Help with Depth Soundings

[jyasaki]

Originally Posted by BogMonster

They shoot pretty much straight down I think,

Beam angle of a generic transducer is (as I recall) on the order of 20 degrees or so. The unit shows the first returned echo from within that cone as the "bottom". It doesn't know (or care) if it's pointing down or forward or whatever. If it's pointing severely forward or backward, you get a deeper-than-actual depth reading, unless you don't get a signal back, in which case you lose lock.

The Echopilot thing looks like a side-scan unit turned 90 degrees. Neat device.

Knowing how deep the water is behind you is always something I have regarded as of limited use when going into somewhere you are completely unfamiliar with

True, but even if you knew what was under the bow (i.e. a forward mounted conventional fishfinder), you have to be going slow enough to a) see the display, b) react to it, and c) actually get the boat to avoid it.

jky

[9D280]

If it's that shallow I usually use my patent interactive depth sounder with audible rock warning, which also includes distance data & manoeverability assistance on approach to the hazard.

AKA send the crew forward with the old wooden paddle. If it touches the bottom, its time to lift the engine!

[neil.mccrirrick]

Now that I like, simple, no electrics, highly manoeverable, (they can lean over either side, bow or stern), and has the potential to increase fun in a rib, picking up the patent interactive depth sounder with audible rock warning, when its dropped by said crew

[jyasaki]

Originally Posted by 9D280

If it's that shallow I usually use my patent interactive depth sounder with audible rock warning, which also includes distance data & manoeverability assistance on approach to the hazard.

AKA send the crew forward with the old wooden paddle. If it touches the bottom, its time to lift the engine!

I do a bit of abalone diving, and, being pretty much incompetent at freediving, generally end up in rocky areas with about a 25' max depth. Quite often the shallower rocks are just below the surface (actually, the river we launch out of could fit this as well), so it kind of becomes an issue. I do usually have someone watching, but it's rarely anyone who knows what they're supposed to be watching for.

Unfortunately, the wooden paddle won't work for me, as mine are aluminum.


jky