At a working fire, water rarely comes from one engine. One engine is the base pumper, the attack engine the handlines come off. Others are supply pumpers that lay a line from a hydrant or relay water toward it. And water comes on minutes after a line is laid, not the moment it's drawn. Three marks record that on the board, and Water Supply and Secondary Water read them. Replay draws each lay and shows the water flowing from each line's Water on time.
Set an engine's Function
In edit mode, select a placed engine or quint on the map. The bar at the bottom of the map shows Function, with three choices:
- Base pumper: the attack engine. A water supply chain always ends here.
- Supply pumper: an engine that pumps water toward the base pumper, from the source or in a relay. A chain never ends here, so its water has to reach a base pumper, or an engine with no Function, for Water Supply to check.
- None: the unit counts the way it always has.
The Function is set for this incident only, because the same engine can be the base pumper at one fire and a supply pumper at the next. It stays with the unit when you move it, or remove it and place it again. Trucks and other units don't have one. A viewer sees the choice but can't change it.
Mark how a supply line was laid
Select the unit a supply line comes from and open the Apparatus tab. A supply line, one of 3 inches or more that isn't assigned a handline role, has a Laid by row:
- Choose the engine that laid the line. The list shows the engines and quints on the map, with the line's own unit first.
- Choose Lay-out, a reverse lay from the receiving engine to the source, or Lay-in, a forward lay from the source to the receiving engine.
- In Start, type when the lay started as mm:ss, or select mark to use the playhead's position.
When the lay is set, the app finds the receiving end, the end of the line at a unit other than the engine that laid it, and the row names that unit, for example "Lay-out from E224". It finds that end once and keeps it, so a unit that moves later doesn't turn the lay around. One end of the line has to be within 15 feet of another unit's center, or 25 feet at a relay's far end.
A first-due engine often lays in to its own intake: it stops at the hydrant, the end comes off its bed and wraps the hydrant, and the engine lays in to the fire and pumps from that line. When you choose Lay-in and no other unit is at either end of the line, the engine that laid it is the receiving unit, and the row reads "Lay-in to its own intake". When the line comes from that engine, the end at the engine is the end the line was drawn from; otherwise it's an end within 15 feet of the engine's center.
If no unit is at either end, or units are at both, the lay isn't set and a message says why. A Lay-out always needs another unit at one end.
Once the lay is set, choosing another engine or lay updates it. Clear Start to remove it. On a line with a lay, Time to target is when the engine finished the lay.
A line laid in to another engine counts differently from one laid out. It runs from its source straight to that engine: the engine that laid it only carried the hose, so its pump isn't on that line. An engine that laid in to its own intake receives the water and pumps, so it stays on its line. Hard suction is never laid, so it has no Laid by row.
Mark when water came on
Supply lines and hard suction have a Water on row. Type when water started to flow in the line, or select mark to use the playhead's position. A line has one Water on time, and a new time replaces the old one; in a relay, mark each line. Clear the field to remove it. Setting it doesn't log a timing milestone.
Once the time is set, the row also says which way the water flows in the line, as Watch the water flow describes.
When each time can fall
Each mark has to fit the order things happened in. A time that doesn't is refused, and a message says why:
- Start is at or after the moment the line went out, and at or after the laying engine was placed.
- Start is before Time to target and before Water on.
- Water on is at or after the moment the line went out, and at or after Time to target.
To start a lay before the line's or the engine's recorded time, change that entry's time in the event log first. The marks never move those entries.
What Water Supply reads
On the Tactics tab, Water Supply and Secondary Water read the three marks only where they're set, so a board with none of them checks exactly as before. Hydrants on the map describes the rule itself.
- A base pumper always ends a chain, and a supply pumper never does. One supply pumper that every chain passes through leaves Secondary Water unchecked.
- A line laid in to another engine connects its source straight to that engine, without the engine that laid it. A line an engine laid in to its own intake counts the same as a line with no lay.
- In replay, a line with a Water on time counts from that time instead of from the moment it was placed, so the boxes check when the water came on. A line without one counts from the moment it was placed. In edit mode, every line on the board counts.
