HMS Ark Royal

A ship that one of us helped build in the late seventies (together with her sister, HMS Illustrious):

FV Trident Stability - model testing

In a few days time  - more precisely on the 24th of May 2010 - the re-opened formal investigation into the sinking of FV Trident is due to reconvene.

In anticipation of that day we have read through the transcripts of evidence available so far.
In 2002 when the then Secretary of State for Transport, Mr Stephen Byers, ordered the re-opening of the Trident inquiry, we were advised that new and important evidence had been discovered that justified a new investigation into the vessel's loss.

However, after ploughing through more than 7000 pages of recorded oral evidence (from the 40 days of hearings in the Aberdeen Court), we have not been able to locate any new and important evidence!

We were also surprised to learn that, despite the technical expertise that is available to the court, the Advocate General found it necessary to seek external advice on one of the simplest concepts in Naval Architecture concerning ship stability.

AG - "It is true that raising KG is generally detrimental and lowering KG favourable and this applies to all vessels" - Do you agree with this statement Dr Schmitter? [...]
Dr S - Yes in general terms this statement is correct
AG - Right.
(Transcript of evidence of 12 November 2009)

For the benefit of those with an interest in trawler stability, we have prepared a short video clip (see below, split in two parts), which explains the significance of KG (VCG) to transverse stability. [1] [2]

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[1] KG is the height of the vertical center of gravity above the keel (also known as VCG)

[2] Unfortunately, on the Trident the VCG position was not accurately known because an inclining experiment had not been carried out.

Asking the PM

The dapper Number 10 YouTube channel is currently offering the proletariat in this country the chance to ask the PM questions (in video format) about the economy.

Wishing to take advantage of this unique opportunity, we prepared a short video clip (see below the better Dailymotion version) and confidently submitted it to http://uk.youtube.com/DowningSt.

Unfortunately, our clip, it seems, is not going to make it to the Prime Minister's attention.

Why? Probably, its content was not considered pertinent enough to economic matters, or, perhaps, too pertinent for its own good. Who knows?

Anyway, Downing Street has kindly sent us a reply to a related FOI request (you can see it here:

http://www.whatdotheyknow.com/request/corruption_investigation), on which we shall comment properly in due course.

Video Interlude

Russian trawler in storm. Excellent video clip, kindly provided by RuTube.

http://rutube.ru/tracks/880557.html?v=568383d214265ffcd7d718852064bc86

Photographic evidence

In our posts of 27 April and 05 May we provided photgraphic evidence from the 2002 underwater survey of the wreck of the Gaul showing damage to the closing arragement of the vessel's offal chute's inner covers. This evidence clearly contradicts the final conclusions of the 2004 Gaul RFI.
As previously advised, we are now presenting a video clip which contains further details on this subject, including a model of the offal chute's inner covers and their probable behaviour when subjected to seawater pressure.

Gaul - offal chute inner covers
Video sent by gadflymotion531

An old theory re-surfaces

At the beginning of December, a new book saw the light of the day. Fishing Explorer – authored by Ernest Suddaby, a former skipper of the Gaul, and published by Maritime Info UK Ltd - makes a very pleasurable read.
Put together with brilliant literary skill, printed in excellent graphic conditions and warmly prefaced by Alan Johnson MP, the book offers the reader a rich source of documentary information and photographic material.
The book carries two main narrative threads: one which depicts the author’s trip to the Falklands and one recounting his time as skipper onboard the Gaul, interspersed with personal memories and anecdotes.

In his account of the Gaul, along with his impressions and recollections of past events and more recent developments in the Gaul saga – many of which are well worthy of note - the author also shares with us his disagreement with the results of the 2004 Formal Investigation, and his personal opinions as to the causes that might have led to the loss of the vessel.In the author’s view, the sinking of the Gaul was caused by foul weather and bad luck, which led to flooding through the two fish loading hatches cut into the trawl deck. These hatches, it is suggested, could have been opened by the pull of gravity, when the vessel rolled beyond 90 degrees in heavy seas.

