Garmin question

[MacPE6]

I have a Garmin 3006 with a GLD-20 which came with the boat when I bought it. The question is I was looking at upgrading but after reading many postings I have decided to wait some but is worth it to upgrade to the GSD-22?

I like what I have and am still in the learning curve, not that it every stops, so questions are often.

[wide open]

it is the analog sounder module vs. a digital one...if you are running a nice ducer, like atlease a 600w through hull, I would upgrade. it is a simple upgrade, although you may need a software update.

[yachtjim]

It will be a noticeable improvement. Just about any Garmin ducer is 600W minimum. The transom mount ducers like the P66 have the exact same inards as they thru hulls like the B744 or B60. The thru-hull just work better at higher speeds in most cases.