Tuesday, October 27, 2015

Low-Cost Depth Finder

Over aboard s/v Cay of Sea, Rick thinks about depth sounders, and replaces his. He keeps the original transducer tho, making this an easy project.
Before our July cruise, I installed the Hawkeye Depth Finder Model #D10D because my previous low-dollar depth finder (Uniden QT 206W) had failed. I’ve had a good opportunity now to compare the performance of both, and can definitely recommend the Hawkeye over the Uniden.

It seems that it is possible to pay up to $500 for a large format “sailboat” depth finder that mounts on the bulkhead. However, the availability of high-dollar stand-alone units is dropping off due to the popularity of consolidated multifunction displays for gps/chart plotter/depth finder/radar displays. And as I’ve looked at the market recently, I’ve noticed what seems to be greater selection among models and makers in the budget depth finder realm. I think makers of marine gear are understanding that the market for high-dollar gear has out priced the budget boaters, and they are now offering more products in the $100-$150 range, which is where I live as well. Don’t mistake this as altruistic behavior on the part of marine gear makers – I’m sure they are more motivated to not leave money on the table by ignoring this large group of boaters.

Regardless, the Uniden model represented a poor value with respect to construction and performance. I had this unit installed on my boat for about four years. After the first year, the display began to suffer from UV and weather-related damage, although it still functioned. The plastic display became frosty, the printed controls lost their readability, having faded in the sun. Finally, the display window cracked, which allowed moisture to enter the unit and make it unserviceable.
All-plastic components with no protective covering provided. It was a UV victim waiting to happen.
All-plastic components with no protective covering provided by the manufacturer. It was a UV victim waiting to happen.

Performance-wise, it was inconsistent at best, but I must say that whenever I absolutely needed to know the depth when approaching shoal waters, it gave me the right information. This may in part be due to my choice of installation. I installed the transducer inside the hull without drilling a hole, and I didn’t glue it to the hull with epoxy – rather, I bedded it in a blob of silicone. I am confident this degraded its performance to some degree. It would never give much in formation in waters deeper than 50 feet, and often in choppy conditions it would return error readings, I assume due to the amount of air passing underneath its location just behind the vee-berth, or the inability of the processor to keep up with excessive motion as found in choppy conditions. When that area was ventilated by air bubbles, I feel sure the device had a more difficult time determining depth. Additionally, it featured a gain, or sensitivity adjustment on the back side, which was extraordinarily touchy.

By comparison, the Hawkeye, while still mostly plastic, features a glass screen. While vulnerable to impact damage, it is nearly impervious to effects of UV radiation, which means that the screen will always be readable. Additionally, it comes with a protective cover which will shield the unit from the sun during the many days and weeks when the typical boat is not in use. I did not install the new transducer that was included in the purchase. Instead, I determine through reading the spec sheet, that both Uniden and Hawkeye used the same frequency and wattage transducer. Not installing a transducer spared me a lot of trouble and effort with the installation. I was also curious how the unit would perform with the old transducer.
New meter from HawkEye - fits the into the same diameter hole.
Depth meter from HawkEye – fits the into the same diameter hole as the Uniden model.

The Hawkeye returns depth measurement much more consistently, with many fewer instances of error reporting. It will also return more depth data in deeper water than the Uniden, although it also has more difficulty with depths larger than 50 feet. Again, my suspicion is that installation mode is a significant factor, and that an external placement would yield more accurate depths more often regardless of the depth of the moment. That said, however, the Hawkeye is significant improvement over the Uniden model. It is less sensitive to choppy conditions, returns readings very consistently in waters up to 50-60 feet deep, and has no gain/sensitivity adjustment. Apparently, the “new improved” algorithms for calculating data are indeed effective, and obviate the need for a gain adjustment featured on depth finders made by other companies.

So at about the same price point (approx. $100 for each) the Hawkeye is a much better value than the Uniden. I feel more confident with this unit on board than I have with any other brand during our ownership of Cay of Sea – and early on, we had a “legacy” Datamarine large-format (read expensive) depth gauge.


  1. Here's what I did for a budget depth finder, and I really lucked out on this one.. I paid a grand total of $30 on ebay. It's over 30 years old - but it was brand spanking new! It cost $272 at the time..


  2. Here's what I did for a budget priced depth finder.. Bought this one ebay for a grand total of $30.. It's over 30 years old, but the condition is brand spanking new! It's cost at the time was $272. Granted, I took a chance on it, but I really lucked out on this one!


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