Designing a gangway takes more than picking equipment off a shelf. It's a safety-critical system that connects the dock to the vessel, giving workers a secure path on and off during product transfer. Get the design wrong, and you introduce risk at the exact point where footing matters most.
Tides change, vessel heights vary with cargo loads, and dock layouts vary from site to site. These changing conditions make it difficult for a single gangway design to meet every application. The right system accounts for load capacity, movement, materials, and site conditions before it ever reaches the dock.
Accounting for Tide and Vessel Movement
Vessels don't stay in one position. As cargo loads and unloads, a ship or barge rises and falls. This constant movement changes the height and angle between the dock and the deck. A well designed gangway needs to move with that shift, not just reach across it.
That kind of flexibility comes down to a few key design choices:
- Slope and incline limits. As vessel height changes, so does the walking angle. The design has to keep that incline within a safe range, since too steep a slope turns the walkway itself into a hazard.
- Telescoping or extendable sections. These let the structure lengthen or shorten as the gap between dock and vessel changes. This prevents gaps from becoming too wide to cross safely or a reach to fall short.
- Rollers on the dock side. Rollers let the base slide and adjust as the vessel shifts with load, current, or wake. This keeps the connection stable instead of forcing a rigid fit.
- Truss configuration. Bowed truss designs are often chosen for sites with wide variation in vessel height. Meanwhile, straight truss designs suit locations with more predictable, consistent conditions.
Choosing Materials that Hold Up in Marine Environments
Marine environments are hard on equipment. Saltwater, humidity, and constant weather exposure wear down materials faster than most industrial settings. A gangway built from the wrong material won't hold up long, no matter how well it's designed.
Material selection affects how well a gangway performs in harsh marine environments. Key factors to considerinclude:
- Corrosion resistance. Marine grade aluminum alloy resists rust and degradation from saltwater exposure. This keeps the structure reliable over years of use, not just months.
- Strength to weight ratio. Aluminum offers enough strength to handle heavy loads while staying light enough for portable gangways to be moved and repositioned by hand.
- Protective finishing. Anodized or powder coated finishes add a protective layer to the aluminum itself. This helps it resist pitting and surface degradation from long-term saltwater and weather exposure.
- Fastener and hardware selection. Bolts, rollers, and hinges need corrosion-resistant coatings too, since a weak point in hardware can undermine an otherwise durable structure.
Preventing Slips with the Right Deck Surface
Footing is one of the biggest safety concerns on a gangway. Wet surfaces, changing angles, and constant foot traffic all increase the risk of a slip, which is one of several marine safety challenges that come with working at height near water. The deck surface is the first line of defense against that risk, and industry guidelines for safe walking surfaces outline what a properly designed surface should account for.
A few design choices make the biggest difference:
- Slip-resistant coating. Applied to the walking surface, this coating improves traction in wet, icy, or oily conditions common at marine and loading environments. A surface is generally considered slip-resistant once it reaches a coefficient of friction of 0.5 or higher, a benchmark referenced across industry safety standards.
- Perforated decking. Small openings in the deck plate allow water, ice, and debris to drain through instead of pooling on the surface.
- Cleats and traction strips. Raised aluminum cleats add extra grip underfoot, especially useful on inclined sections where the angle already reduces stability.
- Deck width. A wider walking surface gives workers more stable footing and room to pass safely, especially when carrying tools or equipment.
Designing for Edge Protection That Fit the Application
A secure walking surface only goes so far without something to hold onto at the edges. Handrails and guardrails give workers a physical barrier against falling off the side of the structure, especially in conditions where footing is already compromised by motion or weather.
The right handrail configuration depends on the application, the load, and how much flexibility the marine access system needs.
A few factors shape that decision:
- Rail material. Rope handrails reduce weight and suit portable gangways. Alternatively, aluminum rails can be used for more rigidity, which is great for higher traffic applications.
- Top rail height. OSHA's guardrail standard calls for a top rail height of 42 inches, plus or minus 3 inches, giving workers a consistent, reliable point of contact.
- Mid-rail placement. A mid-rail positioned between the top rail and the walking surface closes the gap that would otherwise leave a worker exposed at knee or thigh height.
- Truss-integrated rails. Some truss gangway designs build the side rail height into the structure itself. This adds rigidity and reduces the number of separate components to install and maintain.
Preventing Stray Current with Electrical Isolation
When designing a gangway for petroleum or chemical terminals, there’s an additional hazard that should be considered in the design process: the stray electrical current between ship and shore. As vessels connect to a dock, the differences in electric potential can create current flow through metal contact points. In a flammable atmosphere, that current is a real ignition risk.
Addressing this hazard comes down to a few design choices:
- Insulating components. Non-conductive materials at key contact points break the electrical path between ship and shore. This can prevent the current from traveling across the structure and into grounding or cathodic protection systems.
- Bonding practices. Where isolation alone isn't enough, controlled bonding connections help manage current safely instead of allowing it to arc at an uncontrolled point of contact.
- Site-specific hazard classification. Facilities handling flammable liquids or gases need to evaluate electrical isolation requirements against their specific hazardous area classification. After all, the risk profile varies by product and terminal layout.
Built for the Conditions You Actually Work In
Safe gangway design comes down to getting every factor right at once: load, movement, materials, footing, and isolation.
At Carbis Solutions, we design and build custom gangway systems engineered for the specific conditions of your site, not a one-size-fits-all model. Our team works with you from initial assessment through installation to make sure your gangway holds up where it matters most. Reach out to our team today to start planning your site's access solution.