Tuesday, 7 February 2012

On Manoeuvres (7)

This is one of an occasional series of tips about manoeuvring a narrow-boat on the canals and rivers. There may be other ways to achieve the same result. However, the method has been devised or adapted by me using trial and error. (Trial and Error are two of my regular boating companions) Our boat is 50 feet long and has a keel depth of twenty five inches and weighs in at a tad over eighteen tons. The techniques described are intended to help new comers to boating.

Observation and the understanding what you are observing, is paramount to handling the boat. There are many visible clues that you can learn to read which will make your journey much easier, safer  and interesting.

The wind for instance can be your friend or your enemy when moving your boat. Narrow boats can be greatly affected by the wind due to being flat bottomed and presenting a large side area to act like a sail. With a little thought and pre-planning the wind can sometimes be utilised to provide some assistance when manoeuvring a boat. But which way is the wind blowing. Ripples on the surface of the water can give a good indication of the wind direction. A small pennant or piece of ribbon mounted on your boat can give an indication of the wind direction when stood or moving very slowly. Waves or ripples on the surface of the water are a good indication of the winds strength and give an indication of whether to continue moving or if it is time to moor up until the weather improves.

Water movement can be difficult to read. The direction of water flow can only be read if your boat is stood still in the water. Your boat moving through shallow water will create erroneous indications. Surface ripples can give the impression of movement in the water when there is no movement at all. Small objects floating in the water can be moved by the slightest of breezes.

The best way to see if there is any current and which way the current is flowing is to look into the water margin and see in which direction the water weed is laying and how much it is waving in the current. When observations of water movement are made near locks, water movement can be an indication of a lock being filled or drained. When water movement changes from one direction to another and then back again. That is a good indication of other moving boats drawing near.

Generally, where there are no waterside plants this is an indication that the water is too deep at the edge to support them or that water movement is swift enough to scour the plants loose. Overhanging trees can be a very nice sight to behold. They can also be a pain due to the amount of debris they collect especially from your boat roof. Every boater has lost equipment off the roof with items being swept off by low tree branches. Your boat paintwork will always come off second best to tree branches. Aim to avoid passing under tree branches hanging close to the water surface.

The bottom contour of a canal is dish shaped, However mud can build up in places where there is little boat movement or no dredging done. When a river turns round a bend the inside or tight part of the bend is where the water moves slowest. Where water moves slow any material in suspension will be dropped to the bottom. Making the river or canal shallower at that point. The outside of the bend is where the water travels fastest and this keeps material in suspension. Generally the water is deeper at this point. It is best to stick towards the middle of the canal or river as this is where the deeper water is generally located. Some rivers such as the tidal Trent have recognised charts that can be used to indicate where the deep water channel is located.

Generally canals have little flow of water. However when in close proximity to a weir the speed of water can prove to be quite an obstacle to overcome.  Many locks are placed close to weirs on river sections which are used maintain water levels. The movement of water over a weir can cause difficulty in manoeuvring when entering or leaving a lock. Watch out for bywashes when approaching locks. Many locks have a bywash, and water flowing over a bywash can make it difficult to enter or leave a lock.


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