Getting aboard safely: a practical review of access and egress for jack-up barges

By Theo Cleave, engineer, MintMech

Ask anyone who has run a jack-up barge campaign what most often stops work, and the answer is rarely the work itself. It is getting people on and off the vessel. Access and egress is the single operation that touches every shift, in every sea state and it is usually the limiting factor for safe, productive operations. Specify it well and a campaign runs to plan; specify it poorly and the crew stands down, waits on weather or takes risks no one should be asked to take. This piece sets out the methods available and how to think about choosing between them.

Start with the environment

A jack-up barge is a deliberately broad term, a rigid-hulled platform that jacks clear of the water to give a stable working base for construction, installation, site investigation or accommodation. They span a huge range, from small modular work platforms assembled near site to large offshore units. The first decision is not which ladder to buy; it is understanding where the vessel will work.

The International Jack-Up Barge Operators Association (IJUBOA) groups operating environments into five categories, and each changes the access problem materially:

• Inland waterways – non-tidal rivers, lakes and reservoirs at a fixed level. Mobilisation is often the hard part (narrow channels, low bridges), but access onto the vessel is generally less complex once on site.
• Tidal rivers and estuaries – semi-enclosed water with a free connection to the sea, exposed to tides, swell, fast currents and tidal bores, with highly variable ground. Higher marine traffic and tighter local-authority management.
• Nearshore and coastal – surf zones and beachfronts, very shallow or even negative water depths, exposed metocean conditions and frequently isolated sites. Extended crew transfers, and small units without accommodation.
• Nearshore and coastal – tidal – the same, with the added twist that the barge may stand in water too shallow for a crew transfer vessel (CTV) to reach it or on dry land at low water. New hazards appear: scour around the legs in sand, leg holes and even members of the public.
• Offshore – harsh, persistent conditions, far from shore, deeper water and larger vessels. Living aboard becomes preferable to reduce transfers from twice daily to fortnightly, and operations are tightly seasonal, bounded by support-vessel limits (commonly of the order of 1.5 m significant wave height and around 22 knots).

Before mobilisation, the environment has to be assessed against the vessel and its support fleet: metocean reports and storm-survival data weighed against the operating limits of the barge and the CTVs; distance to the nearest port or safe haven; geology driving leg penetration, scour and preload; marine traffic, visibility and survey requirements; and the deck layout, load and crew skillsets against the persons-on-board limit. The access method is one output of that assessment.

The transfer chain: quayside to deck

Getting a person from shore to the working deck is a chain, and every link must be safe. It usually begins with a transfer from land onto the CTV, via a jetty or fixed-level access, a pontoon, a floating or incline system or a rigid ladder and only then to the barge. Where the asset is close enough to shore, a gangway can remove the CTV from the chain altogether.

In foreshore and shallow-water work, the ground itself becomes part of the method: conditions must be suitable at all states of the tide, which drives the class of CTV and any specialist recovery equipment. The point worth holding onto is that the weakest link sets the limit, a robust deck-access system is wasted if the quayside transfer onto the CTV is the part that stands the job down.

Why the CTV-to-barge step dominates

The transfer between the CTV and the jack-up is, across the board, the usual limiting factor for safe operations. It is also where the economics bite. A typical campaign runs 24 hours a day on two twelve-hour shifts with crew change ashore. On an isolated site with an hour’s transfer each way, that can mean roughly five hours a day of non-operational time. A medium jack-up on a nearshore site investigation can cost in the region of tens of thousands of pounds per day, so a closer transfer location or a faster and more robust access method, can save very large sums across a project’s life. Access is a safety question first, but it is a commercial one too.

The methods, and where each fits

There is no single right answer; each method trades cost, capability and conditions differently.

• Walk-to-work gangways (motion-compensated) – the gold standard offshore, hydraulically and dynamically controlled to compensate for relative vessel movement. Also the most expensive: it needs a large support vessel, significant power and deck space and is generally justified only on large, long-life installations.
• Standard gangways – used inland and nearshore where the barge sits close to a quayside, bank or another vessel, removing the need for a CTV beyond an emergency response boat.
• Level transfers – the CTV pushes onto the hull of the barge (lowered to the water surface) and crew step across to a marked access platform with adapted handrails. Slow if the barge has to jack down from working height, but potentially quicker and safer when it is already in the water and the barge provides an effective lee that steadies the CTV.
• Personnel transfer baskets and man-riding cages – both need a suitable man-riding crane and a fully certified lifting suite. Modern transfer baskets are self-righting and cushioned against impact, with secondary restraint and a wire-rope sail as good practice; rigid man-riding cages suit inshore and quayside use but are not normally for transfer onto a floating structure.
• Concertina and rope ladders – emergency use only, and demanding for the untrained. They are still deployed once a vessel is jacked to storm-survival height, as a durable, simple means of access when a vessel is left unmanned in poor weather – best practice being a lifejacket and/or fall-arrest system for any climb over a metre.
• Cantilever incline access ladders – a vertical winched ladder section with integrated fall arrest, paired with a self-adjusting incline stair that removes the need for fall arrest on the stepped section. This moves people quickly through the transition zone into the safe area of the CTV or deck. Ladder adjustment copes with large tidal ranges and jacked heights, and push-on bollards let the CTV locate its bow and hold station, running freely up and down with the swell while keeping contact. For much nearshore and inshore jack-up work, this class of system is the practical workhorse.

Where the cantilever ladder is heading

The cantilever incline ladder is worth dwelling on, because it is both common and historically under-engineered relative to what is asked of it. Current industry practice tends to assess these systems as generic “ladders”, which leaves real gaps: the cantilever’s specific behaviour, its horizontal and vertical springing, the way loads transfer into the pontoon connectors and the effects of CTV surge and pitch in swell are not well captured. A particular weakness has been that CTV impact loads are often calculated to the relevant docking standard in the horizontal direction only. The consequence is conservative vessel-weight limits, sometimes as low as a couple of tonnes, commonly around five, which in turn means smaller CTVs, lower metocean limits, more standing time and greater project risk.

The direction of travel is to engineer these systems properly rather than treat them as catalogue ladders: independent analysis of the impact loads (including the vertical and dynamic components, not just the horizontal), finite-element optimisation of the connection into the barge, automatic hydraulic locking pins with clear locked/unlocked indication for both barge and CTV crews, generous tidal and jacked-height range with multiple defined operating positions and proper guarding, rollers and adjustable railings through the transition zone. MintMech’s own JackLad is one example of this approach, a cantilever ladder re-analysed against a regional engineering review to justify a higher CTV impact rating (raising the working limit from around five tonnes towards 6.5 t), with hydraulic pin locking and a defined nine-metre range across twelve operating positions. The wider lesson is the transferable one: matching the access system honestly to the vessel and the loads it will really see lets operators use larger, more capable CTVs, widen the weather window and reduce the riskiest standing time.

The takeaway

Access and egress deserves to be treated as a primary engineering and planning decision, not a piece of kit chosen at the end. Start from the IJUBOA environment, work the whole transfer chain from quayside to deck, recognise that the CTV-to-barge step usually governs both safety and cost and choose the method, gangway, level transfer, basket or cantilever ladder, that genuinely suits the conditions and the vessels available. Where a cantilever ladder is the answer, insist that it is engineered for the loads it will actually meet. The safest campaigns are the ones where getting aboard was designed as carefully as the work itself.