FLOATING DOWN THE RIVER

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THE RIVER THAMES - FREQUENTLY ASKED QUESTIONS

	How long is the River Thames?
	How deep is the River Thames?
	How wide is the River Thames?
	How much water passes over Teddington Weir?
	How many boats are there on the River Thames?
	Do I need to register or licence my boat to take it on the River Thames?
	Where can I get registration documents to take my boat on the River Thames?
	How much will the Annual Registration Fee be on the River Thames?
	I am new to boating. Can you give some advice on what type of boat to buy for the River?

Question: How long is the River Thames?

Answer: In total, the River Thames is 344 km (215 miles) long from its source to the sea and is navigable for 306 km (191 miles) from Lechlade, which is the practical limit of navigation (the official limit of navigation is Cricklade some 18 km (11 miles) upstream).

The non-tidal Thames stretches for 237 km (147 miles) from the source to Teddington. From Cricklade, the limit of the Environment Agency's jurisdiction for navigational purposes, it is 218 km (135 miles) to Teddington and from Lechlade it is 200 km (124 miles).

The tidal Thames has a further 109 or so kilometres (68 miles) to go, through London and beyond, before it becomes the sea. However, it is quite difficult to define this point but the figure of 344 km (215 miles), quoted above as the total length of the River Thames, is calculated using the former (prior to 1964) seaward limit of the Port of London Authority as the point at which the River becomes sea. This former limit was on a line drawn between Havengore Creek on the Essex Coast and Warden Point on the Kent Coast. This point in mid-channel was, until about1915, marked by the Nore Lightship and hence the reference in many publication to the “Nore” as being the limit of the River. This point is now the approximate position of Sea Reach No1 Buoy which is a very appropriate name.

Seaward Limit of the River Thames

Some publications mention the Nore Sand as being the end of the River. This is a shallow area of water off the Kent coast approximately on a line between Shoeburyness on the Essex Coast and Sheerness on the Kent Coast. If this point is used as the end of the River then the length of the River Thames would be about 210 miles the figure mentioned in some encyclopaedia.

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Question: How deep is the River Thames?

Answer: Below Teddington the River Thames is tidal and therefore the depth of water is always changing. It is even difficult to state the depth of water at high and low tides as the height of these tides are not the same each time. It depends on whether they are Spring or Neap tides or somewhere in between.

Spring tides occur every two weeks about two or three days after a new or full Moon when the Sun and the Moon are pulling together. At Spring tides the high water levels are at their highest while low water levels are at their lowest. The tidal range (the difference between high and low water) is at its greatest. The average of all Spring high water levels is known as Mean High Water Springs (MHWS) while the average of all the low water levels at Spring tides is known as Mean Low Water Springs (MLWS).

Diagram of Definitions

Neap tides also occur every two weeks about two or three days after the Moon is in its first and last quarters but when the sun and the Moon are at right angles to each other. At neap tides the high water levels are at their lowest while low water levels are at their highest. The tidal range is therefore at its smallest. The average of all high water levels at neap tides is known as Mean High Water Neaps (MHWN). The average of all low water levels at neap tides is known as Mean Low Water Neaps (MLWN).

One other term that is used is Chart Datum (CD). This is the level of water shown on charts from which the charted depth and height of tide at any particular time is measured. If you add these two figures you get the Depth of Water at that time (see diagram). CD is the lowest predicted level of low water at Spring tides and is called the Lowest Astronomical Tide (LAT).

Now to get back to the original question. How deep is the River Thames?

In the estuary the charted depth (which can for most general purposes be considered as the depth at low water) is about 20 metres at its deepest . To get the depth of water at Mean High Water Springs (MHWS) you can add about 5 metres to that depth. At Mean High Water Neaps (MHWN) you only need to add about 4 metres.

Opposite Southend the charted depth is about 11 metres. Add about 5.7 metres to get the depth of water at MHWS and 4.8 metres at MHWN.

At Tilbury the charted depth is about 9.8 metres. Add about 6.4 metres to get the depth of water at MHWS and 5.4 metres at MHWN.

At Woolwich the charted depth is about 6.5 metres. Add about 7.0 metres to get the depth of water at MHWS and 5.9 metres at MHWN.

At London Bridge the charted depth is about 1.8 metres. Add about 7.1 metres to get the depth of water at MHWS and 5.9 metres at MHWN.

At Westminster Bridge the charted depth is about 1.9 metres. Add about 6.8 metres to get the depth of water at MHWS and 5.6 metres at MHWN.

At Hammersmith Bridge the charted depth is about 1.4 metres. Add about 5.7 metres to get the depth of water at MHWS and 4.6 metres at MHWN.

At Richmond the charted depth is about 1.0 metre. Add about 4.9 metres to get the depth of water at MHWS and 3.7metres at MHWN.

