There is a formula base:
FINAL RENOWN = {base ship renown value} * { (0.75 * realism %) + 0.25 }
Say you sink a 250 Renown ship and are playing at 50% realism, your calculation is as follows:
FINAL RENOWN = {250} * { (0.75 * 0.50) + 0.25 }
FINAL RENOWN = {250} * { (0.375) + 0.25 }
FINAL RENOWN = {250} * { 0.625 }
FINAL RENOWN = 156.25 renown
So if you play at 0% realism, you will still get 25% of the renown or 62.5 renowm.
Welcome aboard!!!