Internal Ramp
An internal ramp connects two cargo decks inside the ship rather than the ship to the shore, and unlike a stern or side ramp it never needs watertight closure - its job is purely structural, moving vehicles between decks quickly enough not to become the bottleneck in a RoRo ship's turnaround.
What to check on an Internal Ramp.
4 models from IMM Marine in Internal Ramp. Below: the full model list.
What sets an internal ramp apart
Stern, bow and side ramps all cross the ship's shell and must close watertight; an internal ramp sits entirely inside the hull, linking one cargo deck to the one above or below it, and is judged purely on structural capacity and traffic flow rather than sealing. Some are fixed inclines built into the ship's structure, others are hoistable or hinged so they can be raised clear of the deck below when that space is needed for taller cargo. On large car carriers, the internal ramp network, not the shore ramp, is usually what limits how fast a full load of vehicles can be driven aboard.
Legend
- upper deck
- hinge
- stowed (raised) position
- ramp panel
- lower deck
Main components
Ramp deck structure
An inclined steel deck, stiffened underneath by girders sized for the axle loads and traffic density the ship's cargo plan expects on that route between decks.
Hinge and lifting arrangement
On movable designs, pivot points at the upper end and a hydraulic or wire lifting system at the lower end, allowing the ramp to fold up against the deckhead above.
Read the full guide
Locking supports
Fixed props or pins that carry the working load once the ramp is lowered, so the lifting gear is not left holding vehicle traffic loads continuously.
Surface treatment
A non-slip deck coating or pattern plate, since the ramp incline combines with ship motion at sea and wet tyres in port to create a real slip hazard for drivers and stevedores.
Selection and sizing
| Parameter | Relevance |
|---|---|
| Incline angle | Steeper ramps save deck length but limit the ground clearance of vehicles that can use them |
| Load rating | Must match the heaviest vehicle class the deck it serves is designed to carry |
| Fixed vs movable | Movable ramps trade flexibility in deck height for added hydraulics and maintenance |
| Width and traffic pattern | Single or dual-lane ramps set how fast a deck can be loaded or cleared |
Regulations and class
Internal ramps are assessed under class structural rules as part of the RoRo deck system, sized for the vehicle loading the deck plan specifies, with fatigue considerations for the constant traffic they carry over the ship's life. Because they are enclosed within the hull they do not fall under the watertight door provisions of SOLAS Chapter II-1 that apply to shell openings, but class surveys still check the structure, locking supports and, on movable ramps, the lifting mechanism for wear and correct operation.
Typical faults
- Locking support wear - worn pins or props let the ramp settle slightly under load, transferring repeated shock into the hinge and lifting gear instead of the fixed structure.
- Corrosion under the deck coating - trapped moisture beneath a worn non-slip surface corrodes the plate from underneath while the top still looks serviceable.
- Hinge seizure on movable ramps - infrequent operation lets salt and grime dry into the pivot, and the ramp resists the first lift after a long period in one position.
- Surface wear at the transition edge - the join between ramp and adjacent deck takes the highest impact loading from vehicle axles and wears faster than the rest of the ramp.
What to look for in a supplier
- Structural certification tied to the actual vehicle mix and traffic density the deck plan specifies
- Non-slip surface system with a known service life and a straightforward re-coating procedure
- For movable ramps, independent locking supports rather than reliance on hydraulic pressure to hold position
- Reference installations on comparable RoRo tonnage, since ramp geometry has to work with the specific deck heights of the ship
Inspect the transition edge between the ramp and the fixed deck at every opportunity - it takes the worst combination of impact and wear on the whole ramp system and is where cracking typically starts first.
Models in this type.
The best-documented model of each manufacturer first, then the next — 4 of 4 models in Internal Ramp. Every row links to full specifications, documents and service notes.
Manufacturers.
All 4 manufacturers with models of Internal Ramp. Names with a manufacturer page open it; the others open a search across the full library.
All manufacturers in the libraryAlso in RoRo Equipment.
The other equipment types in this category.
Write to us about this model — the answer comes by e-mail.
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Questions that come up with this equipment.
Is Internal Ramp data free?
Yes. Every model page, every guide and every datasheet for this type is readable without an account. An account adds saved searches and requests, nothing is taken away.
My model is missing — what now?
Send us the nameplate. We identify it by hand, add it to the library, and if you need a part or a service, the request is already on our desk.
Can you source a Internal Ramp part?
Yes. Tell us the manufacturer, the model and what you need — a person reads every request and replies by e-mail.