On the navigable section of the Non-tidal Thames (Teddington to Lechlade) the depths range from about 3.0 metres to 0.9 metres. The depth of water is controlled by the Environment Agency (EA) by adjusting the height of the weirs. The EA also endeavour to maintain a minimum dredged depth on the non-tidal River. It is not a constant depth: it varies depending on the section of river:

All the figures quoted for both the tidal and non-tidal Thames are approx as the riverbed is constantly changing and it does not take into account rainfall and other weather effects or surge tides in the North Sea.

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Question: How wide is the River Thames?

Answer: It varies in width considerably along its length and is about 18 metres (60 feet) wide at Lechlade and about 100 metres (325 feet) wide at Teddington.

The tidal River also varies in width along its length. It is 265 metres (870 feet) wide at London Bridge, 448 metres (1470 feet) at Woolwhich, 732 metres (2400 feet) at Gravesend and about 8 km (5 miles) between Shoeburyness and Sheerness.

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Question: How much water passes over Teddington Weir?

Answer: The freshwater flow over Teddington Weir is normally maintained at about 800 million litres/day (178 million gallons/day) but it can be as low as 200 million litres/day (44 million gallons/day) in times of drought. Conversely, it may exceed 30,000 million litres/day (6600 million gallons/day) during the winter. The mean flow (taken over 25 years) is about 5200 million litres/day (1145 million gallons/day).

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Question: How many boats are there on the River Thames?

Answer: There are no statistics available for the tidal Thames but on the non-tidal River, in 2004, 14057 craft were registered to use the Thames (9049 motor boats, 352 hire boats, 57 passenger steamers, 99 houseboats and 4500 unpowered craft). In addition, there were 2483 boats using the river but were exempt from registration (approved Youth Association, Racing Club and Crown craft) with another 5277 visiting boats excluding the 2917 boats that were issued with 'Open Event' plates.

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Question: Do I need to register or licence my boat to take it on the River Thames?

Answer:You cannot have a boat on the non-tidal River Thames without it first being registered with the Environment Agency (the navigation authority) . This applies to all types of pleasure craft, including motor cruisers, sailing boats, narrow boats and open vessels such as canoes or rowing boats. An annual fee is payable upon registration and covers the period 1 January to 31 December. A licence plate is then issued which must be displayed on the vessel.

Visiting boats also need to be registered to cover the period of the visit.

A boat does not need to be registered nor is a licence required to take a boat on the tidal River Thames.

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Question: Where can I get registration documents to take my boat on the River Thames?

Answer: Registration documents for the non-tidal Thames can be obtained (by post only) from:

Environment Agency
Kings Meadow House
Kings Meadow Road
Reading
RG1 8DQ
Telephone : 0118 953 5650

Boats visiting the Thames also need to be registered and there are three types of registration available.

Option 1 - one day certificate (max 6 per year);
Option 2 - 15 consecutive day certificate (max 2 per year);
Option 3 - 31 consecutive day certificate (max 1 per year);

It is now possible for boaters visiting the Thames to 'mix and match' their visitor registration certificates. You can now choose a combination of the three different registration certificates per year which will allow visitors to travel along the Thames for a total of 67 days by purchasing up to six one-day registrations, two 15-day registrations and one 31-day registration.

Visiting boats entering the Thames from another waterway or launching into the River from one of the many slipways, may obtain registration documents at any of the following locks during published hours of duty.

Any boat that is fully registered with the Environment Agency (EA) for use on the River Thames can have a FREE two week visitors licence for the River Medway and for the EA's Anglian Region's navigations.

From 1 January 2000, owners of private boats based on the Thames can apply for a joint registration and licence (called a 'Gold Licence'), which will allow the boat to be used on the Thames as well as on other waterways under the jurisdiction of the EA or British Waterways in England and Wales.

Special application forms for a Gold Licence are only available from:

British Waterways
Willow Grange
Church Road
Watford
WD1 3QA
Telephone : 01923 201120

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Question: How much will the Annual Registration Fee be on the River Thames?

Answer:The Annual Registration Fee in 2005 for Class N (launches not for let or hire) is £10.54 per square metre of boat per year (Overall length in metres to one decimal point X Beam (width at widest point) in metres to one decimal point X £10.54)

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Question: I am new to boating. Can you give some advice on what type of boat to buy for the River?

Answer: It's quite difficult to give advice about buying a boat as there are so many aspects to consider.

However, here are a few points to ponder:

1. Do you want to sleep on it? If you don't then a day boat (a boat without cabins) is a possibility. If this option is chosen one of the other points to consider is whether you want to moor it on the river or in a marina (with the expense that would be involved) or whether you want to trail it and keep it elsewhere. Most trail boats would have outboard motors.

2. If you do want to sleep on it, you then have to decide for how long. If you only want to use if for the odd night or weekend then a small boat about 20 - 25 feet (6.0 - 7.6 metres) would be OK for a family of four. If you wish to use it for longer periods, for instance a holiday, a slightly longer boat of 25 - 30 feet (7.6 - 9.0 metres) would be better and perhaps should be fitted with a water heater, heater, fridge, cooker, toilet and shower.

