The tidal Thames is a fantastic place to cruise -- seeing London from the river in your own boat is a most satisfying experience. The Tideway can, and should, be used by all types and sizes of boat, but owners must be aware of the challenges and hazards they may face. The tide can run very fast, and there is still a considerable amount of commercial traffic, mostly now in the form of trip-boats, some of which travel at high speeds.
Tides and other vessels, as much as the wind, can combine to create an unpleasantly lumpy surface. As a result, piers and pontoons are often lively. Despite the best efforts of the PLA to clean up the river, you still need to keep a very sharp lookout for flotsam and jetsam, especially on spring tides.
Commercial traffic
It is the normal practice to keep clear of all commercial traffic, as many of these types of craft have difficulty in manoeuvering and stopping. Barges towed by tugs are particularly difficult to manoeuver through bridges, and many of the bigger trip boats can only alter course slowly. A careful lookout should be maintained astern as well as ahead, and appropriate avoiding action should always be taken in plenty of time.
Large vessels
Remember that large vessels under way are frequently confined to the deep water part of the channel. They cannot take quick avoiding action, and in narrow channels may not be able to take any avoiding action at all. If you find yourself in close proximity to a large vessel, a strong sense of self preservation is recommended. Get clear as quickly as possible.
Right of way
Any boat approaching a bridge or bend in the river when going against the tide should give way to a boat approaching with the tide. Oarsmen never give way to anyone - it's just one of those things!
Overtaking
If you overtake another boat, you should keep well clear of the slower boat. If you are being overtaken, officially you should maintain your speed - you may decide to slow down to let the other boat past, but don't speed up. Sound signals should be made in good time as appropriate.
Crossing the river
When it becomes necessary to cross the river, this should be done as swiftly as possible, with a good lookout for other traffic. Any attempt to cross ahead of oncoming traffic could prove very hazardous. A vessel crossing the river has no right of way over other traffic.
Keep to the right
When proceeding up or down the river, all power driven vessels should, while it is safe and practicable, keep to the starboard (right hand) side of mid-channel.
Speed
Above Wandsworth there is a speed limit of 8 knots (9 mph) through the water. Below Wandsworth there is no specific limit, but speed should be adjusted to ensure that there is no damage caused by excessive wake. For most pleasure craft this is not likely to be a major problem, but bear in mind that there is a fine of up to £1000 available!
Bridges
Unobstructed arches for navigation are denoted by two orange/red lights placed horizontally at the head of the open span. Other spans may also be clear for small craft, but if in doubt it's probably best to stick to the marked spans.
A triangle of red disks or three red lights hanging apex downwards from the arch of a bridge indicates that the arch is closed to navigation.
If the span of a bridge is restricted in headroom, due to maintenance or repair work, a bale of straw will be hanging from the scaffolding. Honestly, they really do use bales of straw - they have to, it's the law. I love it! At night the bale of straw will be replaced by a white light.
If you see a flashing white light in the centre arch of a bridge, day or night, this means that a large vessel is approaching - normally a coaster or a train of barges. It may be coming in either direction, so keep a good lookout.
Regulations
Bye laws of particular relevance to leisure boaters are:
The name of any vessel must be clearly displayed.
Any vessel 12 metres (approx 40 ft) or more in length suffering damage must inform the PLA Harbour Master, must not proceed above Lower Hope Point or move, if above Lower Hope Point, without the Harbour Master's permission. Lower Hope Point is near Tilbury, roughly 30 miles downriver from London Bridge - you are likely to be above it!
A competent person must be in charge of a vessel at all times
All vessels must comply with the appropriate navigation light requirements. Don't think you can get away without lights if it's dark - it's not unknown further upriver or on the canals, but is absolutely not recommended here!
All vessels shall be securely moored, unless underway or at anchor.
All vessels shall be equipped with one or more anchors unless under 7 metres (approx 23 ft) in length or a rowing boat. An anchor really should be considered essential equipment - not because the rules say so, but simply common sense. If you have an engine failure or fouled prop, when the tide is really running you will definitely want something to stop you careering along with the tide.
Any river user must not navigate while under the influence of drink or drugs. PLA Harbour Service launches are equipped with standard breathalyser equipment, and Masters are instructed to administer this test as appropriate.
