Draft and Mast Height Restrictions
- If your mast height (air-draft) is less than 27 m (90') and your draft less than 4.1 m (13.5') you will have no issues entering or passing through the Bras d'Or Lakes
- If your mast is higher than 27 m (90') or your draft is more than 4.1 m (13.5') you will have to use the north entrance through the Great Bras d'Or channel to the lake and will be unable to enter St Peter's Marina.
- If your mast height is greater than 36 m (118') your boat will be unable to enter the lake.
Confusion exists concerning the height of these power lines. In 2006 the minimum charted height was reduced from 30 m (100') to 24 m (80'), and in April 2015 was revised to 27 m (90'). Boats still report the safe clearance to be closer to 30 m (100').
- There are two main entrances to the Bras d'Or Lake system. Both have height and draft restrictions.
- The north entrance has a height restriction of 36 m (118') under the Seal Island Bridge and a limiting depth of 10 m (33').
- The south entrance has a charted height restriction under the high-voltage power lines at Beaver Narrows of 27 m (90') and a limiting depth of 4.1 m (13.5') in the St Peters Canal.
- The third entrance is the Little Bras d'Or. This is restricted to power craft with an air-draft less than 6.4 m (21') and draft less than 3 m (10').
The Bras d'Or Lakes system comprises two bodies of water; the northern basin, Great Bras d'Or Lake, known as the "Little Lake" and the southern basin, Bras d'Or Lake, or the "Big Lake", connected by Barra Strait between the villages of Grand Narrows and Iona. At the strait, a bascule highway bridge and a swing railway bridge allow passage of vessels between the lakes. There are no overhead restrictions at the bridges, the channel through the bridges is 31.7 m (104') wide and the minimum charted depth in the centre of the channel is generally over 10 m (33') but the chart shows one spot depth in the centre of the channel of 8 m (26.2') beneath the railway bridge. The railway company ceased operations on this section of track in 2015. The railway bridge will rarely be closed.
In more detail, the main entrance from the north is through the Great Bras d'Or channel, passing through a dredged channel over Middle Shoal at the entrance to Great Bras d'Or, then passing beneath the Seal Island Bridge and under high voltage power lines at Munro Point.
The Middle Shoal channel is dredged to a minimum depth of 10 m (33').
The minimum charted clearance under the Seal Island Bridge is 36 m (118') .
Under high voltage power lines at Munro Point, the minimum charted clearance is 35 m (115') at the extreme eastern side of the channel, over 50 m (165') at mid channel, and over 100 m (330') at the western side of the channel.
The entrance to the Bras d'Or Lakes from the south is through St Peters Canal. The Tidal Lock at St Peter's is 91.4 m (300') long, 14.45 m (47.4') wide with a limiting depth of 4.1 m (13.5'). This lock is restricted to vessels of less than 82.3 m (270') in length. Power lines over the canal have a charted minimum height of 32 m (105').Beyond the canal, on the passage through St Peters Inlet from St Peter's to the open lake there is a charted height restriction under the high-voltage power lines at Beaver Narrows of 27 m (90').
Note: Mariners are advised to exercise caution when passing under all overhead 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.