On Monday 1st July 1935 Crested Eagle ("The Greyhound of the River") was rostered to run from Tower Pier to Clacton and return later the same day.
Departure from Tower Pier was at 9am for Greenwich (9.30am), North Woolwich (10am), Gravesend West Pier (11am) and Southend (11.45am) with an arrival time at Clacton of 2.15pm. She was then rostered for a short afternoon cruise from Clacton before setting off again at 4.15pm for Southend (6pm), Gravesend (7.15pm), North Woolwich (8.15pm) and Greenwich (8.45pm) for arrival back at Tower Pier at 9.15pm
The distance between Tower Pier and Clacton is 65 nautical miles so to get there in five hours Crested Eagle had to maintain a speed of at least 13 knots over the ground without stops. Given that there were days when she would have been punching against a tide of 2 knots, and in some places 3 knots, both ways she would have needed to do at least 16 knots through the water to get there on time and 17 knots to build in enough slack to take account of the stops. So the boats running from London to Clacton had to be fast and that is why the Crested Eagle, was dubbed the "Greyhound of the River".
The steamers just couldn't afford to slow down except in exceptional circumstances if they were to keep to the timetable. The pier calls had to be slick too. A delay of just 5 minutes on each of the ten piers she called at during this day would have put her back by fifty minutes giving an arrival time at Tower Pier of 10.05pm instead of 9.15pm. A ten minute delay at every pier and she would not have got back until 11.05pm very nearly two hours late. Not surprisingly, in order to keep to the schedule, the captains were ever keen for the gangways to be pulled in at the exact sailing time for each pier with any passengers who arrived after that being left behind. After all, there were plenty of trains back to London for any who missed the boat.
As a result of all this speeding along claims for wash damage against these Thames paddle steamers were common as they sped on past quays and jetties with ships moored alongside them as well as lighters and other craft on buoys and sailing on the river.
Today the Port of London Authority takes a dim view of speeding on the river and imposes an advisory speed limit of 12 knots above Gravesend and a mandatory one of 12 knots above Margaret Ness which is to the east of the Thames Barrier.
It also controls and monitors all shipping movements on the Thames using AIS and radar and at a click of a mouse can tell how fast any vessel is going anywhere in their area. As a result Port Control London is apt to call a ship up on the VHF radio to tell them to slow down, or wait for another shipping movement or whatever.
Also in those far off days experienced captains and pilots on the Thames often crossed onto the "wrong side" of the river to take advantage of tidal back eddies. These are areas of water where the tidal flow is in the opposite direction to the main flow in the middle of the river at various stages of the tidal cycle. Crossing over to sit in these back eddies can therefore help to boost a vessel's speed over the ground when otherwise she would be pushing an adverse tide.
This process is well understood on European Waterways where vessels do it all the time signalling to other ships in the vicinity that they are crossing over onto the "wrong side" by hoisting a blue flag or, more normally today, by exhibiting a blue board which flips up into position by the captain pressing a button. Here on the Thames such manoeuvres are now banned by the PLA.
So, in today's increased regulatory framework, these Thames paddle steamers of yesteryear would have found it hard to keep to their tight timetable and provide any certainty of getting back home on time.