the extra deck nobody calculated

Problem statement

The international safety convention for passenger ships, SOLAS, does not apply to vessels on domestic voyages, and IMO estimates that "around 95% of ferry-related casualties" occur on those voyages — inland lakes, rivers and inter-island routes in countries such as Tanzania, the Philippines, Bangladesh and Indonesia, where the ferry is often the only transport. IMO adopted voluntary Model Regulations on Domestic Ferry Safety in April 2022 that require, among other things, an inclining test at completion of construction, an approved stability booklet on board, an assigned load line that must never be submerged, and that "all repairs, modifications and conversions shall be carried out under the supervision of the competent authority or a recognized organization." But a 2024 systematic review by World Maritime University authors finds that in many developing countries the vessels actually carrying passengers have been altered "driven by profit motives ... to augment passenger and cargo capacities," through "the installation of land engines, the adding of decks, the lack of available naval architects, the absence of ship stability diagrams, and falsified documentation," and are then routinely overloaded, which "significantly reduces a vessel's freeboard" and lowers metacentric height when passengers crowd upper decks. The unsolved problem is that the model rules presuppose an inspection regime — surveyors, naval architects, stability calculations, honest paperwork — that does not exist for exactly the fleet that kills people, so a competent authority has no practical way to know whether a modified wooden or steel domestic ferry is stable before it sails.

Why this matters

The review's authors count 97 percent of known ferry fatalities as occurring in domestic operations (citing Golden and Weisbrod, 2016) and describe overloading as "a direct cause of approximately 90 % of maritime accidents" in the sector's literature (a figure the review takes from two national studies — Indonesia and the Congo — not a global statistic); the 1996 MV Bukoba capsize on Lake Victoria alone "claimed up to 1,000 lives," with over 500 trapped inside the hull "as the ship capsized in calm waters." IMO's 2023 Kampala workshop counted 350 registered domestic vessels of 24 metres and above operating on inland waters in just seven eastern and southern African countries — and registration is itself incomplete, since "in developing countries, these vessels are not properly registered or named." Ferries in these settings are lifeline transport for people with no alternative, so the safety failure falls on the poor, and a single capsize can produce casualties on the scale of an air disaster.

What’s been tried and why it hasn’t worked

The regulatory scaffolding has been built twice: the 2015 Manila Statement urged states to act, and the 2022 Model Regulations give them model national law, with IMO now running regional workshops (Kampala 2023; the EU-funded SCOPE project in Indonesia, Malaysia and Thailand from 2025) and free e-learning. But the model regulations are voluntary, and their stability provisions assume the tools of classed shipping: an inclining experiment, an approved booklet, supervised modification. The review documents why that assumption fails on the ground — vessels are converted with no naval architect available; stability diagrams are absent; documentation is falsified; owners hold monopolies that let them "restrict new entrants" and "engage in strikes ... to avoid strict regulatory enforcement"; and enforcement bodies lack the surveyors and the political room to ground a lifeline ferry. Technical work exists — a 2015 study modelled a stability upgrade for a typical Philippine ferry (Vassalos et al.), and Indonesia is now prioritising modernisation of traditional wooden craft and centralised digital manifests to curb overloading — but these are engineering studies of individual designs or manifest systems, not a cheap, repeatable way for an under-resourced authority to verify the as-modified stability of hundreds of heterogeneous local boats. Passenger-counting and manifest reforms address overloading but not the altered hull under it.

What would unlock progress

The gap is a field-grade stability verification method for modified, non-classed vessels that a trained inspector (not a naval architect) can run at the pier: a simplified inclining or roll-period test with instrumented smartphones or a low-cost sensor kit, producing a pass/fail against a conservative criterion and a rudimentary loading table (persons per deck, cargo, freeboard) that can be posted on board — the load-line-and-persons-per-deck data the model regulations already require. The adjacent precedents are the rolling-period test long used as an approximate stability check for small fishing vessels, and the aviation practice of weight-and-balance envelopes that operators can check without engineers. Pairing it with a photographic modification register (Article 8 of the model rules requires modifications to be recorded) would let authorities triage which boats need a proper survey.

Entry points for student teams

A naval-architecture/mechatronics team could prototype a smartphone-based roll-period and inclining test kit, validate it against a known hull in a towing tank or on a small vessel, and produce the one-page loading placard the model regulations envisage; a design team could build the "modification register" workflow (photos, dimensions, engine data) for a lake-ferry authority and test its usability with inspectors; a policy team could map, for one country's fleet (e.g., Lake Victoria or the Philippine inter-island trades), which of the model regulations' 18 pre-departure checklist questions (question 7: "Is its stability sufficient per the stability booklet?") are actually verifiable with current staff and instruments. Relevant skills: naval architecture (intact stability), embedded sensing, human-centred design, maritime regulation.