I have an old fishfinder/transducer that was part of a boat that i bought. I plan to upgrade this to a newer model. I was thinking of selling this when I thought that I could make a "Mcgyver" tidal guage recorder with this.
The unit has an SD card to record depth at various time intervals.
I was thinking of making a still well tube and connecting the transducer to a floatation device placed inside of the tube. The depth recording will be the depth of the water registered to
the bottom of the still well pipe. I could leave the contraption in the field for months as long as the battery is properly charged. If battery is low, it would just take a few seconds to replace & restart the unit.
Is my idea a bit off?
I guess my first question is it accurate enough to matter? It is my impression that most "fish finders" have a lot of slop.
Then how about long term exposure to the elements of the entire system? And building a housing for all of this that would withstand the coastal elements would also be a chore.
You've got the right idea, but I perceive a lot of obstacles to success. But don't let me stop you from trying.
Around here, there's a device at every bridge.
You can access them online, they update the data every couple of hours.
Water Flow.
Water Level.
Water Quality.
that kind of thing.
I look at the water level at lot, especially this time of year when it's really low.
Not sure the transducer will operate normally constrained in a narrow tube, multiple reflections and returns might confuse it. Worth testing this part before you spend too much time on the hardware? I saw a tide gauge recently that measured with a laser down to a disk on the water surface in a tube, everything well above the water in the dry, good aplication for a Leica Disto or similar if there's one that can be modified to record at intervals. I helped calibrate a tide gauge once at a harbour, using the gps base mounted over the harbour bench mark and the rtk rover mounted on a moored dinghy, left it recording at 30s intervals all day then plotted the heights against time. Internal battery didn't quite last the full 12hr tidal cycle but we got enough data for a check.
the Leica disto seems a better gadget. but does it have a model that records to a memory module?including time tags?
Might work
And after 18.6 years of hourly readings, you would have some useful data. That's the period of a complete tidal cycle. Lesser periods of data have little value unless you can relate it directly to simultaneously collected data at a NOAA/NOS tide station. Tide data of just a portion of the tide cycle (a few months) can give misleading results, yielding tide level elevations which may be significantly different from those derived from a complete data set of a full tidal cycle.
So perhaps an interesting hobby, but not much more than that.