does it make any sense to place large ships at all?
Large ships are better than small ones if no Blooming Trader Guild. The key question is not only the production level, but also the cost to produce it.
Let’s take as example luxuries ships for 3h production without Blooming Trader Guild (data taken from minmaxgame)
A large ship produces 62 luxuries, equivalent to 124 delicacies-eq (ratio 1:2) while a small ship produces 57 luxuries = 114 delicacies-eq. Per square, the production in delicacies-eq is 5.90 and 7.60. Until now, small ships are more efficient per square. But let’s take a look at their production costs.
The equivalent costs (in delicacies-eq) for the large and small ships for 3h are 62 and 76 respectively. Per square, the costs are 2.95 and 5.07 respectively. Then, the ratio production/cost for large ships is exactly 2.0 and for small ships is exactly 1.5. In result, per square, you gain 5.90-2.95=2.95 delicacies-eq with the large ship and 7.60-5.07=2.53 delicacies-eq with the small ship. In an hourly basis, you gain 0,98 delicacies-eq with the large vs 0,84 with the small.
ONLY if we move to a 15min production time, small ships are better than large ones. It is also true that large ships with production time of 6h and 9h are worse than any production time with small ships, but they produce overnight.
Finally, all this depends on your Trader Guild level as production is increased while cost remain the same. For 3h production, large and small ships are equivalent if your Trader Guild is at level 17 (production +25%). More levels in the Blooming Trader Guild will make small ships more appealing (much more with shorter production times).
Am I wrong? Can anyone confirm my numbers?