Watch a lay in replay
On the 2D map and in 3D, replay draws each lay that has a Laid by engine and a Start time. From the moment it's placed, the engine that laid the line waits where the lay starts. At Start, it drives along the line you drew, and the hose pays out of its bed behind it.
- Lay-out: the engine waits beside the receiving engine, with its hose bed at the end of the line there, and drives to the water source. The line shows from the receiving engine to the engine's bed.
- Lay-in: the engine waits at the water source and drives toward the receiving engine while the hose pays out from the source. It stops one engine length short, so the two engines never overlap, and the last length of hose appears when the lay ends.
- A lay-in to the engine's own intake: the engine waits at the water source and drives the whole line to where it's placed on the board.
The lay ends at the line's Time to target time. Without one, it ends when the engine has driven the line's length at 15 miles per hour, and never later than the line's Water on time. When the lay ends, the engine takes its position on the board and the line shows whole.
The drive is a drawing between two recorded times, the start of the lay and its end. The app doesn't know the route the engine took or how fast it went, so it draws a steady pace along the line you drew. To replay a lay at the pace it took, mark its Time to target.
- With reduced motion turned on in your device's settings, nothing drives: the engine waits where the lay starts until the lay ends, and then takes its position, and the line shows whole.
- In edit mode, the board shows every line and unit where they finished.
- In Street View, the engine moves along the line, but the line shows whole.
Watch the water flow
On the 2D map, a supply line or hard suction with a Water on time shows water moving through it: blue arrows run along the line from the water source toward the base pumper. In replay, a line's arrows start at its Water on time and never before, so in a relay each line starts to flow at its own time. A line without a Water on time never shows arrows, and neither does a handline.
The app works out which way the water runs from what's on the board, never from the direction the line was drawn in, because a reverse lay is drawn from the engine back to the hydrant:
- A line with a lay runs toward its receiving engine. A lay-out runs from the source through the engine that laid it, a lay-in to another engine runs from the source straight to that engine, and a lay-in to the engine's own intake runs to that engine.
- Hard suction runs from the water into its engine.
- A line with a hydrant at one end runs away from the hydrant, and its arrows start at the hydrant. A hydrant at the same end as a base pumper doesn't count, because water never leaves a base pumper along a supply line.
- A line from one unit to another runs along the supply chain toward the base pumper or, with no base pumper, away from the water source. A line from the base pumper to a unit that can't pump, such as a truck's waterway, runs away from the base pumper.
For the arrows, the base pumper is the engine or quint whose Function is Base pumper. While no engine or quint on the map has that Function, an engine or quint with a handline off it counts as the base pumper, unless its Function is Supply pumper. A handline here is a line assigned to attack, backup, exposure or search. Setting a Base pumper anywhere on the map turns this off.
When none of these settles the direction, the line shows no arrows. The Water on row reads back what the map shows: "Flows to E224", naming the unit nearest the end the water runs to, or why the line has no direction, for example "No direction: its chain has no source or base pumper." When a line's chain runs both ways, or a base pumper stands at each end, the row also says what settles it: a Base pumper, the lay marked under Laid by, or one engine made a Supply pumper. Setting the attack engine's Function to Base pumper settles most of these.
The arrows show which way the water goes and nothing else. They move at one steady pace on every line, whatever the hose size, pump or pressure, and they don't show how much water flows or how long a line took to fill.
- In edit mode, the arrows stand still and point the way replay will run them, so you can check the direction before you replay.
- With reduced motion turned on in your device's settings, the arrows stand still in replay too.
- 3D and Street View don't show the arrows.
The app reads the direction from the board, so a few layouts read the wrong way:
- An engine at the fire parked beside a hydrant, with no handline off it and no Function, reads that hydrant as the source of a line coming in to it, so the arrows run back out along the line. Set the engine's Function to Base pumper, or assign its attack line, and they turn around.
- A line that carries water on from the base pumper to a quint's waterway or to another engine points back toward the base pumper, and so does any line past them.
- A tender that nurses the base pumper points away from it, the way a line at a fill site does.
Undo
Each change to a Function, a lay, or a Water on time is one step for Undo, and undoing it also takes its entry back out of the event log. Redo puts both back. A Time to target mark undoes the same way.