The 1830s and 1840s saw a major improvement in the aids to navigation on Northumberland Strait and Hillsborough Bay. A black can buoy was in place at Fitzroy Rock to mark one known hazard by the late 1830s. The Bay was surveyed under direction from the Colonial Government in 1839 and a chart published in 1842. In 1841 Captain Henry Wolsey Bayfield transferred the headquarters of the Hydrographic Survey from Quebec to Charlottetown and quickly began to chart the Strait as well as the entire Gulf of St. Lawrence. In 1845 the colonial government commissioned the building of a lighthouse at Point Prim which showed the entrance to the Bay. The following year a chart of the Bay was published based on Bayfield’s survey.
Prior to this activity the only charts were those of J.F.W. DesBarres published in the 1780s and they contained little more detail than the information from the Holland survey in 1764, twenty years earlier. Since the Holland survey dealt with the land, the chart contained little marine detail and only a few soundings.

Detail from J.F.W. DesBarres Chart of the South-Eastern Coast of the Island of St. John. Published as part of the Atlantic Neptune ca. 1785. Detailed soundings are rare and many hazards are not shown.
One essential aid to navigation, then as now, was the series of published “Sailing Directions” or “Pilots” which added navigation details to the charts. These were often complied from the observations of ship’s captains. For example many of the observations on the navigation of the waters of the Maritimes are from the log of H.M. Sloop Ranger which was on fisheries patrol in the area in 1831. The Sailing Directions could be extremely detailed or frustratingly vague. An edition of 1810 said only this of Hillsborough Bay:
Hillsborough Bay is the finest bay in the island, and the River Hillsborough is a fine navigable river; but timber here is not plentiful. Before Charlotte Town in this river, there is good anchorage in from 6 to 9 fathoms.
We praise Bayfield for the excellence of his charts but the first edition of his Sailing Guide which includes Prince Edward Island, published by the British Admiralty in 1847 is a magnificent achievement and is as much a contribution to navigation as the charts themselves. He introduces the section on Hillsborough Bay thusly: “The numerous dangers it contains, having hitherto been very imperfectly known and represented have rendered its navigation extremely difficult to strangers in a large ship; but this will now be obviated, it is conceived, by the Admiralty Chart accompanied by the following directions.” He then goes on for a full ten pages describing the hazards of the bay and the directions for avoiding them.

Detail of Bayfield’s 1846 Chart of Hillsborough Bay showing Huntley Rock, Fitzroy Rock and Astyanyx Rock. Detailed soundings can easily be seen.
The sailing directions were a very marketable item and every ship, except perhaps those in the local coastal trade, would have had a copy for the area for which they were destined. Copies were published using Bayfield’s information with no regard for the copyrights of the Admiralty. There were English and American editions, both official and otherwise, as well as dozens of other editions, reprints, additions, improvements and condensations. A French-language of the Bayfield volume was published in 1864. One English version by hydrographer J.S. Hobbs published in 1855, had the remarkably comprehensive and descriptive title:

Part of the title page of an 1855 edition of Sailing Directions
A small sampling of the information contained (condensed from the Bayfield edition) follows:
Hillsborough Bay is the finest bay in the island; within it is the principal harbour and capital town of Charlotte Town, which is advantageously situated on the northern bank of the Hillsborough, where the deep water approaches nearest to the shore. The town is well laid out with squares and its streets at right angles; the houses are generally of wood, and the population about 5000. All kinds of supplies may be obtained here, and there is sufficient water in the harbour for the largest ships; and the Hillsborough River is navigable for large ships 7 or 8 miles above Charlotte Town; smaller vessels may go farther up: the shores are all well settled. It is high water full and change, at 10h. 45m. ; spring-tides rise 9 1/2 feet, neeps 7 feet. Ships generally lie off the wharves of the town, where the channel is nearly 10 fathoms deep and 280 fathoms wide.
Strangers or those unacquainted, when bound to Charlotte Town, should take a pilot; but in the event of not meeting one outside, the bay may be safely entered, and good anchorage will be found N.W. of Governor Island, until a pilot can be obtained. When entering the bay from the westward the leading mark is Pownall’s Point, just touching the north point of Governor Island, bearing E. by N. run in with this mark, until you see the Presbyterian Church , and as soon as it is in one with Block-house Point N. by E. 1/2 E. steer N.E. by E. or N.E. 1/2 E., according to the tide, until the west side of Government-house and Battery Point come in one bearing N. 1/2 E.; these latter marks lead up the deep-water channel to Trout Point, at the entrance of the harbour. If you cannot see the leading marks, keep along the southern and eastern edge of the St. Peter’s Shoals, in 5 fathoms, up to near the Spit Head buoy, then anchor.
When coming from the eastward at night, Point Prim Light must not be brought to the westward of N.N.W., to avoid the Rifleman Shoal; and Prim Reef should be rounded at 10 fathoms, in a large ship; smaller vessels may cross it in 4 or 5 fathoms. As soon as the light bears to the southward of E. by S. 1/4 S. , and in not less than 10 fathoms of low water, or with Point Prim E. by S. , you will be to the northward of the reef. The course across the bay must be north or N. 1/2 E. , in thick weather or at night; the object being to strike soundings on the southern edge of the bank off St. Peter’s Island, and following it to the north-eastward, in 5 fathoms , till about 1 1/2 miles within the Fitzroy Rock, where you may anchor off Governor Island, in good holding ground, and wait for daylight, or a pilot. In clear weather, your course from the outer end of Prim Reef, in 10 fathoms, will be N. by E 1/2 E., about 5 miles.
Except in areas where there was silting in the harbours or where sandbars and shoals shifted with wind and tide the hazards to navigation changed little over the years. Although published over 170 years ago Bayfield’s sailing guide could still be used today to bring a ship into safe harbour in Charlottetown.