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Gambia River 



LONG before the African Coast was sighted the blue of the 

 Atlantic changed to brown as the ship entered the mud-laden 

 water from the Gambia River spreading far out over the sea. 

 Later in the day the low-lying, dark green mangrove forests 

 could be seen stretching away to miraged vagueness on either 

 bow. The ship steadily closed the land and threaded the shallow 

 channels of the estuary before she turned southwards into the 

 river itself and came to anchor in the swirling brown waters off 

 the town of Bathurst. 



With the Mediterranean virtually closed, our convoys to the 

 East were taking the long route round the Cape. Bathurst lay on 

 the very flank of this route, an ideal base for escort vessels and 

 aircraft. But Dakar, which we had failed to capture from the 

 Vichy French nine months before, lay less than loo miles to the 

 north and at any moment the Germans might have flown in air- 

 borne troops and built up the defences of Dakar so that this 

 former French base, and not Bathurst, would dominate the 

 convoy route to the Cape. The defences and facilities for vessels 

 and aircraft must be built up at Bathurst so that she could meet 

 any threat from Dakar. 



There were no surveys whatsoever of the colony except the 

 old Admiralty chart ; hydrographic surveys were urgently required 

 for laying the controlled minefields, booms, navigational buoys 

 and beacons, while land surveys were needed for planning the 

 siting of the guns, airfields and barracks. Challenger had therefore 

 to pay as much attention to the topography as to the soundings. 



Short-cut base measurements were unacceptable in such a survey 

 where an extensive triangulation would have to be built up across 

 the wide estuary and onto the off-lying islands and up the winding 

 creeks through the mangrove swamps. So a base of 12,311 feet, 

 or just over two miles, was measured on the flat road leading 

 north-westward along the shore from the town. The two measure- 

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