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BBC Scotland yesterday:

A faulty valve on a CalMac ferry led to a sudden and uncontrolled release of highly flammable methane gas last summer, BBC Scotland News has learned.The operator’s investigation found that 700kg of the gas – enough to fill a four-bedroomed house – was vented from the side of MV Glen Sannox over the space of 12 minutes while it was carrying 82 passengers from Arran to the mainland.

So much methane was released that some of it was sucked into a ventilation intake, setting off gas alarms in the ship’s generator room.While the risk of explosion is believed to have been low, CalMac described it as a “critical failure” in the gas fuel system and said lessons had been learned.

The propulsion systems for Glen Sannox were designed, supplied and commissioned by Finnish firm Wartsila, a world leader in liquefied natural gas (LNG) engines, who worked as subcontractors to the Ferguson Marine shipyard. Details of the incident have not previously been made public and have only emerged after a freedom of information request from BBC Scotland News.

https://www.bbc.co.uk/news/articles/c1mv50enz09o

This would, in other countries, be an astonishing amplification of a very low risk event.

I’ll deal with the: While the risk of explosion is believed to have been low, CalMac described it as a “critical failure” comment first.

Methane will explode only in the 5% to 15% but alarms will go off at 1% methane (20% gas vapour concentration) and 2% (40%) will lead to shutdown, nowhere near the explosive range. https://www.classnk.or.jp/hp/pdf/rules/amendments/e-Amendments/16.12.27/411_part_gf_e.pdf

Was there a shutdown automatically triggered by 40% LEL 2% methane cloud? No, engineers shutdown manually. so the risk of explosion was essentially zero.

Returning to the incident overall, this is closer to a layered safety system catching a component failure than to an uncontrolled disaster. A valve failed open and dumped a large volume of methane overboard. Gas was drawn into ventilation spaces and set off further alarms, and the crew isolated the leak by hand. Methane is lighter than air, so most of it dispersed rather than accumulating to explosive concentrations. An expert quoted in the piece said the detectors and automatic fuel shut-off appear to have done their job. https://www.bbc.co.uk/news/articles/c1mv50enz09o

A valve can fail open and still not produce a catastrophe if later safety layers work, as they did.

Finally 82 passengers on 3 June 2025? 82? Summer? The MV Glen Sannox can take 852, more than 10 times as many!

Sheesh! That’s a monstrous subsidy provided by the Scottish taxpayer, via that SNP Government, that some islanders never stop moaning about.

Help Talking-up Scotland keep going

Crowdfunder at: https://www.crowdfunder.co.uk/p/help-talking-up-scotland-keep-going

Or by direct bank transfer to: JOHN WATSON ROBERTSON Sort Code – 08-91-04 Account – 12266421