3. The other point to consider is the type of fuel to be used, petrol or diesel. A petrol engine boat is cheaper to buy but more expensive to run. Petrol is also difficult to find on the river. The safety aspect of petrol should also be taken into consideration. Diesel boats are more expensive to buy but cheaper to run as red diesel is duty free (at present). Diesel is readily available at a number of marinas along the river and is a much safer fuel.

4. You also need to consider whether or not you intend to cruise outside the confines of the river as it is important to remember that a boat built for the river will not normally be suitable for the sea but, in most cases, a boat built for the sea will be OK for the river provided that the air draught (the height of the boat above water level) is such that the boat will go under the bridges and the draught (the depth of the boat below water level) is not so great that the boat will ground when trying to moor alongside the river bank.

5. If you do intend to extend your cruising to cover coastal and sea areas as well as the river, then you need to consider what type of hull to choose (Displacement, Planing or Semi-displacement). Whatever you ultimately decide upon it will be a compromise: it always is. A displacement boat is fine for the River but can be a little slow at sea. A planing boat is fast and great for the sea but when it comes to river work it can be difficult to keep the speed down, particularly if it has large twin engines, and the lack of a keel can make it more difficult to manoeuvre in confined spaces especially when windy. Consequently a semi-displacement cruiser is a good compromise as it is faster than a displacement boat but not as fast as a planing boat. They generally have good boat handling characteristics and they usually have good accommodation as well as wide decks to make boating on the river easier (you can walk easily to the bow to enable a rope to be thrown over a bollard in a lock).

6. So, what about the engine(s)? A single engine is quite sufficient for inland waterways both in the UK and Europe but a bow thruster is very useful addition as an aid to manoeuvring. Nearly all the boats built on the Continent for inland cruising have single engines and most have bow thrusters. As far as engine size is concerned an engine on a small boat built for the river can be as small as 35hp. On the other hand, for going to sea, a boat fitted with a single 130hp engine is quite capable of crossing the Channel and for coast hopping but we personally feel happier at sea with twin engines. However, although diesel engines are very reliable, it is more often as not a fuel problem that causes an engine to fail. Twin engines therefore only give that extra comfort if you have twin fuel tanks and a separate fuel supply and filters to each engine and the ability to change or turn off a supply from one tank to another. On twin engined petrol boats separate batteries for each engine are also required. Twin engines also make it easier to manoeuvre a boat if you haven't got a bow thruster. The size of engines on twin installations will depend upon the speed you want to achieve when you are at sea. For speeds around 15 knots probably 2 x 130hp would be OK but you would need to talk to the boat builders as each boat is different. It would also be advantageous to have naturally aspirated engines on whatever configuration - much better than turbos for low speeds on the river. In the end the number of engines is a personal choice and very much depends upon your knowledge of engines and your ability and confidence to carry out repairs or change filters etc at sea if the need arose.

7. Fuel consumption will depend upon the size of engine(s) and speed. On our boat, which has twin 100hp engines, it varies between 2.5 to 4 litres per hour on the river to about 15 litres per hour when crossing the channel fully loaded and doing about 10 knots. That is per engine. Fuel prices vary in the UK but on the River Thames it is about 30 pence per litre. (In the UK and Belgium diesel is duty free for private boats but this is not the case in France and the Netherlands where the price is about 0.85 euros per litre). Diesel is readily available at many marinas but petrol is hard to come by - for this reason and the fact that it is not duty free for boats - does not make it an ideal choice for boat engines.

8. Other costs to consider are insurance, marina fees and, if you are on the Thames, a licence. The cost of insurance will vary depending on you cruising area. For unlimited use in UK and Continental waters including Inland Waterways of Europe we pay about £700. This can be reduced considerably if your cruising was limited to the Thames with the occasional trip to sea not exceeding 15 days. The cost of an annual Thames licence in 2005 for Class N (launches not for let or hire) is £10.54 per square metre of boat per year (Overall length in metres to one decimal point X Beam (width at widest point) in metres to one decimal point X £10.00). Marina fees vary from marina to marina but are between £200 and £250 per metre length of boat per year including VAT.

9. Before actually buying a second - hand boat make sure that it has a Boat Safety Certificate, as without one you won't be able to get a licence to use it on the river.

10. We would suggest that you visit a number of brokers at the various marinas on the Thames to have a look at what you can get for your money. You can get a boat from about £3000 upwards. Motor Boats Monthly also has a number of adverts for brokers on the Thames.

11. Where you keep the boat is very much a personal choice. There are many marinas up and down the River and a number of riverside moorings. It depends upon where you live, where you want to cruise and the level of facilities you are looking for as well as the price you are prepared to pay!

This is a brief over view, but if you have any more questions then please e-mail us.

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