When it was being used, the compass would be held in a wooden stand
called a binnacle. This would probably have been on the aftercastle
deck.
No iron was used in the construction of either the compass or the
binnacle. This is because iron affects the accuracy of compasses.
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Now
you know how a compass works, let's look at one of those from the Mary
Rose in detail.
1
For protection the compass was housed in a wooden box .
It had a sliding wooden lid which we've taken off so you can see inside.
2 The compass bowl is also made
of wood, it had a glass top stuck to it. This protected the compass
card and the needle. The card has rotted away.
3 The
compass needle swung on this brass spike.
4 We
think this iron stain on the bottom of the bowl is all that is left
of the needle
5 The
compass bowl was held inside the box on two brass gimbals. These let
the compass bowl swing in any direction, so it would stay level when
the ship was rolling in the waves.
   
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