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**David M** · 09-01-2008, 11:12

You can buy wedges from the manufacturer that will get your sounder pointed close to straight down...or if you are creative you can make your own out of a durable plastic.

Transducers create a cone measured in degrees. If the cone is pointed towards the bottom then you will get a return. I ideally you want it pointed straight down because when the boat rolls you will maximize the amount of time the transducer is getting a return but you can get away with some angle to the transducer.

All boats that are not tiny little things need a sounder. It's just good seamanship and safer to have one. Many boats have two, they are so basic to safe navigation.

**Boracay** · 09-01-2008, 18:06

The boat came with a fairly ratty looking ST30 Bidata display (not installed).

I am assuming it will work with a ST40 depth transducer.

Should I use this or would I be better off going to a new ST40 Bidata or individual speed and depth displays?

**Ex-Calif** · 10-01-2008, 01:52

The first and only electronic instrument we have is depth. Having someone on the bow with a lead line sounds traditional. Apparently you can also still send communications to people on something called paper, that you stuff in an envelope and affix something called a stamp to, although I don't know why you would want to...

Sandy bottoms move - most charts are old. Many coastlines are not even surveyed that accurately.

Unless you plan a cruising life 12 miles off shore and running in with the dink, get depth...

**Pblais** · 10-01-2008, 03:15

Quote:

Should I use a secondhand ST30?
The boat came with a fairly ratty looking ST30 Bidata display (not installed).

Here is what I would assume. The old ST30 display used to work. When it no longer worked it was removed. I'm not think a PO would uninstall soething that worked. It may have been that the transducer quit but they didn't want or could not figure out which end was bad. I would not assume the transducer is still good or that the display still works.

If you buy an ST40 Bidata it comes with the transducer(s). If you bought a second hand ST30 bidata it still may not work and that is the more expensive part. A quick check on eBay didn't turn up any displays but the transducer is the same as the ST60 so if the transducer is good it may work but the cable may be different.

Steve Kidson · 10-01-2008, 19:38

I am nearing completion of my re-fit and at same time have installed tranducers for depth and log.

I opted for Navman instruments and installation instructions for depth transducer included for the following:
Position ahead of keel
Position in an area not affected by turbulence/cavitation etc
Ideally pointing straight down; if not, no more than 15 degrees off centre.

I made (shaped to hull curvature) a wedge from cedar, epoxied to hull and faired area with an epoxy putty.

In my opinion, a depth sounder is a madatory piece of equipment for cruising. The old timers would not have left port without a lead line, our electronic age has replaced it with a transducer and display; use the technology.

Fair winds

Steve

Seeratlas · 10-01-2008, 21:16

Along the lines of improvements in technology for the same purpose, has anyone actually worked with the Interphase arrayed sonar/fishfinder/depthsounder setup?

I'm very curious about whether it works as I've often thought about what would happen if you aimed a transducer slightly down and forward of the boat. Would the depth alarm actually work to let you know a few seconds before you struck something not visible from the surface?

seer