Lots of great advice so far.
One little facet I might mention is establishing a Priority of the sailing info that you need
vs. what you might want.
Around the NW, the main thing everyone needs is a reliable depth readout. With that and a paper chart and your everyday ability to take a bearing, you can be fairly sure of where you are. And since running aground is the major cause of recreational boaters' heartburn and bleeding from the wallet, a good DS is always the first thing we need.
Next is the fun stuff, like speed and wind data. The addition of wind data is wonderful as eye candy, but the speed stuff adds to your navigation arsenal. (Yeah, I know... the handheld GPS will give you SOG info, but that's still not boat speed...)
The instrument makers know this, and commonly bundle their data packages into a speed/depth combo that nowadays can use a single transducer, and for more money, will sell you a depth/speed/wind package at a discount.
I bought the Raymarine ST60 package in '02, and it's been reliable & trouble free so far. (If I were skint, I would have the speed & depth package instead.)
One caveat is to beware of bit players in this market selling poorly-engineered stuff and then bailing out on the customers...
Stick to the stronger long-term companies like Raymarine or Furuno, with good tech support and basic product engineering for salt water usage on board actual boats.
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