of them will be ancient compared to the current RMN, but they don't need to be new to capture merchies. A pirate doesn't want to fight anyone anyways, so running is better than fighting. A CL still is better in a fight than a FF/DD, so I would prefer a CL as a pirate in case you end up in a running fight from a patrol ship.
Heavy Crusier/BattlecruiserLarge crews for prizes, great endurance, ability to fight off most escorts and patrol ships make these great pirate ships. Battlecruisers are considered capital ships, so will draw way more scrutiny than other pirate ships once they are discovered. (Ala, sink the Bismark) They are also slower than DD/CL and cost more to operate, so not my ideal for a pirate ship.