Design Advantages with the SailTimer Wind Instrument™
Ultrasonic wind sensors are not designed for sailboats because the air slot needs to be horizontal. Ultrasonics have no moving parts, but they do have mechanical problems…
a) The SailTimer Wind Instrument contains an amazingly sensitive digital compass chip, about the size of the head of a pin. The SailTimer Wind Instrument does have a simple, reliable axle design for wind direction, but our digital compass doesn’t have any moving parts. This is a simpler and less expensive design than 4 ultrasonic sensors and the calculations, electronics and compass that go with them.
b) The SailTimer Wind Instrument has patented wind cups that are designed to maintain equal accuracy when sailing along heeled over. But the air can’t flow through the horizontal slot on an ultrasonic device equally well when it is leaning away from the wind. Also, the curved lower edge creates turbulence and affects the wind speed as it passes over the lip, and change the direction of the air passing through the slot. Ironically, that is a mechanical issue with ultrasonic sensors (and a design flaw). In their brochure, you can see that the popular AirMar ultrasonic is not recommended for sailboats, only for “powerboats and commercial vessels”. Other ultrasonic sensors have the same problem.
c) One of the biggest problems for someone needing a masthead anemometer is that their boat is often already in the water. So it is expensive or a big nuisance to have to lower or climb the mast. All ultrasonic sensors have that problem. But part of the patented design for the SailTimer Wind Instrument is that it is the only masthead anemometer that can be raised from deck level, to use it until there is a chance to get at the masthead.
d) An ultrasonic is often sold as a single unit, but could also require an expensive mounting rod to raise it off of the masthead. That may be a substantial extra cost.
e) The SailTimer Wind Instrument provides a visual indicator of wind direction and wind angle. For sailors, looking up to check the wind direction on the arrow is like an automatic reflex, and is very useful. Ultrasonic sensors can’t do that. They don’t provide visual feedback from a real wind direction arrow. An actual customer said it best:
These past 5 days we sailed a little over 110nm… what became very obvious was the awesome design… Since I have both the SailTimer and a standard Windex on top of the mast you could clearly see how the SailTimer was steady and not whipping about with every wave and motion of the boat. After hours of sailing I started ignoring the Windex and only observing the SailTimer as a reference for wind direction… The SailTimer was providing far more accurate AWA on a visual basis than the Windex.
So the design of the SailTimer Wind Instrument has fundamental advantages (and a lower price).