Lockmaster

Run the lock at Keokuk. Keep the Mississippi moving.

Puzzletimingkeokuk

Free, no download. Works on phones, tablets and desktops. Log in to save your scores.

About Lockmaster

Lockmaster puts you in the control house at Lock and Dam No. 19 in Keokuk, Iowa, the 1913 dam that turned the Des Moines Rapids into Lake Cooper. Boats pile up on both sides of the dam and the only way through is your lock chamber, which lifts or lowers them about 38 feet between the upper and lower pools.

Every lockage follows the real order. Open the gate on the side the boats are waiting, let them in, close it, then run the valves until the chamber matches the other pool and open the far gate to let them out. The gates only open when the water is level, and a gate will not close on a boat, so the rhythm is yours to read.

Small boats take one slot, towboats with barges take two or three, and the excursion paddlewheeler Keokuk Belle takes two and pays well. Each boat has a patience ring. Pack the chamber, keep it moving and chain productive lockages for a growing streak bonus. Three boats turned away ends the shift. There is a guarded bypass switch for emergencies, but forcing a gate on a big level difference floods the pool and swamps any small craft waiting below.

Shifts run through the seasons and the hours, from a spring morning to a winter night when the eagles come to fish below the dam.

Screenshots

How to play

You are the lockmaster at Lock and Dam No. 19 in Keokuk, Iowa. Barges, towboats, pleasure craft and the Keokuk Belle queue up on both sides of the dam, and the only way past is through your chamber. Open a gate only when the water matches, shut both, then fill or drain the chamber to carry the boats up or down 38 feet. Every boat has a patience ring. Keep them moving, chain full lockages for a streak bonus, and don't let three boats give up and turn around.

Tap the two gate buttons and the fill and drain buttons. On a keyboard use A and D for the gates, W and S for fill and drain, Space for the next valve move. P pauses and M mutes.

Levels and goals

Each shift has a boat goal that grows as you go: shift 1 is 6 boats, shift 2 is 8, and so on. Clear it to move on, and earn back a lost strike.

Tips

Read the readout on the control desk. It always tells you the next sensible move.
Watch the rings, not the clock. Serve the boat closest to turning away unless the other side can fill the chamber.
Running the chamber empty breaks your streak. Wait a moment for a second boat when it will fit.
Fill and drain take about seven seconds. Start closing the open gate as soon as the last boat is clear.
The interlock bypass (B on a keyboard) lets you open a gate before the water is level. A small gap only rocks the boats. A big one floods the pool and sinks small craft waiting there.