SailSteer with Mark Chisnell

Mark Chisnell takes a closer look at the SailSteer display - only available on B&G chartplotters and instruments. 

SailSteer

The Sail Steer app brings together a lot of useful information in one simple screen. It will be useful both to navigators who want to monitor the boat’s sailing angles and progress against a waypoint or mark, and to helmsmen sailing shorthanded.

What’s what with SailSteer

Let’s go through it; the numbers down the left-hand side are all configurable by the user, in this case they are (from the top); boat speed in knots (WATER); True Wind Angle (TWA); Apparent Wind Angle (AWA); True Wind Speed (TWS) and True Wind Direction (TWD).

 The numbers on the right-hand side (from the top) indicate: Magnetic or True reference beside the time on port (P) and starboard (S) tacks to the waypoint; total sailing time (TTW-S) to the waypoint on both tacks; total sailing distance (DTW-S) to the waypoint on both tacks; the waypoint bearing (WPT BRG); and the depth.

 In the middle we have the cool stuff. The image always shows the outline of the boat sailing towards the top of the screen. So when looking forward at the display, a glance up towards the bow and the horizon has the virtual boat in the same orientation as the real one.

 A compass rose in white and black spins around the outline of the boat to show the heading – the actual heading is the highlighted number in black and white, in this case 271 degrees. The little orange egg timer is the Course Over the Ground (COG). And the tide is shown by the blue arrow and number in the middle of the screen; flowing right to left at 1.3 knots.

 The AWA is shown by the ‘A’ in the blue arrow, and the TWA is shown by the ‘T’ in the green arrow (it’s green when sailing on the target true wind angle upwind or downwind, but goes to blue if the boat is off the target by 10 degrees or more, and when reaching). In this example we can see both near to 310 degrees on the compass rose.

 The red and green sectors show the laylines and their limits in the pattern of the wind shifts, with the green and red dashed lines showing the target TWA (laylines) for each tack in the TWD at that moment.

 And finally, the yellow dot at about 340 degrees on the compass rose is the waypoint bearing.

Upwind on Starboard

So what useful information can be gleaned from a quick glance at this Sail Steer panel – apart from the fact that we’re going upwind on starboard, which should be obvious onboard…

 The boat is going right to left over the ground because the COG egg timer is to the left of the bow. This makes sense because the tidal arrow also shows the tide flowing right to left at 1.3 knots.

 The boat is a little high and too close to the wind, because the bow is to the right of the target wind angle line (the dashed green line).

 We can’t lay the mark on port in any likely wind shift, because the yellow dot is completely outside the red sector.

Upwind on port

Now, let’s tack over and see how we look – what can we tell from this Sail Steer panel?

 The boat is going left to right over the ground because the COG egg timer is to the right of the bow. This makes sense because the blue tidal arrow also shows the tide flowing left to right at 1.1 knots.

 The boat is again a little high and too close to the wind, because the bow is to the left of the target wind angle line (the dashed red line).

 We still can’t lay the mark on port in any likely wind shift, because the yellow dot is completely outside the red sector, and to the left of the bow. If I was the navigator on this boat, I’d tell the helm to stop pinching, forget the mark and sail the target numbers… politely, of course.

Downwind on port

So the boat has got around the windward mark and is on the next leg going downwind on port gybe – what can we tell from this Sail Steer panel?

 The boat is going left to right over the ground because the COG egg timer is to the right of the bow. Again, this is correct because the blue tidal arrow also shows the tide flowing left to right at 0.9 knots.

 The boat is still a little high and too close to the wind, because the bow is to the left of the target wind angle line (the dashed red line).

 We can lay the mark on starboard in any likely wind shift, because the yellow dot has passed through the green sector and is now upwind of it. If I was the navigator on this boat, I’d tell the helm to stop luffing, and gybe the boat for the mark!

Downwind on starboard

The helm has done what they were asked (for once) – so what can we tell from this Sail Steer panel now we are going downwind on starboard gybe?

 The boat is going very slightly right to left over the ground because the COG egg timer is to the left of the bow. This makes sense because the blue tidal arrow also shows the tide flowing slightly right to left at 0.7 knots.

 The boat is still a little high and too close to the wind, because the bow is to the right of the target wind angle line (the dashed green line).

 This is not a bad thing though, because the boat is laying the mark – the bow, the COG egg timer and the yellow dot are all just about aligned. We’re on the layline, and the mark is just 4mins and 21secs away – nice work, time to start thinking about the set-up for the headsail…

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