Comments on: LNG ship at anchor

By: Kerry-Anne

Kerry-Anne — Wed, 08 Apr 2009 10:18:50 +0000

Johnny, thanks so much for taking the time to explain all of that – you’ve given us some really great information, and hopefully it will put some people’s minds at ease!

By: Johnny B

Johnny B — Tue, 07 Apr 2009 22:18:17 +0000

I work as officer on these ships, and I can tell you they are extremely safe. The spherical tanks that hold the liquified gas are made of aluminium which has a very low crack propagation property at cryogenic temperatures. There are gas detectors in each hold which surrounds the tanks are constantly analyze the atmosphere to give warning of any loss of containment. The tanks are not pressurized and the boil off (cargo evaporating) is burned in the engine room boilers. They stay off Cape Town for long periods probably because they are waiting for cargoes to become available in various parts of the world and South Africa is a good central location to hang around waiting for a cargo.
LNG or liquid methane (CH4) is quite a light cargo so these ships don’t draw large draughts like VLCCs (supertankers) and the draught doesn’t change that much from loaded to ballast condition.
Hope this clarifies some of the questions about LNG carriers.
All the best folks
JB

By: Paul

Paul — Wed, 18 Feb 2009 20:43:48 +0000

Thanks for the info Wayne,

The following article explains the consequence of a LNG leak in layman’s terms: http://www.marinefirefighting.com/Pages/Newsletters/Newsletter.htm

In a nutshell, the article explains that there’s a reasonably small chance that it would ignite, and if a severe catastrophe occurred and the liquefied gas came into contact with water, it could explode, though would not ignite (if I understand the article correctly). The explosion would be detrimental to people and buildings nearby. I’m not sure about the 55 atom bomb thing though… in fact, I seriously doubt this.

If LNG came in contact with air only and were ignited by a bare flame, and was in a 5%-15% mixture with air, then it could ignite and would burn rapidly. It would likely be burned out before fire-fighters arrive on scene. Remember that this gas isn’t stored under pressure… it’s not like a balloon waiting to pop.

In conclusion, I guess there could be a danger involved… as I suppose there is danger involved in transporting petrol along the road in tankers. This said, I’m glad that the LNG tanker seems to keep it’s distance from the shore – just in case.

By: Wayne meyer

Wayne meyer — Wed, 18 Feb 2009 16:53:06 +0000

Hi All

I hope that all of you know what this ship carries. LNG is some of the most explosive substance known to man kind. If this gas (stored at -160 degrees celcius) meets oxygen (air) it ignites causing an explosion which decimates everything within a 5 km radius and is the strength of 55 Hiroshima Atom bombs.
These guys are bringing this gas within harmful reach of our coastline and most people don’t even know what it is. If you are not convinced go to http://www.revag.co.za or search timrileylaw .

Regards

Wayne

By: LNG tankers off Cape Town | alistair.pott

LNG tankers off Cape Town | alistair.pott — Thu, 29 Jan 2009 06:52:26 +0000

[...] often have ships like the one picture above (source) berthed off Cape Town. Because of their conspicuous appearances they generate a lot of [...]

By: Paul

Paul — Fri, 23 Jan 2009 20:50:27 +0000

Kai you make two very good points. I can’t work it out myself.

By: Kai

Kai — Thu, 22 Jan 2009 22:04:29 +0000

I see it every day. What more interesting is:

- it is not empty because it is in the water up to the marking line
- why does it stay so long there (at least 5 weeks).