A 400 metre ship is not a canal boat
Someone spotted ships all evening and said they never noticed rarity or size affecting the points. We went and looked, and they were right, in a way that was worse than the complaint.
Here is what the collection held that morning: 699 ship cards, 416 of them with no rarity stored at all, 280 uncommon, three rare, and not one epic ever minted by anybody. A 400 metre CMA CGM TROCADERO and an eight metre Amsterdam canal boat wore the same ribbon and paid the same 35 XP.
Why the old formula could not tell them apart
Rarity was category points plus size points. Cargo and tankers scored zero for category, and size could only add three, so a freighter of any length was capped at uncommon: 400 metres and 82 metres were two steps apart at most. Meanwhile a passenger hull got two points for being a passenger hull, which is how a water taxi ended up in the same tier as a container ship. That is the whole complaint in one sentence.
Epic was worse. Six points needed a 90 metre sailing vessel, and sailing and pleasure craft are private classes: the game refuses to mint a card for them at all, because a recreational boat's name and movements belong to a person, not a company. So the only road to epic outside the hand-curated legend list ran through hulls you are not allowed to catch. It was not rare. It was shut.
What it is now
The tier is the size, measured against the class the hull belongs to, because "big" is a different number of metres to a tug than to a bulk carrier. Four ladders: cargo and tankers step up at 150, 250 and 350 metres; passenger ships at 100, 200 and 300; tugs, fishing boats and fast ferries at 35, 70 and 150; everything else at 50, 150 and 250.
Those numbers are not a designer's taste. We took every hull our receivers have seen with a known length — 21,820 of them — and put them in buckets, so a tier now means roughly "this share of its class is bigger than that". Common is the ordinary half, uncommon the next third, rare about one in twenty, epic one to three in a hundred. When the network grows and the mix changes, the same histogram is the thing to re-run before anyone touches a threshold.
The practical effect on that evening's catches: the four 400 metre container ships become epic, a 304 metre ZIM VIETNAM and the 253 metre CRUISE ROMA become rare, the 316 metre MEIN SCHIFF 2 becomes epic, and the canal boats go back to common where they belong.
Points you can see
The tier was also worth too little to notice. It paid 10 to 25 XP out of a payout that was usually 35 to 135, and everything above it came from one-time discovery bonuses: first ship under that flag, first of that type, first of that size class, first from that shipyard. Your first evening is nothing but those bonuses, so rarity was invisible exactly when you were forming an opinion about it. They also run out, while the tier keeps paying forever.
So the ends of the ladder are now 25 times apart instead of 10: common still pays 10, epic pays 250. The average catch moves from about 17 to about 25 XP. The curve has not been rebalanced, only stretched.
And the "+N XP" pop now tells you what it is made of. Catch a rare hull at night under a flag you have not seen, and it says so: the tier first, because that is the answer to "why is this one worth more than the last one", then the discoveries, then the night bonus. The parts add up to the number above them. Achievements stay out of the list. They have their own banner, and a list that does not add up is worth less than no list.
The cards you already have
Every card that never got a tier written will get one, and cards the new ladder scores higher will be raised, including the first two dozen epics this collection has ever held. Nothing that was shown to you at a tier gets quietly demoted; the canal boats keep their uncommon ribbon unless we deliberately ask for a clean slate. And no XP is recalculated. A payout was correct for the rules of the day it was paid, and we do not go back and argue with it.