Thursday, August 31, 2006

Critical comments on the findings of the Re-Opened Formal Investigation (RFI) into the loss of the trawler Gaul

Following a careful study of the report into the loss of the trawler Gaul published in December 2004, at the end of the RFI, (, a number of questions and objections as to its content and conclusions arise.

In essence, the inquiry concluded that human error on the part of the crew, shore maintenance staff and the vessel's owners was the cause of the vessel's loss.

In this post, it is suggested that what actually led to loss of the vessel was a design fault in the construction and arrangements of the duff and offal chute openings and their means of closure.

The RFI conclusions in brief

  1. That the Gaul capsized and sank in severe weather following undetected seawater ingress into the factory space. The water entered this space through two hull side chute openings[1].
  2. That each of these two hull side chute openings had two means of closure: an outer non-return flap valve and a hinged inner cover; and that both of these closures were open prior to, and during the loss of the vessel.
  3. That, as a result of inadequate shore-side maintenance, both outer flap valves had become seized in the open position due to corrosion in their hinges, and that they had been in this condition since the time of the vessel’s departure from Hull, 16 days prior to the accident;
  4. That the hinged inner covers had been left open and unsecured by the crew; and
  5. That, had the crew closed the inner covers, this would have been sufficient to prevent the loss of the vessel.


[1] These chutes facilitated the overboard discharge of duff and offal waste resulting from fish processing operations within the factory space.


The design fault

The duff and offal chute openings in the hull of the vessel were provided with a two-barrier closure system: an outer non-return flap (the strength barrier) and an inner cover (the leakage barrier), and these were both required to be closed in order to maintain the hull’s full watertight integrity.

Unfortunately, it can be demonstrated that the outer non-return flap arrangement, which was present onboard the Gaul was such that, in certain circumstances, the sea could act directly on the exposed free edge of this outer flap and push it open.
In such circumstancess, if the inner covers had also been open or had subsequently failed[2] , the seawater would have been able to enter the vessel unhindered.


[2] It should be mentioned here that the inner covers were neither designed nor intended to withstand, on their own, the forces of the sea


For a pictorial explanation of the design defect on the Gaul, please follow this link:

This shows that a slightly different design arrangement of the outer non-return flaps would have prevented the rapid flooding of the Gaul, even with the inner covers left fully open.

Possible causes for the loss of the Gaul

The Re-opened Formal Investigation came to the conclusion that the outer non-return flaps in the duff and offal chutes on the Gaul had been seized in the open position since the time of the vessel’s departure from port - this conclusion having been drawn from the fact that the flaps were found to be in the open position during the 2002 underwater survey.

The fact that the inner covers were also found to be open during this survey was ascribed to the crew’s failure to close them.

In his closing remarks the judge stated firmly that "no other possible causes remained open".

The document published HERE shows that not only was this incorrect but that there are other more plausible explanations for the loss of the vessel:

Other aspects and questions

Linked to the above issues, there are also a number of elements within the formal report which appear incorrect:

1. When defining the scope of ship classification, the formal report failed to include the Classification Societies’ responsibility for watertight integrity. The definition within the report reads:

Class/classification = covers the development and worldwide implementation of published rules and regulations which will provide for: 1. The structural strength and scantlings of all essential parts of the hull and its appendages; ......”
While the definition as per IACS – Quality management System requirements manual states in respect of “Classification service” point 1. that “The structural strength (and where necessary the watertight integrity of) all essential parts of the exterior boundaries of the ship or offshore installation and its appendages.”

Why was the alteration of this international definition necessary in the formal report?

2. The definitions provided in the formal report for weathertight and watertight properties read as follows:
Watertight – impervious to the passage of water, as applied to ship’s structure, closures and joints. A watertight opening is so constructed that when closed, it will prevent water under pressure from passing through, and normally incorporates a gasket.”
Weathertight – capable of being sealed to exclude water in normal sea conditions. A weathertight opening is typically designed to keep out rain and spray only.”

Whereas watertight and weathertight are terms that have agreed International definitions such that items which are categorised and accepted as watertight or weathertight need to meet strict requirements for construction, strength, material thickness, gasketing, hinges and securing clips (these are generally set by National or International standard).
Watertight means capable of preventing the passage of water through the structure in either direction with a proper margin of resistance under the pressure due to the maximum head of water, which it might have to sustain.”Weathertight means that in any sea conditions water will not penetrate into the ship.”
(SOLAS 1974 as amended, 1966 Load Line Convention and Torremolinos Convention 1977)

Why were the definitions for watertight and weathertight used in the report incorrect?

Thus, a weathertight fitting should be designed to withstand, in any sea conditions, water pressure and prevent the passage of water from one side only.
A watertight fitting, on the other hand, must, when closed, prevent the passage of water through an opening no matter which side is under pressure.

Since the adequacy and functioning of the ship’s duff and offal chute fittings was central to the investigation, has not their confusing definition been a serious failing?

Why have the inner covers of the Gaul’s duff and offal chutes been categorised throughout the report as being of a ‘watertight’ standard, whilst, in reality, the construction, strength and arrangement of these inner covers would not even meet the requirements that would be expected for ‘weathertight’ closures?

Watertight and weathertight fittings generally make use of rubber gaskets and clips (or bolts) to seal steel-to-steel joints and prevent the passage of water. Watertight fittings need many more bolts/clips than weathertight fittings.
The principle shortfall in the strength of the chute’s inner covers is related to their direction of opening when considered in conjunction with external sea pressure loading (full sea loading on the covers would only be resisted by 3 butterfly nuts, instead of the overlapped gasketed steel plating arrangement that is normally associated with a weathertight joint).

3. It is also stated in the report that: “it is not clear how the spindle could have been repaired or replaced should the need arise without burning off the balance weight from the connecting arms”
However, the construction drawings for the duff and offal chutes show quite clearly that the hinge, spindle, balance weight and connecting arms can be readily dismantled for maintenance, repairs or replacements. (?!)

4. Is it not the case that, if the inquiry had found that the Gaul had sunk due to a design defect, the victims’ families would have been entitled to compensation?

Extract from The Merchant Shipping (Convention on Limitation of Liability for Maritime Claims) (Amendment) Order 1998:

" 1. The limits of liability for claims other than those mentioned in Article 7, arising on any distinct occasion, shall be calculated as follows:
(a) in respect of claims for loss of life or personal injury,
(i) 2 million Units of Account for a ship with a tonnage not exceeding 2,000 tons,”

This would amount today to approx. 3m USD per life lost (1 SDR = 1.48727 USD)

For those who wish to read the full technical argument behind the above points, please visit the following site: