So I may have missed it in the books, and didn't seem to find it here on the forums, but my group and I have acquired a Gozanti class cruiser, but we aren't satisfied with speed 2. So we would like to look into making an engine swap, or adding an engine to up the speed to speed 3, in line with some other Sil 5 ships. We were looking at some of the engine components in the engineer book, and adjusting rules and costs for adding or swapping engines. Have any of you attempted anything like this, if so, how did you go about it?

You can do this by RAW using the starship/vehicle crafting rules in fully operational however those rules are pretty bad in general... not balanced (not enough hp, too much strain, too much armor, etc.) and not sufficiently general to reproduce reasonable approximations of official ships. Check out the nubian design Collective's whole vehicle crafting handbook for a set of house rules designed to address that.

16 hours ago, Kiowa706 said:

So I may have missed it in the books, and didn't seem to find it here on the forums, but my group and I have acquired a Gozanti class cruiser, but we aren't satisfied with speed 2. So we would like to look into making an engine swap, or adding an engine to up the speed to speed 3, in line with some other Sil 5 ships. We were looking at some of the engine components in the engineer book, and adjusting rules and costs for adding or swapping engines. Have any of you attempted anything like this, if so, how did you go about it?

The high output ion turbine attachment is the easiest way to bump up your speed a notch.

1 hour ago, penpenpen said:

The high output ion turbine attachment is the easiest way to bump up your speed a notch.

I was going to say.

Swapping engines would be a difficult task as they are likely to be massive things and will require all kinds of equipment.

@Kiowa706

I would say that the PCs would need to have or rent a proper place to perform such a refit (dry dock, space dock, garage, what have you), this would probably cost money to rent or buy.

Removing the old engine should take at least a week. As it wouldn't be "plug and play", you should use the Engine Crafting Rules (like EliasWindrider said, the Nubian Design Collective is a better rules set than that in Fully Operational, but you can use either).

Crafting the new engine has a difficulty, cost and time associated with it in both rules sets, but I'd increase them all (Setbacks and maybe an Upgrade for the Difficulty) to represent the extra work involved with such a refit.

Cheers!

Thanks for the info. I knew about the attachment, but the group seemed as if they didn't want to waste the hardpoint on that when other attachments help us out more. Which is why we were looking at a full engine swap. I'll take a look at the Nubian Design Collective and see what I can find.

2 hours ago, Kiowa706 said:

Thanks for the info. I knew about the attachment, but the group seemed as if they didn't want to waste the hardpoint on that when other attachments help us out more. Which is why we were looking at a full engine swap. I'll take a look at the Nubian Design Collective and see what I can find.

Well, that might be a valid concern on paper, but really, advise your players not to worry about it unless all the hard points are used already. The Gozanti has 4 which is quite plentiful, and plenty of guns that can be replaced to make more powerful. It's easy to get too stuck in planning for the stuff you want without considering how and when to get it.

A high-output ion turbine costs 5,500 credits and is good to go. If you don't want it anymore, or need your hardpoint for something else, you can yank it out and put it in the cargo hold, or sell it to recoup some of the cost. It's a bit vague how complicated it is to install or uninstall attachments, but on a Gozanti, I'd consider it a pretty harsh GM ruling to let a party of 4-5 PCs having to put in a week's worth of spare time to do it. More like an afternoon's work for 1-3 people.

Replacing the engines without losing a hardpoint means that you only have the single ion coil as an option. Shoving one of those in with just the basic stats means you will end up with the following stats (difference from stock in parenthesis): Speed 1 (-1), Defense 0/0/0/0 (-2/-2/-2/-1), and System Strain Threshold 25 (-11).
On the other hand, it only costs 500 credits to design one and it's an Easy mechanics check, so a decent mechanic should be able to score a lot of advantages when cranking on out. To get it somewhat on par with a stock Gozanti, you need 2 advantages/1 triumph per point of raised Speed, 3A/1T to increase defense by +1/+1/+1/+1 and 2A/1T to raise System Strain Threshold by 1. Of course, you can also install mods to the engine once it's done, 3 that increase speed by 1 and 3 that increase SST by silhouette (5). These get very hard to install quickly and failing means you cant try again, not to mention it costs 1,000 per attempt. Since speed is capped at 3 using these rules, the most efficient option would probably be to go for enough advantage/triumph to upgrade speed twice and shields twice (10A, 7A+1T, 4A+2T or 4T) and then going for installing 2 strain threshold mods. If the number of advantages fall short, it might be worth skimping on a speed upgrade, and hope you can make one out three possible rolls to install a +1 Speed Mod at Difficulty 5 (but don't fail with a despair, unless you want to bork up the engine. Meaning that with a good mechanic, you could get an engine that gives a Gozanti +1 Speed, +0/+0/+0/+1 Defense and -1 System strain for as little as 2,500 credits. Yay!

