Speed accuracy with Helix?

[FurFlyin]

How accurate is the GPS speed indicated on my Helix 9 Mega?

On the low end.... While trolling? According to my depth finder, the slowest that I can troll with the "big" motor is 3.2 mph. With my dinky trolling motor, in a protected cove out of yesterdays wind I could troll 2.2 mph with my TM. Is the speed on the screen accurate?

[dbowling]

With my 2 stroke 50 hp Merc that's about what mine reads if I go any slower engine wants to load up and bog down.Ive heard 4 strokes can go really slow.

[CrappiePappy]

GPS is pretty accurate on speed ... from what I can tell. I don't really think a few tenths of a mile per hour, one way or the other, is significant enough to be concerned with, since you don't keep the exact speed the entire time (due to wind, waves, or course direction changes).

[FurFlyin]

Thanks for the replies. My week isn't working out like I had planned and that's about normal. My motor took a case of the sputters yesterday and had to take it to my boat mechanic late yesterday. He rebuilt the fuel pump, replaced the lines, filter, cleaned the carb etc.... Then this morning my son woke up with a stomach virus so we didn't go. He's got one more day out of school tomorrow and I'm praying that he's over this virus by then. I sure enjoy spending time with him.

[Spaceman]

Good signal with GPS = very accurate speed.
Spaceman

[cevans]

I run 3 depth finders and they all read within a tenth of a mph of each other if not the same thing. I have even checked my speed with a hand held Delorme PN-60 gps and they read spot on. Where the guys are using the gps puck style add on is for exactness little better maybe for waypoint marking. However, I don’t have a problem in locating my waypoints with the lowrance and hummingbirds that I use.

[skunked again]

I'll let you know if / when i get one!
I've checked my Navionics app on my phone, and some other apps with speed, against our vehicles. Luckily enough, drove past a portable radar unit, the phone matched the portable unit.
I always thought my vehicle speedometer was off, doing the above confirmed that.
I would trust something with gps. As someone said, good gps signal= very accurate speed.