
Here I am writing a long detailed response and peter tries to steal my thunder before I can post

. Anyway, I doubt the fish in general will provide 2 gpt since most of them are in corrupt towns. They will provide extra fpt, but I wasn't even going to try to calculate the value of that. Instead, here is my (much more long-winded) analysis:
I’m not sure what the other option is, but actually, after looking at some numbers, it may really be better economically to build frigates and treat them as mobile shields than not to build them.
Consider the following hypothetical situation: we have a town that completes something on turn 179 (our next turn) and is at 12 spt. I’m going to ignore the fact that the spt will change at the end of our Golden Age because it complicates things, but I don’t think it changes the conclusion. Also assume we will complete Flight on turn 194. If we look at 2 options:
1. Build wealth for 7 turns, then switch to a bomber prebuild on turn 186 to compete a bomber on 195. We get an extra 3 gpt (based on 12 spt) for 7 turns making us a gain of 21 gold.
2. Build a frigate for 5 turns (a frigate is 60 shields, right?), build wealth for 2 turns, then switch to a bomber prebuild. We get 3 gpt for 2 turns = + 6 gold. The frigate costs us 2 gpt for turns 184-195 which yields -22 gold. We are left with a loss of 16 gold.
However, on turn 195 we can disband the frigate in a town that is at 1 spt where we would like to rush a bomber. We gain 15 shields in that town saving ourselves 60 gold in rushing costs.
I know nobody has recommended building wealth in towns where frigates have started, but what are the other options? In my hypothetical, we want to start the bomber prebuild on 186 so we have 84 shields to work with until prebuild time. Assuming the town already has a library, a marketplace, and maybe a courthouse and a university, what else could we want?
If we really hate frigates, then I guess it is even more economical to build wealth first for 2 turns then the frigate, or, even better, a cavalry to live for a shorter period then disband for 20 shields, but I also would like to get those galleys off our fish and maybe take a pot shot or two at the Nuts coastline.