A Ansar 1 compass is here shown viewed from the windward starboard side and some 20 degrees from the center line of the boat.
The compass has two transparent cupolas facing sideways.
Embedded Files
Ansar's compasses
Ansar's compasses
Ansar 1 compass shows same large digit on both tacks and is adjustable for tacking angle
Ansar 1 compass shows same large digit on both tacks and is adjustable for tacking angle
Videos
Read the compass http://www.youtube.com/watch?v=ofmWL95hHjM
Adjust for angel between tacks http://www.youtube.com/watch?v=S-LPwEySiBg
The compass manufacturers Silva, Ritchie and Plastimo have copied the dial of Ansar 1. These compasses are a not very useful as they don't have the very important feature of adjustment for tacking angle, which is different for different types of boat and the varies with wind speed. There readings therefore hav a fault of some 0 to 10 degress which is far too much when you want to tack on windshift in the order of 10 degrees.
This compass helps the racing sailor by showing the same large digit on opposite tacks. It is an alternative to the Ansar 2 or 4 compasses in boats: where no one can always reach the compass to adjust the markers while sailing, for instance in a trapeze dinghy, or in a boat (dinghy), where it is felt that reaching in, from the hanging out position, would result in a too large loss of way.
In preparation of tacking on oscillating wind shifts you sail to windward and note the indication of the compass for best lift on both tacks, let's say 3 on starboard tack and 4 on port tack.
Then sailing on starboard tack with compass indicating 3 you sail in best lift, 3.5: in zero lift and 4: worst header.
On port tack 4: best lift, 3.5: zero lift and 3: worst header.
As you see here when sailing with a compass indicating numbers on one tack numbers decrease when reading improves. A complication you don't have with Ansar 2 and 4 compasses.
The pictures shows the most sold model of this compass. The view is from behind and the starboard windward side, one cupola faces starboard and one port. It has one lubber line for each tack, some 45 degrees from the center line. It is the windward lubber line which is used.
The compass is adjustable for different tacking angles by turning the compass housing in its fitting. This changes the distance between the slightly inclined lubber lines.
The compass manufacturers Silva, Ritchie and Plastimo have copied this type of dial. These compasses are a not very useful as they can not be adjusted for tacking angle, which means it shows the same figure on opposite tacks only at one specific angle between tack.
If you don't compensate for this there will sometimes be an error of up to 10 degrees - far too much as you usually are looking for shifts down to some 5 degrees.
My concept can also be applied to compasses with other orientations of the cupola: backwards slanted. For these orientations Silva Compasses with letters B or NB in the model number are modified.
"It helped me to gain at least three or four places in each major regatta",
"It helped me to gain at least three or four places in each major regatta",
writes Ed Baird, then a star in the Laser dinghy, in his book on Laser sailing, about the Ansar 1 compass.
The world's fastest skate sail, 120 km/h (75 MPH) is another of my top performance designs.
Copyright © 1996-2000 Anders Ansar. Permission is granted for reproduction provided that the whole document remains intact.
Modified August 2011
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