The deck log for October 22, 1967, ( Page 1 and Page 2 ) provides enough information to generally locate the area where the prisoner capture took place.
While the specific capture location was not recorded, there is sufficient location, course, and speed data to bound the capture to an area south and east of Hon Mat island. (See the data table below.)
The location is precisely recorded at 1200 noon, during the GQ and firing just before the search and capture. There is a period of unspecified maneuver from 1200 to 1224, followed by precise course and speeds to the start of search operations at 1310. Search maneuvers are also not recorded but I assume them to be limited to a relatively small area.
The charts on this page are not precise plots but illustratations of how the available information restricts the possible pick up location.
Maneuver Data from Deck Log for October 22, 1967
106-17.0 E 18-47.3 N
Assuming a maximum radius from the 1200 location defined by 24 minutes of straight line steaming at 20 knots, the shaded blue circle shows the possible locations that the 1224 maneuvers might have started.
Assuming neglible distances traveled during the search operations that began at 1310, the grey shaded circle approximates the possible locations that the prisoners might have been picked up.
Given anecdotal information that the WBLC's were destroyed after being observed exiting from a river mouth, I tend to guess that the more westerly locations closer to the shore make more sense.