The fifth line on a lock plate isn't about the lock

A cast plate, riveted at the edges. Five numbered lines: close the gates behind you. Check both paddles are down. Raise the paddle nearest you first. Wait for the levels to match. Leave it as you found it — the last one cast in red, the rest in plain cream.

Four of those lines are about operating a lock. The fifth one isn't, and it's the reason the other four still work tomorrow.

What is this plate actually instructing?

How to move a boat through a change in water level without letting the water win.

A lock is a box between two different heights of water, sealed by gates at each end. Get the sequence wrong — both gates open together, or a paddle raised on the wrong side too soon — and the water does what water does, fast and without asking permission. The five lines are the sequence that keeps that from happening, cast into a plate so it can't wash off, fade, or be misremembered under pressure.

Why does raising the nearest paddle first actually matter?

Because doing it in the wrong order lets the two bodies of water fight each other through the boat.

Open both paddles at once, or the wrong one first, and water rushes in unevenly — enough to throw a boat against a gate or a wall before anybody in the lock has time to react. Raising the nearest paddle first lets water in gradually on one side, so the level inside climbs evenly rather than surging. It's not a rule of etiquette. It's the one order that doesn't put the boat in the path of a current.

Why is the fifth line the one cast in red?

Because it's the only line on the plate that isn't about the machine in front of you.

Lines one through four describe operating this lock, this time, for this boat. Leave it as you found it is about the boat that comes through after — gates shut, paddles down, nothing left running that the next crew would have to notice and fix before they could start. Casting it in a different colour is the plate admitting that this line does a different kind of work than the rest.

Who actually owns the wording on a plate like this?

The sequence itself is a fact about how locks behave — a specific waterway authority's actual cast plate, with its own crest and wording, is theirs.

Raise the nearest paddle first and wait for the levels to match describe physics, not house style; nobody invented that order, water did. What a real canal authority owns is its particular plate — the typeface, the crest, the exact wording it casts and bolts to its own locks. If a real authority's actual plate is the point, that's theirs to licence. An invented one, on an invented canal, does the same civics without needing anybody's permission for the crest.

Does this work as something to give someone who isn't a boater?

Yes, for anyone who's spent time keeping a shared thing working rather than owning it outright.

A volunteer lock-keeper, someone who grew up on a family boat, a crew who spent a week working locks together on a hire holiday — the plate reads the same to all of them, because the fifth line was never really about boats. It's about anyone who's used something communal and put it back the way they found it, on purpose, for a stranger they'll never meet — the same instinct behind a site plan amended in biro rather than reprinted clean once somebody notices it's wrong for whoever comes next.

Isn't printing somebody else's rules on your own shirt a strange thing to want?

No — using the lock is what makes the rule yours, the same way weather makes a promise everybody using a crossing has already agreed to share.

A ferry timetable that ends with its own caveat isn't somebody else's small print either, once you're the one waiting on the quay for the tide to cooperate. A lock's fifth line works the same way: it stops being an instruction from an authority the moment you've actually worked the gates, and starts being something you know because you did it.

Does it print well?

Yes — cast lettering with a riveted border is naturally a hard-edged, high-contrast print.

Keep the numerals and lettering raised and solid rather than softened, cream against dark teal with red reserved for the one line that earns it — the same restraint that keeps a painted trail mark legible after a season of rain: plain shapes, few colours, nothing that needs to survive as a gradient. Two inks and a rivet border are the whole design.

How do I get one made?

Describe your own plate at JustOG — the lines, the order, and which one gets cast in red. Pick a direction, drag the crop frame, see it composited on the real garment, and it's made to order and shipped.

Designs other people have published are in the shop.

Five lines cast in metal, and the last one is about a boat that hasn't arrived yet.