The modern compass is divided into 360 degrees. Typically, we only use the cardinal and inter-cardinal points: in the first case, North, East, South, and West; in the second, Northeast, Southeast, Southwest, and Northwest. Most of us are accustomed to thinking of ninety-degree angles, and of expressing opposites as ‘180 degrees’ apart, but the compass plays little role in many modern lives, beyond the knowledge that the sun rises roughly in the east and sets in the west. Mariners, however, think of everything in terms of direction – the wind, the current, the position of the sun or a star, their own course, and where the land is – or might be. Spatial orientation is key to a conception of order out of chaos on board ship.

Mariners in Sultana's time used the thirty-two-point compass, illustrated below (see Figure 32). One point translates to 11.25 degrees, but that is not how they thought of it. The demands, and limitations, of practical navigation under sail did not require the precision offered by the 360-degree compass. This older compass might at first seem challenging to comprehend, but the notation is actually straightforward.

The eight ‘half winds’ bisect the four inter-cardinal points. The key to remembering them is that the first direction is modified by the second (as with the ‘quarter winds’ – see below). So, ‘ENE’ (East-Northeast), halfway between Northeast and East, is ‘Northeast of East.’ ‘SSW’ – South-Southwest – is halfway between South and Southwest – ‘Southwest of South.’

The ‘quarter winds,’ the finest divisions in the thirty-two-point compass, bisect the ‘half winds.’ As with the ‘half winds,’ the first direction given in a ‘quarter wind’ is the primary direction, and the second direction is an adjustment to that. So, for example, ‘NEbE’ (Northeast by East) may be thought of as ‘Northeast adjusted to the East,’ or, ‘a little bit East of Northeast.’ ‘SWbS’ means ‘Southwest by South,’ and that means ‘a little bit South of Southwest.’ Quarter winds are identified by the ‘by’ between the two directions, usually written as either ‘b’ or ‘x.’

The compass used by David Bruce and John Inglis in Sultana's logs is actually a further division of this compass into 128 points, but the thirty-two-point compass is more than adequate for understanding anything presented in this book, or likely to be encountered in other maritime histories of the period.