GPS Antenna and Transducer mounting

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J

Josh

Where does everyone mount their GPS antenna? Where's the best place to keep it from being blocked by all the rigging of a sailboat? Also, what's the feeling everyone has on transducers? I've read a lot about people mounting them against the fiberglass of the hull. The idea is that it gives you some warning before you hit something. A transom mounted one would tell you what you just passed over which does you little good. My question I guess is what good is finding out what you are about to collide with a split second before you smash into it? How does the transducer compensate for the angle that it has placed on it by the curvature of the hull? Although this curve would give you better warning of something looming ahead of you, it would be greatly inaccurate as far as depth and distance wouldn't it? Do you just mount a transom transducer to shoot through the fiberglass hull, or are the stories I read about how to do this done with special transducers? I guess I'm leaning towards a transom mount, because if anything it will tell me that the ground is coming up. The speed sensor and temp sensor won't work through the hull either. The only thing that it wouldn't warn you of is a near vertical rise. I almost wish they made a transducer that could mount outside the hull without having to cut a hole in it. Hmm..thats a good idea...that idea is patent pending now! hahah... Seriously, any help would be appreciated. Just bought the boat, and now it's time to accesorize! I'm looking at the Garmin MAP 168 if that helps anyone. Thanks again, Josh
 
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Russ Marcks

Transducer mounting

I don't use an external GPS antennae (I have a GPSMap 175) so I can't help you there. As far as transducer mounting is concerned, I wouldn't worry about mounting it in a position to warn you of an impending grounding. First off, depth transducers are designed to look straight down and to be installed near vertical. The degree to which you can mount off vertical should be stated in the installation instructions. If mounted outside of those recommendations, they don't give accurate readings anyway. In fact if mounted to far off vertical, the error is such that the reading may show deeper water than you actually have. Second, we all should be using charts to ensure we're not in water to shallow for our boats. There are to many variables that can affect the readout. For example, depth transducers are affected by large masses of underwater seaweed, extremely turbid water, etc. I see this all the time where I sail; all of a sudden the reading goes from 12 ft to 3ft of water. But I know we currently have a problem with seaweed. In most cases, the bottom does not rise so rapidly that you cannot detect that rise with a depth finder to avoid a grounding. Use you depth finder coupled with charts to show such trends. Not to mention, if you're that unsure of the depth, very slow speed and a weighted
 
J

Josh

Transducers...

The GSMAP 168 is supposed to be a fish finder actually, but didn't state anything about looking forward. Also, they didn't specify any transducer for shooting through fiberglass. I wasn't planning on using the through hull for that, I thought about epoxying the transom mount though... As far as charts, thats soemthing I plan to get as well, but the more accurate equipment you have the better off you are! How dows your 175 work with the sails and such being in the way? Does it just have the internal bail antenna? Thanks, Josh
 
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