Search patterns for lost crew members 1.
On any RYA practical course, a considerable amount of time is spent practising the manoeuvres required to return to a person who has fallen overboard.
Fortunately this is something most skippers will never have to face for real. It is still worth practising, in case it does ever happen but also because is sharpens the skills of boat handling and crew control.
What is not normally practised is what to do if you lose sight of the casualty and have to start to search for them. This is a skill that should be practised occasionally because you would not want to trying to work the best approach in a real emergency.
On some high level courses I include the following 2 exercises, and even very experienced yachtsmen will struggle with the concepts the first time.
If you lose sight of someone but have a GPS position from the use of the MOB button, you should return to that point. If there is not much tide they should still be near by. If they can not be seen, the best approach may be to start an expanding square search pattern as below.
The length of the first leg should be about the easy range of visibility, 0.1M by the log should be about right.
Each distance should be run twice with a right angle turn in between, then the next leg should have 0.1M added to it.
Slowly, you will cover the entire area very thoroughly.
One technique that makes this easier is for the first course to be an easy one to remember, 000/090/270 degrees are good choices. Calculating the following courses is then much simpler.
It is also easier if the person running the navigation does nothing else, they should be plotting the movements and recording the bearings and distances run. This takes a great deal of concentration.
Obviously, in an area of strong tidal streams, the exercise should be started from a point that allows for the tidal drift from the GPS position. Once the search has started, the boat and the person should move together.
All spare crew should be on deck, as high up as possible.
When practising this approach, I recommend searching for a small object. A green apple works very well!
This technique will work, but it requires practice and takes a long time.
Sailtrain.co.uk is free to use, but if you feel you would like to contribute to the running and development costs you can donate via Paypal: