Humminbird GPS speed accuracy?

Does anybody have any input on how accurate the internal GPS speed is at very low speeds on the Humminbird units? I've heard they are not very accurate unless going at least 2 mph? If not very accurate it would defeat the purpose of buying a new unit for that purpose for the front of my boat. I would use to troll and we all know how just .2mph in speed can make a difference in catching fish. Would I be better off to just use a handheld unit to determine my speed over depending on a fishfinder? thanks

I use the Navionics phone app which shows your speed as well as my Humminbird 899. I have been able to match speeds on both. Try testing with a GPS app to see how much off it is.

I have a humminbird 859 and a I pilot both read the same on mph. I have checked with a hand held gps and both are correct. I troll at speeds from .3 to .7 all the time.

I have 998 hs si and with the regular external puck the speed isn't accurate at all, it jumps around everywhere. I also have an HDS 8 with internal antenna and it stays right on. My buddy has the 899 and his speed jumps around like mine. While his old gen 1 hds 5 is right on. So in my opinion the HDS2 units is what I would get for speed accuracy.

Sounds like a crap shoot..... I have a 788ci(internal antenna) that goes like a mexican jumping bean! 998 with external and I pilot are both stable and in agreement.

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Originally Posted by cache22

Sounds like a crap shoot..... I have a 788ci(internal antenna) that goes like a mexican jumping bean! 998 with external and I pilot are both stable and in agreement.

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The internal antenna probably has little to do with it. 788 has a much smaller processor. Share the external with the 998 or wire the external directly to the 788. I would think you will see the same bean jumping. 788 have a clear view of the sky?

Most of the inaccurate readings are mounting issues or interference from what I have found. I have never had a Humminbird have a problem with speeds. I change units every two years. I do get the donut though at times.

A hummingbird with the optional better external puck would probably be your best bet...To trade pucks you would have to buy one of the still new 898, 858, 998,958,etc.... I think they still do it, e-mail or call them to find out and which units qualify..... it is $50 extra to trade pucks with hummingbird after you buy your unit. It Is also a heading sensor puck so you never get a donut it will always show the direction your boat is pointing....... Just don't take the original pucks out of the original packaging and they will trade with you, like I said for $50. If you buy the new units the heading sensor puck outright it is $200. This, I'm sure would work for accurate speed if you want a hummingbird unit. Or you could buy a used unit and put the heading sensor puck on it. Like I said originally though I would just buy a used Hds5 gen2, or hds7gen2, or 8gen2 and you will get accuracy with the internal puck.

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Originally Posted by crappielimits

Most of the inaccurate readings are mounting issues or interference from what I have found. I have never had a Humminbird have a problem with speeds. I change units every two years. I do get the donut though at times.

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Do you get a "donut" with an HS puck?

You certainly will with a standard puck.

Maybe the more high end units are better but, I have a 597ci hd and it sucks in every aspect. The speed is nowhere near accurate at very slow speeds. It jumps all over the place and there is no way to know what your true speed is. Also at very slow speeds the GPS will show the boat 150 to 200 feet off coarse up on the bank at times. Like I said maybe the higher units are better opt for one of those if you can swing it. just my :twocents.