Wednesday 12 February 2014

Boat Stuff (2)

There are a very large number of books that have been written about all aspects of boats on the inland waterways. The thing that started me creating a list of hints and tips about narrowboats was that every few days I seem to learn something new.

In Boat Stuff  (1) we looked at establishing how low in the water the bottom or keel of your boat is. Placing a mark on the boat shaft equal to the draft of the lowest point.

We all know that operating a lock is something that needs a great deal of care. You can't allow yourself to lose your concentration even for a moment. It is important to understand how locks work. It's also important to have a ready plan of action in place if for any reason something does go wrong.

There are occasions when the water level between locks can be low. Low water levels can be caused by leakage in lock gates. As gates get older, wear and tear will cause them to leak water. Eventually the lock gates will be replaced. However, leakage through lock gates can create additional problems that you need to be aware of.

Typically when going up in a lock we have to be aware that the front or back of a boat can snag on worn or damaged gates. We need to be aware that water leaking through a lock gate can cause flooding on the front deck.
Typically when going down in a lock. The cill presents the biggest danger. Its possible for the skeg and or rudder to become snagged on the cill. As the water level continues to fall the front of bow of the boat can be forced below the water surface. This will flood the boat in a few seconds. 

There is a third problem that can occur when going up hill in a lock.  If there are two locks close enough together. Then leakage through a lock can cause the water level in the pound to fall. Then the clearance over the lock cill will be reduced. There is a genuine risk of grounding your boat on the lock cill. Then if the water level continues to fall in the lock the boat is at risk of sinking by the stern.  Measuring the depth of water over the cill from the bow of the boat can help to overcome the problem. (You will have worked out the draft of your boat from boat stuff  number one. ) Measure the depth of water with your boat shaft. If the water is below the mark on the boat shaft. Its not safe to continue.

If you find yourself in this dangerous predicament. You will need to flush water down from the lock above. This will bring up the level of water in the lock and pound above. When the boat floats move backwards into the lock. Don't waste valuable time pushing and pulling the boat. Go immediatly to the lock above and flush some water down.

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