Nope.

You've designed the engine. That was the simple part. Now you need to rebuild a corvette-sized starship.

The assembly stage of of a Sil 5 ship a difficulty 4 mechanics check and "A team of 100 or more, 100,000 credits for additional supplies". Whether this includes the cost of a space dock and heavy duty tools is up to you.

It's also going to take 50 days (1200 hours reduced by 2 hours per success). If the PCs don't have lots of friends willing to work for free, you need to consider labor cost as well. Special Modifications sets the rate for "Basic maintenance and repair work" at 1000-2000 credits per month, and "Contracted Work" at 5,000-10,000 per month, but let's say we're very generous here.

100 low-wage maintenance techs, working 13,3 hours per day, 7 days a week, will do that in 90 days, or 3 months. Bargain bin wages means 300,000 credits.

If you're a kind GM you could consider the Gozanti a pretty small Sil 5 ship and knock the time and manpower down to half (or not, it's equally valid to have big Sil 5 ships double the requirement) or halve it because it's "just" an engine replacement, not a new vehicle built from scratch (again, if you're feeling very generous). That means 50 guys working 600 hours each, so 45 days or 1,5 month. That's still 75,000 credits.

Sure, a few advantages on that mechanics roll for assembly can knock these costs down significantly by throwing a bunch of advantages at it (to 1 hour of work and 50% of the cost of supplies for a mere 16 advantages), but even then that 5,500 credit high-output ion turbine should be looking like a pretty viable choice, particularly since Fully Operational has a few new rules that lets you add an hardpoint to your ship for 500 credits or just rolling a Triumph...

TL;DR; Rebuilding a Sil 5 ship gets very complicated and very expensive really fast.

Yea looking at the Nubian Design Collective, losing that defense isn't worth it in my opinion. I'm a player btw. The loss of a hardpoint is worth keeping the defense. I'm going to suggest going the High Output Ion Turbine option.

On a side note, who ever worked on the Nubian Design rules did a great job. They're way better than the engineer book. I'm impressed.

3 hours ago, Kiowa706 said:

Yea looking at the Nubian Design Collective, losing that defense isn't worth it in my opinion. I'm a player btw. The loss of a hardpoint is worth keeping the defense. I'm going to suggest going the High Output Ion Turbine option.

On a side note, who ever worked on the Nubian Design rules did a great job. They're way better than the engineer book. I'm impressed.

Thank you, my design goal was the minimum departure from RAW needed to get a 95% quality match at reproducing 95% of official ships, with enough generality to be able to make a ship that was good at anything with enough constraints that you can't make a ship that is awesome at everything, targeting a power level on par with official ships. In terms of where balance is at, about the best ship a tricked out for crafting player could make with some pretty good rolls is the kst-100 but with a speed of 5 and better sensors, and a different weapons load out. The aka'jor (mando super) shuttle from friends like these is technically possible to craft but the rolls are difficult enough that you wouldn't expect to be able to do it without some serious crafting grind.

It's been an iterative design process, finding and fixing problems. While I did most of it I had a lot of help from the community in terms of identifying problems and even some suggestions (e.g. weapon banks) that made their way into the book. Any help any help you could provide trying to replicate ships and pointing out what doesn't work would be greatly appreciated. Btw there are engine mods and crafting upgrades, and hull crafting upgrades that can get you the defense to match, but if you're only w swapping an engine then you'd only have what you can get from the engine but 1/1/1/1 is easy enough to get from an engine.