Depth Finder

[gbb]

I need to get a depth finder for my whaler. What features would I be looking for in a depth finder for the back bays, shallow water. Mainly fishing flounder.

 

[triumphrick]

Re: Depth Finder

Are you not looking for a combo unit? I have had Hummingbird and Lowrance over the years. Lot's of good things said for both, as well as some not so happy...
The screen size is going to determine the price range. For me and my tired 'ol eyes, nothing smaller than 5" screen. My last two have been combo units and were Lowrance and I found them pretty intuitive. Sidescreen and higher definitions are going to cost more.
I run two units on our boat, Lowrance lms 520 and a Lowrance lms 522. Neither one is available now..both been replaced by the newer hds systems.

 

[Pez Vela]

Re: Depth Finder

What other information besides water depth would be helpful in your pursuit of flounder?

As your need for information increases, so does the desirability of enhanced performance and additional features. Your intended use suggests that virtually any unit would suffice, and at that point, screen size and price may become determinative. You probably do not want to pay for a lot of powerful features that you'll never need and seldom use. For shallow water bottom fishing, you probably only need the most basic "low power" unit (400-500W) with a single element (200 kHz) transducer. If water temp is important, you'll want a transducer that provides it. If you'd like the flexibility to read in deeper water, then you'll want a dual element (200/50 kHz) transducer.

I think you should be looking for ease of use, and to determine that, only you can decide by comparing various units, side by side, in your favorite marine store. Just about every unit built by a competent manufacturer will have more features than you need.

 

[jhebert]

Re: Depth Finder

The only influence of your Boston Whaler boat on this topic will be to force you to use a transom mounted transducer.

 

[gbb]

Re: Depth Finder

I am going to the boat show tomorrow to check them out. So, just a 20degree transducer should be fine. Depth is very important there, sand bars everywhere.

 

[Pez Vela]

Re: Depth Finder

Realize that a wide 20? beam width 'ducer will be a 50kHz 'ducer, which provides relatively less detail, but covers a larger swath of the bottom than a narrow 6? beam width 200 kHz 'ducer. A 200 kHz 'ducer is indicated for extremely shallow water. There's really no reason to make a choice, just get a dual element 'ducer, verify that the sounder displays each, and can also display both simultaneously in split screen mode, and be done with it.

 

[dingbat]

Re: Depth Finder

When flounder fishing you need to be able to see the bait hovering right above the bottom. Most of the time you can?t mark them. The only indication that they are there is the disturbed water surrounding them from their fin movements. Next to impossible to see on a B&W unit if at all. Need a very sensitive unit with good separation capability to see the bait. On my FF the schools if biat show up as a very light blue haze sitting on the bottom.

Be warily of the advertised cone angles. Some of manufactures rate their cone angles differently others. To measure a cone angle, the power is first measured at the center or axis of the cone and then compared to the power as you move away from the center. When the power drops to half (or -3db, the angle from that center axis is measured. The total angle from the -3db point on one side of the axis to the -3db point on the other side of the axis is called the cone angle.

This half power point (-3db) is a standard for the electronics industry and most manufacturers measure cone angle in this way, but a few use the -10db point where the power is 1/10 of the center axis power. This gives a greater angle, as you are measuring a point further away from the center axis. A transducer that has an 8 degree cone angle at -3db would have a 16 degree cone angle at -10db.

IMHO the only way to go if your serious about flounder fishing is a digital unit that you can run in manual mode. My pick would be one of the small Furuno (FVC 620) or Raymarine units. The HDS might work as well but I?ve never seen a HDS unit in manual mode.