What to check on a RoRo Ramp.
A roll-on/roll-off ramp is a hinged steel structure, stern, bow or side mounted, that bridges the gap between the quay or another vessel and the ship's cargo deck so wheeled cargo can be driven straight on and off without cranes. It is distinct from a simple access ladder or gangway in that it must carry rolling axle loads at highway-comparable weights, sometimes over a hundred tonnes for the heaviest units, while also forming part of the hull's watertight or weathertight envelope when closed and dogged down. On many vessels the…
What sets a RoRo ramp apart
A roll-on/roll-off ramp is a hinged steel structure, stern, bow or side mounted, that bridges the gap between the quay or another vessel and the ship's cargo deck so wheeled cargo can be driven straight on and off without cranes. It is distinct from a simple access ladder or gangway in that it must carry rolling axle loads at highway-comparable weights, sometimes over a hundred tonnes for the heaviest units, while also forming part of the hull's watertight or weathertight envelope when closed and dogged down. On many vessels the ramp doubles as the shell door, so its closing mechanism is treated with the same seriousness as any watertight door on the vessel.
Main components
- Ramp platform — the load-bearing deck plate, often with anti-slip surfacing and sometimes a foldable inner flap section for reach onto uneven quays.
- Hinges and pivot points — carry the full swinging weight of the ramp itself plus the rolling load passing over it.
- Hoisting wires or hydraulic cylinders — raise and lower the ramp between stowed and operating position.
- Locking and dogging arrangement — secures the ramp in the closed position and seals it against the hull opening.
- Hydraulic power pack — supplies the cylinders, usually with a manual backup pump for power failure at the berth.
- Position indicators and interlocks — feed the bridge or cargo control station so the vessel cannot get underway with a ramp not fully closed and locked.
Selection and sizing
| Criterion | Why it matters |
|---|---|
| Maximum axle and total rolling load | Sets plate thickness, hinge rating and hydraulic cylinder capacity. |
| Ramp angle at low and high tide, or between vessels | Determines usable length and whether an articulated flap is needed to keep the gradient driveable. |
| Corrosion allowance | Ramps sit in a splash zone and see constant wetting, so plate and hinge material need margin beyond calm-water calculations. |
| Hydraulic redundancy | A stern ramp stuck half open can block the only cargo access on the vessel, so backup pumping matters more here than on most hydraulic equipment. |
Regulations and class requirements
SOLAS Chapter II-1 sets specific requirements for RoRo cargo access equipment following incidents where bow and stern doors failed to seal, including indicator and alarm systems on the bridge showing the closed and locked status of every ramp, door and hatch cover that could let water into a RoRo space. Class societies survey the ramp structure, hinges and locking devices at intervals tied to the vessel's periodic survey cycle, with particular attention to the securing devices after any reported difficulty closing or sealing.
Typical faults
| Fault | Consequence |
|---|---|
| Worn hinge pins or bushes | Ramp misaligns with the hull opening, making a full watertight seal harder to achieve on closing. |
| Hydraulic cylinder seal leakage | Ramp creeps down under its own weight or loses lifting force partway through operation. |
| Locking device corrosion or seizure | Ramp can close but not fully lock, which the bridge indicator system is specifically designed to catch. |
| Damaged or worn seal rubber at the closing edge | Water ingress into the RoRo deck in a seaway even with the ramp mechanically locked. |
What to look for in a supplier
- Structural design verified for the vessel's actual maximum rolling load, not a generic rating.
- Hydraulic system with a manual or independent backup means of closing in a power failure.
- Indicator and alarm components compatible with the vessel's existing bridge monitoring system.
- Documented corrosion protection suited to a permanently wet, salt-laden environment.
Treat a ramp that closes slowly or unevenly as a locking problem until proven otherwise, not just a hydraulic one — an asymmetric seal is exactly the failure mode SOLAS indicator systems were introduced to catch before the vessel sails.