Which depth sounder? In hull or through hull? Cheap or dear?

[Koeketiene]

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I had a NASA target for several years in an oil filled tube bonded to the rather thick hull. It always gave up at about 30 metres depth.

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Jeez - how much do you draw?
Whether you've got 30 or 50m beneath the keel surely is irrelevant.

I once commented to the HM at Ramsholt that I had only 20cm beneath the keel when crossing the Deben bar.
He looked at me and said: 'How much water do you need?'

 

[billcole]

Some of the transponder's acoustic power, and some of it's sensitivity to the returning echo, will be lost when it is internally mounted rather than through the hull, and so the maximum depth of water that can be sounded will be a bit less, so if you were wanting to use the sounder for navigation as in navigating along a contour in deep water or suchlike then it might be worth mounting through the hull.
If like me you just want to know how close to the beach or the estuary bank you can go before tacking then the reduction in the maximum soundable depth won't worry you !

 

[Andrew_Trayfoot]

You may not think that you want a fish finder, but you will get a far better piece of kit for your money than the NASA offering.

The Garman ones are made in much higher volumes, for the US market, than NASA, so the economies of scale mean a far better product for you money. Just place the two items together and you will see what I mean.

The Garman Fish Finders are:
1. Flush Mountable
2. Waterproof
3. Have Volt Meter
4. Multiple Alarms
4. NMEA Data out...
But the biggest advantage of a fish finder is that you get a graph showing the depth trend (is it getting deeper, shallower, contestant) without having to remember the reading last time you glanced at it..

And also it keeps the kids happy looking for the fish!!!

 

[webcraft]

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How ugly an appendage is that NASA?! Another good reason to epoxy inside.

[/ QUOTE ] Are you worried about the fish laughing at you?

Ours is flush with a wooden fairing bonded to the hull - looks fine if you are worried about the appearance, and protects the transducer as well.

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- W