Hi, Benedicte here.
As I recall it, my main Endy did 14.78 knts. As the poster above suggested correctly, this ship had Copper plating/navy hull/naval clock. The ship I capped from you or your clanmate was indeed slower, roughly 13 knts. I emptied it out completely but did not slap mods on it.
You were, in fact, catching me. Which is evidenced by the fact that 2 of your other clanmates (Endy and Trinc) managed to tag me. After sending the fleetship to escape; I turned and sank the Endy after which the Trinco escaped with 10% health left.
After this battle, it seems you appeared outside with 4-5 more players. You were in fact gaining on me again, but as you can see from your own screenshot, Meataxe was hunting with me. He came back in a rattlesnake and covered me, rendering you unable to tag me as he would be in the way. After a few minutes you gave up the chase.
Long story short: you WERE faster, just did not play out the chase well enough.
Apologies for any frustration caused, but I dont think anything is wrong or tribunal-worthy here.
Cheers. B.