Someone recommend a depth finder to me

[thunderroad]

I need to get a depth finder. All I want to know is the depth in feet. I don't care if there is a fish within 500 miles. The smaller in size, the better. I looked at the iboats electronics section and didn't see anything that I really wanted.
It's to go on a 20 foot fiberglass runabout. Do I want a transom mount inducer or a through hull inducer. It seems they say "will work on most fiberglass hulls" when talking about the through hull type. The word "most" kinda concerns me. Mostly I just want it so I'll know if I'm getting in too shallow of water near sandbars on the river.
If I missed something on Iboats, maybe someone can point me in the right direction. If not, let me know what you know about them.
thanks

 

[jtexas]

Re: Someone recommend a depth finder to me

The Eagle fishmark 320 is about as good a value for the $$ as you'll find anywhere. I'd stay away from the entry-level bottom of the line models, but you shouldn't have to spend more than $150.

Transducer is good for transom or shoot-thru-hull (I think most of the low- to mid- range price models come with one like that). If your hull is a foam-sandwich-composite type construction you won't be able to mount it inside the boat - transducer signal won't work through air or air pockets or air bubbles. They say shoot-thru-hull mounts sometimes interferes with the signal - I think its most likely just improper installation. There are tests you can do with your transducer that involve temporary installation under water inside the boat - either fill the bilge & drop it in there, or a plastic bag full of water, or a dam made out of modelling clay or something like that. Drive around & see if you get a good signal. Move it around to find the best location then epoxy it in place.

Transom mount is easy enough & works great and allows you to utilize the water-temp feature, but it's exposed to getting knocked around and maybe broke. If I didn't care about water temp, I'd probably put mine inside the boat.

................just my opinion.

be aware though, that your sonar isn't a ground proximity warning - it'll show the depth under the transducer - more precisely, the shallowest depth of a circle centered directly under the transducer, and a diameter of approx. 1/3 the depth.

 

[PondTunes]

Re: Someone recommend a depth finder to me

Most should mean a non-cored hull. If there's nothing between you and the water but the fiberglass then the transducer will be able to shoot through it. If theres a layer of foam on top of the fiberglass then you'll either have to remove a section of foam large enough to mount the transducer or go with a thru-hull (cutting a hole and mounting it with a fitting) or a transom mount.

By through hull you need to find out if its Shoot Through, or Through Hull, the latter requiring a hole in your hull.

 

[thunderroad]

Re: Someone recommend a depth finder to me

thanks...I learned more in those two posts than I'd learned since I started my search a couple weeks ago. I guess the shoot through type is what I was thinking about but my boat has foam between the floor and the hull except for an area in the bow under the fuel tank. There the hull is exposed in a small area, but it's in a "V" shape. I would guess that the transducer needs to point straight down to be accurate. Is this correct?
I'm thinking the external transom mount is probably what I need to get. I'm really just concerned with how deep it is under my drive.