Maximum Size

Part I - Conditions of Ships Seaway Practices and Procedures

Maximum Ships Dimensions - Section 3

(1) Subject to subsection (5), no ship of more than 222.5 m in overall length or 23.2 m in extreme breadth shall transit.
(2) No ship shall transit if any part of the ship or anything on the ship extends more than 35.5 m above water level.
(3) No ship shall transit if any part of its bridges or anything on the ship protrudes beyond the hull.
(4) No ship's hull or superstructure when alongside a lock wall shall extend beyond the limits of the lock wall, as illustrated in Appendix I.
(5) A ship having a beam width in excess of 23.2 m but not more than 23.8 m and having dimensions that do not exceed the limits set out in the block diagram illustrated in Appendix I, or overall length in excess of 222.5 m but more than 225.5 m shall, on application to the Manager or the Corporation, be considered for transit after review of the ship's drawings and, if accepted, shall transit in accordance with directions issued by the Manager and the Corporation.

Mininum Length and Weight - Section 4

4. No ship of less than 6 m in overall length or 900 kg in weight shall transit.

Overall Ship Dimensions - Seaway Notice No. 3 - 1999

8. Overall Ship Dimensions
a) In recent years the design of the superstructure of ships with machinery and accommodations aft has changed considerably and has generally resulted in an increase in the overall size of the afterhousing. As a result, the bridge wings, antenna masts and, in some cases, the samson posts or store cranes are outside the limits of the block diagram in Appendix 1 of the Seaway Handbook, should the stern of the ship override the lock walls when exiting the locks.

Masters and pilots must take this condition into consideration and exercise extreme caution when exiting locks, to ensure that the ship is maintained in porper lock alignment until finally passed and clear of all structures.

b) The Seaway has undertaken a review of the allowable dimensions of ships that transit the water and steps are being taken to formally revise the relevant section of the Seaway Regulations to change the maximum
permissible dimensions to the following:

Maximum ship beam changed from the current 23.16 metres (76 feet) to a maximum of 23.8 metres (78 feet).

Maximum ship overall length (O.A.L.) changed from the current 222.5 metres (730 feet) to a maximum of 225.5 m (740 feet).

Certain requirements must be met by ships greater than 222.5 metres (O.A.L.):

1. Ships must have a rounded sterm bar.

2. Ships must be equipped with adequately powered self-tensioning and self-rendering winches and fairleads at an approved location.

3. Adding to the O.A.L. will somewhat decrease existing margins with respect to distances to and from ship arresters. Locking of these larger ships will require special operating procedures.
These will increase the lockage time by 2 to 3 minutes.

4. Mariners must comply with special mooring instructions and procedures when proceeding through the locks.

As water levels, changes in seasonal conditions and ship design can hae an impact on the ability of Seaway locks to accommodate ships with larger dimensions, special consideration must be given in certain cases to ensure a safe and efficient transit for all users. Prior review and approval of ship plans are necessary for all ships in excess of the current maximum dimensions before permission to transit will be granted.

For further information regarding transit of ships with dimensions in excess of the current maximum permissible dimensions, please direct inquiries to:

Director, Marine and Operational Services
The St. Lawrence Seaway Management Corporation
202 Pitt Street
Cornwall, Ontario

Telephone No.: (613) 932-5170, Extension 3211
Facsimile No.: (613) 932-5204

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