Just finished statting up the Churchill class using the handy Construction Tables and Excel spreadsheets from https://fasaststcs.com/ which did an excellent job of making sure I had the right combination of computer core, weapons, and shields.
The date the ship entered service is either determined by canon or fanon materials when I can find them. For refits, I roll 2d6 + 3 to generate a number of years between 5 and 15 (average of 10), as well as the last year the ship was in service from the last refit. If a refit does not change any stats for a ship when it is converted to SFC, the previous refit was actually the last refit for that class of ship. If a ship has been in service for over 45 years, it will be retired, unless canon information specifically has a retirement date for that class.
The number constructed is determined by dividing 20 billion by the cost of the ship, then multiplying that value by (2d6 + 3) / 10 to get a number that ranges between 50% and 150% of the base value.
To determine availability for each component, instead of using the availability values listed in the tables, I gave a 3% chance per year the part is available at the time the ship first entered service, or received a refit, to a maximum of 75%. If the part was made available the same exact year, then there is a 1% chance it is available.
These rolls are made for each component. If there is a mix of technology, then the least technologically advanced part that succeeds is the one that accounts for all components. For example, if there are 4 phaser banks, then rolls are made until 4 successes are recorded. In this example, 1 FH-12, 2 FH-10, and 1 FH-9. Since the FH-9 is the "least" advanced phaser system with a successful roll, the ship will have 4 FH-9 phaser banks.
This seems to work out pretty well so far, but I'm not sure how to handle whether or not a ship will have multiple computer cores, as this has a huge impact on what combination of weapons can be installed on a ship. It looks like there are a few Battleships that have two cores, but most others that I've seen that use this system only have one.
The issue I had with the Churchill was its class progressed from XII to XIII to XIV between the 3 versions, and I'm not sure if that's okay or not as it represents an increase in the mass of the ship. Interestingly, due to this, it seems that its cruise, max, and emergency warp speeds were impacted by being slower for the third version of the ship, which was kind of cool to see.
Oh yeah, calculating warp speeds. While the construction tables do provide a cruise/emergency speed value, they seem to use the warp scale from TOS. To make things consistent across eras, I've decided to use an estimation of the TNG warp scale, though I'm sure I will need to make adjustments and recalculate as I go.
To calculate a ship's cruise warp speed, I take the power units available and divide it by the movement point ratio. I don't take into account how many total engines there are, as the power units available changes based on the number of engines already.
Next, to calculate the ship's max warp speed I take their cruise speed value, raise it by the power of 10/3 (to get the light speed value), multiply that result by 1.25, then raise the final value by 0.3 (to convert it back to a warp speed).
Finally, for the emergency warp speed, it's the same as the max warp speed, but the light speed value is doubled. I do think eventually this calculation will break (produce a value over warp 10), but I'll figure out a fix when that happens.
And that's how I build a ship from scratch.
