Randy, I think I might try that 140 unit, since the cost is reasonable if you don't have to buy a second transducer. I don't have my boat at home, but my only recollection of a cavity is just aft of the tube where the swing keel control line runs down. We keep our wine just forward of the battery, so we have not investigated the other location much. Fact is, I have not poked my nose into every nook and cranny yet, so it is about time. Thanks for doing the experiments and passing the results along. It's snowing like crazy out here in the Sierra Nevada, so I have to get out and play with the snowblower. Enjoy your share of the white stuff. Tom Jenkins On Dec 11, 2009, at 5:35 PM, R.K.Graves wrote:
Hi Tom,
Yes, the transducer that comes with the Garmin 90/140 is intended to be used to mount the transducer onto the transom. That is the transducer that I am using on our M17, but mounted it to the inside of the hull rather than to the transom (did the same with the Eagle). For testing I took silly putty and "stuck" the transducer in different places inside the hull and tested. But for my final installation I placed the transom in the empty space behind the keel and submerged it in a couple inches of water (no silly putty or silicone). This give me the best performance to-date. The water does evaporate over time. I was thinking beta 3.0 might be to submerse the transducer in a couple inches of vegetable oil.
Expecting snow here in Idaho! Thank you for the Christmas greeting!
Randy Graves
On Fri, Dec 11, 2009 at 4:57 PM, Tom Jenkins <tjenk@gte.net> wrote:
Randy, Very informative. I gather that the 140 comes with a transom-mount transducer, and you used an in-hull model. Which transducer model did you use? Merry Christmas to you too! Tom Jenkins
On Dec 11, 2009, at 4:34 PM, R.K.Graves wrote:
Harry & Nancy,
This past August I re-visited the depth sounder/fish finder installation on our M17. As you mentioned, my goal was to not drill a hole in the hull and still get good depth reading. My first attempt (beta 1.0) was using an Eagle Cuda 242. with this unit I had mostly-reliable reading securing the transducer to the hull in a couple of places. Oddly enough the depth readings were unreliable in water shallower than 15ft.
Not fully satisfied with my beta 1.0 results, this past August I found a store with a good return policy and after much research purchased a Garmin Fishfinder 140 (displays depth, battery voltage, and water temp.). I'm very happy with the beta 2.0 results! Good reading is both shallow and deep water. And very good detail of the bottom contour.
The Transducer location that gave the best performance on our 1988 model M17 is the cavity area just aft of the keel (the place Tom Smith calls the wine cellar). In their I placed the transducer, and for A+++ performance added a couple of inches of water submersing the transducer. The 2nd best location, which may work well on the M15, is the flat area in the middle of the hull just aft of the keel. This is the flat area which eventually forms the skeg. I sanded off the interior gelcoat and using some silly putty as a temp. adhesive also had very good results there.
My conclusion is that good thru-hull depth performance is first a function of the vendors transducer, and secondly a function of location. Early on I was convinced performance was a function of a dual-frequency transducer versus a single-frequency transducer, having seen the single-frequency Hummingbird unit perform very well on Larry Yakes boat, easily reading to 300+ feet.
If anyone is looking for an exceptional deal on a used Eagle Cuda 242 please email me off list!
Merry Christmas to Everyone, Randy Graves M17 #410
On Fri, Dec 11, 2009 at 1:09 PM, Harry & Nancy <nanarry@shaw.ca> wrote:
Hi folks: Re M15 and installing a fish-finder. I've tried to find some info. on our site and the most reassuring( to me, that means no hole in hull) is from Randy Graves posted Dec.27/08. Of particular interest is location of the sensor.Randy, if you or anyone else has tried placement aft of the centreboard,I'd much appreciate learning of your success. As I discovered this past summer on L. Superior, rocks and "Li'l Nan" don't mix! _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/ montgomery_boats
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