I have both a speed puck and a tacktick compass. The speedpuck reads out either sog. Speed over ground, or cog, course over ground. But not both at the same time. These are derived by using the GPS position sensor inside the unit. What they call heading should be called course over ground. It does not not tell you magnetic heading and cannot be programmed to give you magnetic heading as it has no compass sensor in it. So it cannot tell you which way the bow is pointing, it only tells you which way the speed puck is moving over the ground. It cannot adjust for side slip of the boat in the water , or currents in the water. It only gives gives usable info if the boat is moving at a good pace and there are no currents and you sailing with very little leeway. It has been useful to bring boat to a dead stop and then read it over a few minutes and you can figure which way the current flows and how fast. But it needs to be very little wind and pretty strong current to get usable numbers on currents. Yet when the boat is moving it does help you know numbers on a comparative basis. If wind and current are consistent and your heading changes say 15 degrees , you most likely changed your course over ground by the same amount. This makes it a good racing tool.
What I do is use the tacktick for magnetic heading and the speed puck for speed over ground. If there is very little current this seems to work fine as long as boat speed is over 1 knot and we keep the boat flat so leeway is not big and is consistent tack to tack.
What I do not remember is if the speed puck can have the local mganetic variation programmed into it.
Jim Knape
Ensign 1576
On Friday, June 14, 2019 Ensign Sailing Forum <ensignsailing@ensignclass.com> wrote:I have two Velocitek Speedpucks which, I believe, are giving me "true" headings and not "magnetic" headings. I have Windows 7 and apparently cannot go to the Velocitek Control Center to change settings. Any suggestions? I am located in the Boston area.
Jody Graul (Plebe Year 1217 and Bonanza 385)