Canadian Hydrographic Service
Central and Arctic Region

CA573389 - Prescott/Ogdensburg


CABLES
The symbols for submarine and overhead cables do not differentiate between cables 
conducting electric power, often at high voltages, and other types of utility cables. 
Mariners are advised to exercise caution when passing under all overhead cables and 
to avoid anchoring or conducting seabed operations in the vicinity of submarine 
cables. The clearance of an overhead cable may differ from its charted value due 
to changes in atmospheric conditions, water levels and other factors. For additional 
information, consult Notice No.16 in the Notices to Mariners, Annual Edition and the 
appropriate volume of CHS Sailing Directions.

SPEED NOTE
Speed limits OVER THE BOTTOM in KNOTS are as follows:
- 13 knots from Iroquois Lock to  light buoy 137A.
- 11.5 knots from light buoy 137A to light 186.

THE GREAT LAKES  ST. LAWRENCE SEAWAY SYSTEM
For information regarding lock data, limiting vessel dimensions, and regulations governing 
the transit of vessels in the St Lawrence Seaway between the Port de Montral and Lake Erie, 
refer to the SEAWAY HANDBOOK of which a current copy must be carried on board all vessels 
transiting the Seaway.  A copy of the Seaway Handbook can be obtained from the St. Lawrence 
Seaway Management Corporation, Cornwall. 


 Fisheries and Oceans Canada 2015. Published by the Canadian Hydrographic Service. 
A licence is required from the Canadian Hydrographic Service (www.charts.gc.ca) 
to reproduce or distribute this work.

