On Arthur's chart of the Sandheads the funnel shape is clearly mimicked by the buoyage and lightships; see the image at right, where the orange dotted outline is mine, but at each angle or kink the chart indicates the presence of either a lightship or a buoy. All the lightships are described as having lights 44 feet high with a visibility of 12 miles. Arthur states that all the lighships were manned apart from the Middleton. This is supported by the chart which only specifically mentions manning in so far as to state that the Middleton is "unattended" - presumably because Middleton was only a couple of miles from the shore and adjacent to Saugor Lighthouse. Across the mouth of the bay three lightships are shown. The westernmost, at bottom left, is called Pilots Ridge positioned at 20° 51.5’ N. and 87° 52.5’ E. The easternmost is Mutlah at 20° 57’ N. and 88° 34.5’ E. These two are about 40 miles apart and both are anchored in deep water. Roughly midway between the two is Eastern Channel lightship at 20° 59.5’ N. and 88° 12’ E. and anchored close to the southernmost part of the shoal water at the 60 ft. line. The size and visibility of these three lightships is such that any vessel approaching the Hooghly from sea should see one of them. From the different characteristics of each of their flashing lights their identity could be determined and thus the ship's position known and a course set to proceed inwards, if heading for Calcutta, to the next safe mark; that at the start of the funnel, the ‘Intermediate’ lightship, at 21° 13.5’ N. and 88° 12’ E., this being about 14 miles N. 2° W. from Eastern Channel lightship.
The Eastern Channel navigation seems pretty clear from the chart. North of the Intermediate lightship there is shoal water to both sides of the channel which, from Intermediate to Lower Gaspar, is about 6 miles wide and buoyed with pairs of buoys, port and starboard about 3 miles apart, the first pair being some 5 miles northwards of the Intermediate lightship. The course from the Intermediate was 14 miles N. 16° W. to the Lower Gaspar lightship. From the Lower Gaspar the next leading mark was the Upper Gaspar lightship 6½ miles N. 48° W. The channel, narrowing to about 3 miles, continued to be buoyed as before. In addition to shoal water constraining the channel, there are also sand banks with drying heights shown as much as 5 feet above the water at low water. These sand banks were Lower Long Sand to the west and Saugor Sand to the east. The last lightship, the Middleton, is another 4½ miles N. 12° W. from the Upper Gaspar and actually takes vessels over a narrow bar on Middleton Sand before deeper water to the north is shown west of Saugor Island and the prominent Saugor Light House standing 75 feet high on the eastern bank of the Hooghly and visible for 15 miles, but only 1½ distant from the centre of the channel. From there the channel is a clearly buoyed but tortuous route up shoal water into the centre of the river between many sand banks and in many places less than a mile wide. There were literally hundreds of buoys and navigation marks to maintain and keep in their correct positions - see next page for a fuller list.
The Western Channel looks equally tempting and if anything with fewer immediate hazards until North of Saugor Light. The main navigation leading mark is Kaukhali Light House, also standing 75 feet high but on the western bank of the Hooghly, and visible for 15 miles like its companion Saugor Light House some 13 miles distant across the river. This western channel seems less favoured on Arthur's chart but with no indication why. Maybe the lights and buoys were someone else's responsibility; maybe the channel north of Kaukhali Light fizzled out or was only tenable for small craft. My chart stops at the point where the Western Channel narrows to about ½ a mile between the shore and Upper Kaukhali Sand Bank in the river which blocks easy access to the Eastern Channel. I would imagine that the decision to go up the Eastern or Western Channel would have to be made before passing north of the Intermediate lightship. Thereafter it would be difficult and dangerous to change one's mind!
Also shown on the chart are a few other snippets of information indicative of what might have been current practice ca. 1910. One mile north of each of the lightships at Pilots Ridge, Eastern and Mutlah is a distinctive buoy; each is called "Station B" In the days before ship to shore communication was the norm [or even possible?] presumably the pilots had to be ‘on hand’ which meant bobbing about 40 miles off shore in the Bay of Bengal waiting for customers. Ship to ship or ship to shore communication when close would have been flashed by morse or semaphore or flags displaying the the International Code of Signals, visibility permitting. There is also printed information about the Pilots Station during monsoons. Three miles north of Eastern is printed "Pilots Station N.E.Monsoon" and about 4 miles south-west of Eastern is printed "Pilots Station S.W.Monsoon." Further information states that the S.W. monsoons are from mid-March to the end of October. No details are given about the N.E. monsoon which suggests a lesser event. Further advice is printed some seven miles north-west of Mutlah; Owners of vessels are strongly advised not to risk their vessels lying at anchor awaiting orders at the Sandheads between the months of April and November inclusive. Vessels are recommended to go into Saugor Roads where there is a safe anchorage and telegraph station. Finally the chart states that;The Pilot Vessel is fitted with wireless installation and communicates direct with Calcutta. I don't have any other charts, so have no information of what happened in the river itself from Saugor Island on the 120 mile or so trip to Calcutta. For a description of that see Hazards of the HOOGHLY. Thus the really intricate pilotage all happens off my chart.