Initially, the Committee`s work focused on the hydraulic

Initially, the Committee`s work focused on the hydraulic
CGU HS Committee on River Ice Processes and the Environment
18th Workshop on the Hydraulics of Ice Covered Rivers
Quebec City, Quebec, Canada, August 18th – 20th, 2015
Winter Navigation and the Frazil Problematic
François Rousseau1, Brian Morse2
Safety Inspector, Transport Canada Marine Safety & Security
Centre de Transports Canada, 401-1550, avenue d’Estimauville, Québec, QC, G1J 0C8
[email protected]
Professor, Civil and Water Engineering Department, Université Laval,
1065 avenue de la Médecine, Québec, Qc, G1V 0A6
[email protected]
Commercial ships navigating on the St. Lawrence River during the winter months are
prone to the clogging or the choking of their sea water cooling suction strainers by frazil
ice. Frazil ice is the collection of loose, randomly oriented ice particles in water. Frazil
ice resembles slush and sporadically forms in open, turbulent, supercooled water.
Frazil ice clogging the seawater
intakes is an event that constitutes
a very significant danger to the
vessel itself, to the waterway and
to the environment. This problem
can occur if ships are not properly
equipped and/or if crews are not
properly trained. The clogged
seawater intakes can cause a loss
of propulsion and these vessels,
losing their navigability, drift with
the current and can run aground
Clogged sea water strainer
Foreign crew wondering what is going on?
Ship going sideways under
Quebec City Bridge
These events can create a major incident. The
grounding of a vessel can cause the interruption of
marine traffic or damaged infrastructure (bridges,
docks, etc.). This leads to an economic impact with
the supply chain being cut-off or delayed. There is
also the concern that these grounding events could
result in serious environmental impacts through
potential oil spills.
The problematic of frazil ice is not fully understood. Events that trigger frazil ice are not
completely known nor are the concentration and geographical distribution of frazil ice on
the St.Lawrence River. Currently, there are no means are available for the stake holders
when and where these events may occur.
Transport Canada Marine Safety & Security’s (TCMSS) roles are to protect life, health,
property and the marine environment in the context of an efficient and sustainable marine
transportation system. During winter, all ships bound west of Les Escoumins pilot station
must be adequately equipped to prevent clogging of their sea water cooling suctions
strainers. TCMSS’s Quebec City district office screens ships to ensure that each one
meets the requirements. Targeting is done well before ships are entering Canadians
waters. Education and information is provided to ship crews, ship owners, and all other
stakeholders on a daily basis to ensure ships conform and crews are well prepare to face
winter navigation on the River. Ships not properly equipped to protect against clogging of
seawater intakes are prohibited from sailing west of Les Escoumins.
Knowing more about the characteristics of frazil ice, would help TCSSM to be more
effective in its response to the vessels which may be affected by clogging of sea water
strainers. TCMSS Quebec City District office together with Université Laval
(Département de génie civil et de génie des eaux) have been awarded a research project
from Transport Canada Transportation Innovation and Applied Research Centre. The
objectives of the project are:
 To determine the periods and weather conditions when frazil ice could clog the
sea water strainers of vessels transiting in the St. Lawrence River during the
winter season.
 To quantify the heat required (volume flow of the ship’s warm sea water returning
to the suction) in order to ensure no frazil blockage.
 To help TCMSS to communicate best means, methods and practices regarding
frazil ice blockage prevention and to inform stakeholders about periods of severe
frazil conditions that could lead to frazil ice blockage occurrence in the St.
Lawrence River as well as other areas where frazil can also affect the safety of
navigation (i.e. Chaleur Bay, the Gulf of Saint Lawrence and the Atlantic).
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