Tidal flows off Lowestoft
Tips from Bryan & Jenny Riley on how to make the most of Lowestoft’s tides.
The tides off Lowestoft have earned an unjustified reputation for adversely effecting championship racing. We at Lowestoft would argue that racing in a tide adds another dimension to the competition. The objective of this article is to give all competitors sufficient information on the tides to enable you to use them to your best advantage. On a warm day in the summer the Suffolk coast enjoys strong sea breezes, force 4/5 from the south with a swell of 4/5 feet, perfect yachting. Whilst we cannot guarantee the weather, we can explain the tides, which really are nothing like as complicated as in the Solent, the UK’s premier yachting venue.
In the deep water shipping lanes outside the sandbanks, to the south of the harbour, the peak flow can approach 3.0 knots at spring tides. For this reason championships are sailed closer inshore, on what is known locally as the Lowestoft shelf, where the depth of water varies between 12 and 35ft.
Looking at the chart showing the approaches to Lowestoft harbour, you will see that our sailing area is approximately one mile south of the harbour entrance. From the shore, the beach shelves steeply into 20+ feet of water to a maximum of 35 feet, before reducing to 12 to 15 feet approximately three-quarters of a mile off shore. This continues for a third of a mile out to sea, before reaching the shipping lane where the depth increases to 60 feet.
The tide runs south on the flood and north on the ebb, with the direction changing approximately one and a half hours after high or low water. The only complication is that it changes inshore first, which means that as the tide changes it may pay to go either out to sea or inshore on a beat, to make the best from the tide. The key is to recognise when the tide is slowing prior to a change of direction. This can be judged on the reaches by taking a transit off a racing mark and a building on the shore, using this to judge the amount you are sailing above or below the lay line, to compensate for the tide.
Alternatively it is relatively easy to judge the rate of flow as you approach the racing marks, especially as all the marks are fitted with a small, handled mooring buoy, which is attached directly to the base of the marks to enable the club rescue boats to pick them up. These secondary marks always float downstream of the marks themselves, indicating the direction of the tidal stream. It pays to observe these secondary buoys at every mark rounding, thus continuously updating your knowledge of the tide.
The last variable is the depth of water itself. If you are beating in a river against a foul tide, it pays to short tack in shallow water up the inside of the bends. In the same way, off Lowestoft it can pay to sail in the shallow water further out to sea (12 to 15 ft) on the sandbank, compared to 20 to 35 ft in the channel further inshore.
The chart shows the location of the bank, and the shallow water can be identified by the different wave pattern, the waves being shorter and steeper compared to the remainder of the course. Another tip for locating the bank is to take a transit of the pier heads at the harbour entrance and Lowestoft’s only block of high rise flats to the north of the entrance. Drawing a line through these clearly visible landmarks to the sailing area, the line passes over the sandbank. This transit can be used whilst sailing to judge your position relative to the shallow water. These are the techniques we use whilst club racing with only 4/5 boats sailing. However for the championships you will be sailing approximately one mile further south where the influence of the bank is much less because the seabed is “flatter”. In a large racing fleet, it is best to observe the progress of the other competitors and to sail in the area where they are doing best.
Our last tip is that it rarely pays to “groyne hop”, to cheat the tide. There are a number of reasons for this. The beach shelves very steeply and you have to be practically ashore to find shallow water. We have a local rule that you should not sail inside the projection of the groynes themselves. We must also give swimmers a wide berth and finally the wind speed is usually reduced due to the interference of the buildings on the sea front.
View high and low water times & heights for Lowestoft here