Harry, Sounds COLD in Thunder Bay Brrrr! I think a person can get the full benefit of the depth sounder without having to mount the transducer outside or through the hull. For a more forwarding-looking signal I think the location Gary Hyde described would do the trick! I believe the location Bob described is roughly the same place as well. There is an alternate suitable location on the M17 under the v-berth, roughly at where your knees would be from the bow and I am guessing the M15 would have roughly the same location. It is where the curve of the bow transitions into the bottom of the hull. The fiberglass is thicker in this area but I was able to get suitable and consistent forward looking depth reading, but not as good of a bottom contour reading. Some things to think about when considering transducer location vs displayed information. The signal angle from the transducer is quite large allowing you to see a larger area under the boat than you might at first think, depending on water depth. The update speed of the charted display may or may not be useful in seeing underwater obstacles while motoring or sailing. Both units I tested determine water depth from the return signal directly under the transducer. While sailing I found the numeric depth display the most useful information. When anchoring I found the display of the bottom contour and depth the most useful. Displaying of battery voltage and water temp are just an added plus! My thought is to use a glob of silly putting and play with sticking the transducer to different locations inside the hull and see what performance you get before opting for a thru-hull or exterior transducer installation. Merry Christmas, Randy Graves M17 #410 On Mon, Dec 14, 2009 at 7:20 AM, Harry & Nancy <nanarry@shaw.ca> wrote:
Randy: Thanks very much for your prompt reply regarding placement of the transducer.Do you know if threading the cable could be done through the same hole that the line to the swing centre board occupies. If so, then I could mount the transducer farther forward on the outer side of the hull,to enable a more advance warning of rocks- a foreword-looking sonar beam. Also, I think I'll buy the Garmin unit.Thanks again, Randy, and also to others who helped. Not to be out done by our good Yankee friends,since Dec.1,the temp. has hovered between -4F and -10F. All the best! Harry Elmslie,Thunder Bay,Ont. _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
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