Electronic Compasses – which one is right for you?
It’s been a year since the ILCA Rule 22 change came into effect allowing the use of electronic compasses. The Raymarine MicroCompass (more commonly known as the ‘TackTick’) quickly became the default choice amongst most of the top sailors – driven in part by the fact that when the rule change came into effect it was, alongside the Nautalytics simple compass, the only choice. More recently the Velocitek PRISM was released – a state of the art compass – and it is gaining traction against the other two compasses. All three of these compasses are ILCA Rule 22 approved.
How do you decide between these compasses? This article looks at the factors involved, but first why choose an electronic compass? You only have to look at Laser medal race videos to see that the vast majority of the top sailors have moved from analogue to electronic. Electronic compasses are smaller, lighter, but it is the ease of reading that is the main reason – the digital display is much clearer than the graduations on an analogue compass, isn’t subject to the variation dependent upon viewing angle, and is faster to respond to heading change. All these lead to electronic compasses having greater useable accuracy which make it far easier to see heading changes.
So, what are the factors that need to be considered in deciding which electronic compass is right for you?
MODE – The first and maybe the most important factor is whether you want to use your compass in tactical or heading mode. The vast majority of analogue compasses used on the Laser had a tactical scale (normally with a secondary 0-360 scale), which divided up the 360 deg scale into 20 or 24 segments. This in theory, gives you the same or similar number on either upwind tack meaning that it easier to remember – for example 2 on starboard/2 on port (for the Plastimo), or 2/12 (for the Silva/Nexus). The secondary 0-360 scale helped with head to wind and line bias. These analogue compasses assumed an 90 degree angle between tacks. In theory fine, but the tacking angle on the Laser is dependent on the wind strength, is affected by wave skew and any ‘tide wind’ generated by current flow. So your tacking angle may not be 90 degrees and may be also skewed relative to the true wind direction from one tack to the other.
The TackTick is the only one of the three ILCA approved electronic compasses to offer a tactical mode, and the tacking angle can be adjusted on the water to get the same numbers on each tack. However, it still assumes a constant angle from one tack to the other, so if there is skew from one tack to the other the numbers displayed won’t reflect the true wind direction. In tactical mode the sensitivity can be adjusted to 1, 2, 5 or 10 degrees, with most sailors choosing 5 degrees to avoid being distracted by minor shifts.
Some top sailors use the TackTick in tactical mode and others in heading mode. However, I believe that the complexity of using tactical mode simply and effectively, especially when electronic compasses offer greater useable accuracy, has resulted in more sailors moving from tactical mode to heading mode.
Heading mode displays the bearing that the boat is travelling on, so the numbers on one tack are very different from the other and as a result there are two ranges of numbers to remember (or write on the boom)! All three compasses offer heading mode. One potential downside of heading mode on all three compasses is that they display 1 degree heading changes which means that in reality the display is changing a lot. You need to make sure that you are not looking at the compass too much! The PRISM compass does have an adjustable damping rate to help this aspect – the greater the damping value the smoother the heading change will be, as it slows down the response to a change in heading.
TIMER – The rule change also allowed the use of a countdown timer to be integrated with the compass. This is a feature that is included in the TackTick and Nautalytics compass. The timer on the Nautalytics is simple to use, with a sync function that syncs down to the next minute like most sailing watches. However you may find using the timer mode on the TackTick confusing as the sync function works differently (it syncs to the nearest minute, so it may sync up rather than down). Some people use the timer functions on these two compasses but when the timer is running you can’t see heading information unless you manually change modes. When the timer reaches zero the TackTick compass reverts to the tactical or heading mode that you were in. The Nautalytics reverts to its heading mode.
DISPLAY – The size and readability of the display is another important factor. The relatively small display on the TackTick probably reflects the age of the design. The viewing angle is also quite small meaning that if you are either sitting in the cockpit in very light airs and looking down, or doing a head to wind and looking straight at the compass from the middle of the cockpit, you will find it difficult to read. The display on the PRISM is both larger and has a far better viewing angle and a non-reflective coating. The single very large display on the Nautalytics is probably the clearest, but it is a large compass in comparison with the lower profile, sleeker TackTick and PRISM.
If you sail using polarised sunglasses the display on the TackTick is like a lot of LCD’s, unreadable. Only the PRISM and Nautalytics are compatible with polarised glasses.
BATTERIES – All three compasses have inbuilt batteries recharged via solar cells. In the unlikely event that the batteries do wear out, the PRISM and Nautalytics batteries are cost effectively replaceable.
MOUNTING – From a mounting perspective, for the popular TackTick there are a number of mountings available from third party manufacturers such as CarbonParts. For the PRISM mountings are available from CarbonParts and Velocitek. For the Nautalytics the manufacturer offers a mounting. Most sailors choose to mount the compass midway between the block plate and the cleat base, with the control lines running through the mounting so that if it does become dislodged during sailing the compass stays on the boat! If you want to mount it in front of the mast, attach a security line or, if you run your centreboard elastic to the bow eye, pass that through the mount. Most mounts attach using 3M DualLock – best described as a sort of industrial strength Velcro – it really works.
So how do you choose between these three electronic compasses?
About Southeast Sailboats…
Southeast Sailboats is a leading supplier of world class control line systems and electronic compass / mountings for the Laser. We supply all three ILCA Rule 22 compasses and associated mountings and we deliver worldwide https://southeastsailboats.co.uk/compasses/