Mr Suddaby’s hypothesis is not that new, in fact it has been, if we may say so, previously enjoyed. It is what the results of the first formal inquiry, held in 1974, implied. The MAIB also flirted with this theory for a while, although, after the 2002 underwater survey and further reflection, they decided to abandon it. They did not, however, explain very well why.

Therefore, we have taken it upon ourselves to try and present the reasons why this loss scenario is merely a conception (so as not to say mis-conception) rather than a real possibility.
To elucidate matters, we have compiled the video clip below, which, in a simplified manner, attempts to show how the fish loading hatches on the Gaul would have behaved under various roll conditions. The model presented therein shows that gravity – which inexorably acts downwards at all times and circumstances - would have had the effect of keeping the hatch covers closed and prevented seawater from getting inside the ship, when the ship rolled to an angle of 90 degrees from its vertical position. The model also shows that, when the ship rolled beyond 90 degrees, the hatch covers would have still been kept closed by seawater pressure, and that this would have happened even without taking into account the effects of the hydraulic ram system, which was connected to the hatches.

Enjoy!

Back garden model testing

At the end of the 2004 RFI, the wreck commissioner opined: “[…] it is important to note that although both chutes were found on the wreck to be open both in way of the non-return flap and the internal top cover, there is no known mechanical reason why this was so.” [1]

This viewpoint has recently been echoed by the the Treasury Solicitor who said: “there was no evidence that the chutes had been forced open by wave or water action so this was not advanced as a loss scenario by the experts”

Having enjoyed the benefits of a sunny weekend, we decided to construct a small-scale (and cheap) model of the chutes and test them with a hose. The results of this simple experiment provide a clear illustration of the SCENARIO whereby the design fault in the duff and offal chutes on the Gaul caused the flooding and loss of the vessel.

Simple mechanics!

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[1] Report of the Re-opened Formal Investigation into the Loss of the FV Gaul

Back garden modelling of the Gaul chutes
Uploaded by gadflymotion531

The video file can be dowloaded from this SITE (2.9 Mb)

Investigation on behalf of the Attorney General

Body language

While waiting for an answer to our question about the ‘missing evidence’ (which, between us being said, was somewhat rhetorical), we decided to address another query to justice David Steel:

What recommendations, advice or expression of expectations regarding the Gaul case did the Attorney General and the DPM, John Prescott, offer you before and during the 2004 Formal Investigation?

© Crown copyright 2004

Another small observation

The 2004 Formal Investigation into the sinking of the FV Gaul concluded, as we all know by now, that the cause for the loss of the vessel was the ingress of a large quantity of seawater through the two duff and offal chutes openings in the hull of the vessel.
The double-barrier protections of these openings – the inner covers and the outer flaps - were found to be in the open position during the underwater survey in 2002.
The fact that the outer flaps were found open, the investigation concluded, was due to seizure caused by corrosion in the vessel’s 16 month old flap hinges and failure on the part of the crew and shore maintenance staff to identify and rectify this problem.
The fact that the inner covers were also found open was explained away by crew negligence. However, the trouble with these findings (as we have attempted to explain in our earlier posts) is that they were based on unsubstantiated assumptions.

Let’s take, this time, the presumed corrosion at the flap hinges. (For a few more details on this issue please click HERE.)
As the same combination of materials, mild steel and brass, had been used in a number of other structures on the Gaul (e.g. for the toggles and clips on all weathertight hatches and doors), one would expect similar corrosion problems in those areas.
In reality, though, this doesn’t seem to be the case.
Quite the reverse, as the following clips[1] show, even after 28 years under the sea, the toggles and clips on the Gaul did not present such a level of corrosion and seizure that would prevent them from being easily unscrewed by the ROV[2] arm.

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[1] Extracts from the 2002 MAIB video footage - © Crown copyright
[2] Remote Operated Vehicle

weathertight hatch mild-steel clips & brass bush

weathertight hatch brass toggle & steel toggle bolt


weathertight hatch brass toggle & steel toggle bolt