Reefer containers have a built-in refrigeration unit that holds cargo temperature in transit, whether chilled cargo such as fruit, vegetables and pharmaceuticals or frozen cargo such as fish, shrimp and meat. In Indonesia, reefers are vital for seafood and inter-island food distribution.
A reefer unit maintains temperature; it does not cool warm cargo. Cargo must therefore be pre-cooled before stuffing, and the container gets a pre-trip inspection (PTI) at the depot. Set point, temperature unit, ventilation and humidity must match across the booking, shipper instructions, the unit itself and the EDI data received by the ship.
On board, reefers can only go in powered slots, and total power draw is capped by generator capacity. Feeders and barges without plugs use clip-on gensets or power packs. Crew monitor temperatures and alarms at regular intervals or by remote monitoring until the box is handed over at destination.
Cargo characteristics
| Parameter | Typical range |
|---|---|
| Sizes | 20 ft and 40 ft high cube; heavier tare than dry boxes, so lower payload |
| Set point range | Usually ~−30 °C to +30 °C; chilled ~−1 °C to +15 °C, frozen −18 °C or colder |
| Power | 380/440 V three-phase plugs; a few kW per unit, highest during pull-down |
| Ventilation and humidity | Fresh air exchange (m³/h) and humidity setting for respiring chilled cargo |
| PTI | Pre-trip inspection of the unit by the depot or a technician before stuffing |
| EDI data | Temperature and reefer status travel in BAPLIE and drive allocation to powered slots |
Stowage & securing principles
Powered slots only
Running reefers go in slots with plugs, and the total is capped by plug count and generator power. Remaining powered slots are reserved for later ports.
Access to the unit
The machinery end must be reachable for crew to check displays, alarms and repairs. Deck reefers are often easier to monitor than hold reefers.
Away from heat sources
Avoid positions next to engine room bulkheads, heated fuel tanks, and DG boxes that must be kept away from heat or electrical sources.
Set point and data
The booking set point is matched against BAPLIE data and the unit reading at loading. Any difference is reported before departure.
Regular monitoring
Supply and return temperatures and alarms are logged at intervals or by remote monitoring. Time off power between terminal and ship is kept short.
Gensets on barges and feeders
Where the ship has no plugs, clip-on gensets or power packs are provided with fuel for the whole voyage plus a reserve.
Pre-loading checks
-
PTI valid and unit working
Why it matters: A unit failing at sea is hard to repair and cargo may spoil.
-
Set point and unit (°C/°F) match the booking
Why it matters: Wrong units or a missing minus sign are classic causes of reefer claims.
-
Ventilation and humidity per instructions
Why it matters: Respiring chilled cargo needs the right air exchange.
-
Cargo pre-cooled before stuffing
Why it matters: A reefer unit holds temperature; it does not pull down warm cargo.
-
Plug count and ship power for the whole rotation
Why it matters: Reefers from later ports also need powered slots.
-
VGM available
Why it matters: Boxes without a VGM under SOLAS VI/2 must not be loaded.
-
Genset fuel for voyages without plugs
Why it matters: A genset running dry means cargo without refrigeration.
Common risks
- Wrong set point or °C and °F mixed up.
- Reefers in slots without plugs or beyond power capacity.
- Warm cargo stuffed so the set point is never reached.
- Units out of crew reach for monitoring and repair.
- Too long off power during transshipment or at the berth.
- Barge gensets running out of fuel mid-voyage.
Frequently asked questions
What is a pre-trip inspection (PTI)?
A PTI checks a reefer unit before use: compressor function, sensors, alarms and the ability to reach a given temperature. Boxes with a valid PTI are less likely to fail mid-voyage.
Why are reefers often stowed on deck?
Many ships have more plugs on deck, and deck units are easier to monitor and repair. Reefers in holds need enough hold ventilation to remove condenser heat.
Does STOWAGE.ID set reefer temperatures or monitor reefers?
No. The planner allocates reefers to powered slots, checks plug counts and shows temperatures from EDI data. The container module is rolling out in stages, and its stability checks are shore-side planning; the class-approved onboard loading computer remains the official reference.
General guidance for education. Follow the vessel’s Cargo Securing Manual, the shipper’s instructions and the surveyor’s directions.
Shore-side planning & decision support. The class-approved onboard loading computer remains the official reference.