The **active rig area (A)** answers what can operate now. Only a physically mounted part can receive links or act. The **shared carrying capacity (C)** answers what comes on the expedition. Active parts, inactive parts, canisters, objective objects and loot each occupy that total once. Mounting a carried part does not count it twice; moving it inactive frees A but not C.

This page uses **10 C** and an opening **4 A** rig. The four starter parts cost **1 C / 1 A** each. A canister costs **2 C** whether full, partial or empty; Fork costs **1 C / 1 A** when active; the isolation bridge costs **2 C / 0 A**. [Mechanical Interfaces And Opening Quantities](/Hold%20The%20Flood/Mechanical%20Interfaces%20And%20Opening%20Quantities) owns the complete quantity sheet and operating limits.

Worn suit functions—the integral oxygen tank, navigation, journal and emergency cutter—sit outside both totals. They cannot be dropped, sold, linked into the rig or converted into spare space. The cutter is a deliberate close-range tool for cutting work and desperate defence, not a second automatic weapon.

Capacity is checked before pickup, fixture retrieval or departure. If the object will not fit, the action refuses before commitment and leaves it visibly where it was. A deliberately dropped object stays at its recorded station location. A part installed in station infrastructure stops using C and A, works only through that fixture's visible rule and remains there until the same instance is reclaimed. Home fixtures stay aboard; a lent part can be reclaimed safely before departure, turning off that fixture's function rather than consuming or duplicating the part.

Compatible links among accessible mounted parts can be changed in the journal. The journal fully pauses enemies, oxygen, readiness and action progress. It does not perform physical work: pickup, dropping, mounting, removal, fixture use and oxygen transfer all happen while the game runs. Ordinary weapons mostly fire themselves when their own source, target and readiness allow; the player uses manual controls for labelled specials such as Barrier, Nozzle or a stored discharge.

The suit tank is the active breathing supply. This page uses a **12 O** suit tank, **8 O** ordinary-full canisters, **12 O** bench-prepared canisters, base breathing of **1 O per 30 seconds**, and transfer of up to **3 O per 30 seconds** while breathing continues. A canister is reserve gas, not a second tank that drains automatically.

To use one, the player deliberately couples it to the suit while the world continues. In this proposal, a carried vessel stays coupled during walking and ordinary automatic fire. A manual special or station operation that needs the occupied control interrupts the transfer; the same visible interruption rules below still apply. Opening the journal freezes the transfer along with everything else. The display shows exact suit oxygen, the selected vessel's oxygen, transfer progress and carrying use. A player-set reserve marker defaults to **4 O**, but it is only a warning level: it never estimates the route or orders an automatic return. Damage alone does not cancel transfer. Explicit cancellation, displacement out of reach, loss of the coupling or another occupied control can interrupt it, preserving exactly what has moved.

One boundary example shows the rule. Starting at **11 O** in the suit and **5 O** in the canister, after 15 seconds the suit reaches its 12 O ceiling: 0.5 O was breathed and 1.5 O moved, leaving 3.5 O in the vessel. Transfer stops immediately. If another 15 seconds pass, breathing lowers the suit to 11.5 O while the canister remains at 3.5 O. Gas is neither duplicated nor discarded at a ceiling, empty vessel or interruption.

Aboard the ship, unlimited oxygen provides free **ordinary refill** to the suit and raises a canister only as far as 8 O. Refill may stop and resume at an honestly shown partial amount. A commissioned packing bench can raise an eligible vessel to 12 O **prepared-full** without changing its 2 C size. That improved fill belongs to the vessel and remains if the lent bench part is reclaimed. If prepared gas is used, ordinary refill never recreates that four-unit surplus: below 8 O it fills to 8; above 8 O it neither vents the remainder nor tops it back to 12. Another completed bench cycle is required.

Oxygen stays separate from combat resources. Transfer does not heal condition, ready a weapon, refresh a barrier, create a trigger or fill a Capacitor. Time passing while the game runs may let an independently recovering part become ready, but the oxygen did not cause it.

This pressure is useful when another thirty seconds might reveal a clue, finish a physical task or make room for a startling find. It becomes annoying busywork if the player is repeatedly coupling vessels when no real choice changes, or if exact arithmetic pretends to certify a route. Clear state, incremental conservation and free home refill are meant to keep the decision on **what is worth risking now**, not on avoiding hidden loss.

The opening choice above contrasts one canister and four free spaces with two canisters and only two. Later, the same trade becomes sharper because the game still allows a ridiculous build.

Compare two loadouts aboard the **same eight-space rig with the same available parts** (8 A / 10 P):

| Packing choice | Equipment and air | Room left for a find |

Regular fighting provides temporary combat growth, alongside major transformations. They reset whenever the astronaut returns aboard, alive or revived. Combat areas refill for each new expedition, while completed permanent changes such as unlocked doors and joined rooms remain. That gives each trip another climb toward spectacle; see [Combat Rules](/Hold%20The%20Flood/Combat%20Rules) for growth and renewed encounters. The physical parts and knowledge that enabled the build remain, so packing still expresses a plan rather than erasing progress.

Voluntary return and death use the same carried manifest:

- The worn suit, active rig, inactive carried parts, canisters and newly acquired carried loot come aboard once, preserving their last completed object and fill states. Oxygen already breathed and explicitly consumed material stay spent; free ship refill happens afterward.

- How renewed enemy placement works around permanent changes; any other living-return world changes remain open.

- The exact cadence and presentation of regular combat growth and major transformations.

These rules are untested; numbers are proposals.