Government of Canada

 

Single Failure Tankers and Newly Discovered Pollinators Under the Sea Received Dec. 23, 2016

Présenté par: Jim Ronback January 09, 2017
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Eel grass beds in river deltas are vital habitat for salmon
fingerlings, water fowl and other species. Has anyone determined if eel
grass (similar to tropical turtle grass) and other coastal flora are
also dependent on undersea pollinators(1, 2)?

If not, then we need to determine what is the impact of an oil spill on
the undersea pollination process before we allow tankers with hazardous
cargoes along our environmentally sensitive coasts, rivers and water ways.

A spill from supertankers carrying dilbit (diluted bitumen) can be
disastrous. Most loss of propulsion accidents occur when a vessel is
maneuvering, such as docking or anchoring facilities, rather than when
the vessel is traveling at steady speed. (7) How will these accidents
affect the ecology of the coastal foreshores?

Modern oil and gas tankers are very complex systems that can have many
failure modes. Almost all use only a single propeller and many have
only a single engine to drive it.
"Tankers require power for propulsion,cargo and ballast handling,and
other ship systems. Most tankers are single screw,powered by a single
slow speed diesel engine connected to a fixed pitch propeller. Over 30%
of tanker casualties are attributable to loss of propulsion or
steering. Therefore,tankers operating in particular sensitive regions
or otherwise requiring a high degree of redundancy and maneuverability
are often designed with twin screw propulsion systems.The major
classification societies offer notations for steering and propulsion
machinery redundancy." (5)

"... the current large (over 10,000 deadweight) tanker fleet is
experiencing at least two full losses of power or steering per day, and
probably more than ten. If this fleet were twin screw, properly
implemented, this number would be cut by a factor of one thousand. At
the same time, tanker low speed manueverability would be improved
dramatically. All this could be done for a net cost of less than that
of the double hull."(6)

Thus tankers are only a single failure from disaster if the propulsion
system fails. They are an accident waiting to happen.

When will the regulations be changed to require mandatory twin screws
for tankers transporting hazardous cargoes along our coast and in our
harbours and waterways?


Yours safely,

Jim Ronback
System Safety Engineer (retired)

1530 Kirkwood Road
Tsawwassen, BC
V4L 1G1

1) Meet the Newly Discovered Pollinators Under the Sea
The tiny crustaceans are challenging previous assumptions about how
plants grow underwater
By Erin Blakemore , smithsonian.com, December 5, 2016
http://www.smithsonianmag.com/smart-news/newly-discovered-bees-underwater-pollination-180961277/

https://youtu.be/B7VLBhQ-rQo Check out the video

2) Experimental evidence of pollination in marine flowers by
invertebrate fauna
Brigitta I. van Tussenbroek, Nora Villamil, Judith Márquez-Guzmán,
Ricardo Wong, L. Verónica Monroy-Velázquez & Vivianne Solis-Weiss
Nature Communications 7, Article number: 12980 (2016)
doi:10.1038/ncomms12980

3) The art of controlling an LNG carrier
KONGSBERG Gruppen
https://youtu.be/nEwqOtVtYgQ

4) Engine room of LNG vessel with Electric Propulsion (DFDE)
https://youtu.be/UDXrdgnyjZk

5) "Tankers require power for propulsion,cargo and ballast handling,and
other ship systems.Most tankers are single screw,powered by a single
slow speed diesel engine connected to a fixed pitch propeller.Over 30%
of tanker casualties are attributable to loss of propulsion or
steering.Therefore, tankers operating in particular sensitive regions
or otherwise requiring a high degree of redundancy and maneuverability
are often designed with twin screw propulsion systems.The major
classification societies offer notations for steering and propulsion
machinery redundancy."
http://marinewiki.org/index.php/Oil_Tankers

6) The Argument for Twin Screw Tankers
Jack Devanney, Center for Tankship Excellence, USA, djw1@c4tx.org
http://www.martrans.org:8093/symposium/papers/Track%20A/A11%20devanney.pdf

7) Nuclear Regulatory Commission Issuances: Opinions and Decisions of
..., Volume 7
By U.S. Nuclear Regulatory Commission , p661
https://books.google.ca/books?id=8h-u9oG8ou8C&pg=PA661&lpg=PA661&dq=loss+of+propulsion+and+maneuvering+in+tankers&source=bl&ots=AAt9rtYfEN&sig=oHfRGE9467TuOjxUMjdGMVMA2n8&hl=en&sa=X&ved=0ahUKEwjf5rymkuPQAhWLiVQKHUI5Dr0Q6AEIODAF#v=onepage&q=loss%20of%20propulsion%20and%20maneuvering%20in%20tankers&f=false


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