question about sonar/gps unit and navionics cards

[dremarquis]

Hi all,

i was trolling the North end of canandaigua, which is new to me. riggers down about 80 and then i'm into a hump that's 20 feet down. Major &^$&*%$!!!! hassle. I decided i really want a sonar unit that has both the capacity to mark waypoints and shows topo maps of area lakes.

i'm considering the Humminbird® 581 i Combo Sonar/GPS (on sale at cabelas for $280).

I have heard mixed reviews about the Navionics® HotMaps™ Premium SD cards.

I'm curious if any of you have that card, and if so, how detailed are the contours of fingerlakes? Also, does it have many of the ADK lakes included? I presume the Lake Erie and Ontario contours are accurate and detailed?

any input on the Humminbird 581i would also be appreciated.

thanks a bunch,

andre

[Frisco]

I tried a friends card on my Lowrance 5300 used it on Oneida and couldn't wait to get home to order one from Cabelas. I'll use it Sunday on Cayuga will let you know how it worked on deeper water, the performance on Oneida was top notch it marked the shoals perfectly.

[Jonboy Walton]

Just my two cents about gps, maps and sonar....trust the sonar, use the maps as a guide. There is built in error for non military gps and consequently you are not where it says. You will be close but I have seen the error be as much as 120 feet or more one way or the other. navionics is pretty good and will help you ID structure and underwater features which is really what you need. Spend the money on the best sonar unit your money will buy and build on it. It took me over a year but I have a Lowrance HDS 10 and side scan sonar...worth every penny. It has made me a much better fisherman all the way around. I am running a navionics platinum chip and use it to "preview" where I want to fish. Just my program, hope it helps.

[quality time]

The map is near spot on for Cayuga, Found some places on Senaca that it was off some. Not sure on other lakes. Error is less than 50' on gps these days. That will get you pretty close. We have gone down canals in pitch black following tracks from daytime trips and it got us there safe. Nothing is perfect but we find this to be a great tool. Wes

[luv2fish]

My bet is that you were on the north east side near the dragon wall. There is a crazy contour there that we call the stove pipe. Goes almost straight up all the way around with a total distance of maybe 50 feet wide on top. Drops right off all the way around. There are also two hills running north-south up there that you need to watch for. I have a humminbird 800 series which is the newer version of the 917C and I like it. Have used the navionics units on some other boats and they seem to be pretty good. That north end is really tricky, I've lost a spoon or two around there! As a rule of thumb I don't go much farther north than the water pump house, that should help you a little till you learn the lay of the land below the water. Good luck!

[ Post made via iPhone ]

[dremarquis]

thanks very much for your input!

andre

[NitroMusky]

There is built in error for non military gps and consequently you are not where it says. You will be close but I have seen the error be as much as 120 feet or more one way or the other.

The use of intentional error was discontinued over a decade ago (which was one of the factors leading to LORAN system being dismantled).

Error is generally no more than 10 ft on modern units (and most times even less). That small remaining error is due to signal degredation and atmospheric issues etc. If its more than that, chances are the WAAS error correction may be turned off or you haven't acquired enough satellites yet.

With the HD maps, navionics are quite accurate. The non-HD are just govt or DEC maps overlaid and tend to be off in both contour and their placement on the map (sometimes shows me navigating up on shoreline ). Wish they were all HD...

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[pschauf]

I have a lowrance 10" screen maybe 5 year old model and the sonar is great - surface temp sucks - gps map of land great - contours of seneca lake bottom is terrible and the pre-loaded lake contours can be off as much as 100 feet - someone generated the lake contours in an office 1000 miles from the lake - no idea of the true contour of the lake - maybe there is a chip or card that is more on the money but out of the box with pre-load program, I'm disappointed.

[NitroMusky]

You want to add the navionics map chips. Seneca lake (along with a few of the other larger lakes locally) were surveyed (foot by foot) by navionics, so the depth and coordinates are basically spot on.

[ Post made via BlackBerry ]

[pschauf]

thanks

[ManOverboard]

how detailed are the contours of fingerlakes?

Here's a screen shot of N end of Canandiagua from Navionics. I know some are yet to be mapped (Keuka for example). If there are any in particular you want to know about post back here and I'll see what they have.

[NitroMusky]

It gets a heck of lot more detailed than that...if you zoom in on the fishfinder you can get it to show every one ft contour break on cndga, since its mapped in HD

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[ManOverboard]

It gets a heck of lot more detailed than that...if you zoom in on the fishfinder you can get it to show every one ft contour break on cndga, since its mapped in HD

[ Post made via BlackBerry ]

Absolutely. If I zoomed in much more you would loose perspective on where you were. Here's a shot with more detail:

[NitroMusky]

There ya go

[ Post made via BlackBerry ]

[pschauf]

Where can you get the best card for seneca lake locally???

And the big O too ?

[ManOverboard]

Where can you get the best card for seneca lake locally???

And the big O too ?

Morgan Marine in Penn Yan is listed as a dealer for Navionics. Not sure if they stock the chips or if you have to order.