Help with Depth Soundings

boristhebold · 27 September 2010, 08:32

Any one got any good tips about how to adjust the depth sonar, my unit displays depth ok at low speed under about 10 knots but anything over it just gives up, I imagine its the angle of the sounder but ive tried adjusting and its driving me crazy.

BogMonster · 27 September 2010, 09:45

Where's the sounder physically attached? I had much the same problem with my Humber except it was 20 knots ish, I think it was because it was half way up the transom towards the tube and so at higher speeds it was in the confused water flow off the hull at speed, rather than being in clear water near the keel. I messed about with the angle but it didn't seem to make much difference.

The Vipermax has a through-hull transducer which is probably the neatest solution if you can do it

willk · 27 September 2010, 11:51

What type of Transducer is it and what age is it. Show us a pic of it's position on the transom.

As the Bogwotsit said, it should be away from other items, in clear water flow below the keel. I don't think the actual angle should stop it working at speed, just give slightly "off" depths. Does it recover quickly when you slow down???

wavelength · 27 September 2010, 13:58

take the transducer off the transom if thats where it is. Throw some water in drain well and put transducer in there with it-keep it propped upright with something. It should work fine then sounding thru the hull (never mind if its supposed to be an outside one they still work). If so dry drain well out and stick transducer down with some clear silicone sealant ( the books say dont use silicone use two pot epoxy-ignore books! With silicon it works fine and you can get it out again easily). Leave to dry and bobs your wotsit. Ours work at 40knots with no problems.

boristhebold · 27 September 2010, 15:49

Thanks everyone, I also searched this forum and it seems a number of threads on this topic, the concensus seems lots of people have had problems with external hull mounted transducers, the most common fix that works appears to be to shift it inside the hull.

I feel a winter job coming on. Wish the manufactuers would just mount them internally to begin with.

Thanks

Pikey Dave · 27 September 2010, 17:10

Ideally you need an area of hull that has no balsa or foam in it, solid GRP

wavelength · 27 September 2010, 18:46

it'll ony go thru one layer of material. And it wont go thru air or gas bubbles. The drain well is the place - it should be solid there. My fishing boat never had the transducer bonded in and at every launch over the beach the first job after starting up was to sling a bucket of water in the well. Worked fine and it could be taken out and taken away with us if using someone elses boat when we went to Ireland etc

Scousedeli · 10 October 2010, 14:37

I hope this does not sound like a daft question, but would this fix work when fitting the transducer inside the hull on a searider even if it directly in fornt of the engine?

Cheers

Lee

willk · 10 October 2010, 14:41

Quote:

Originally Posted by Scousedeli

I hope this does not sound like a daft question, but would this fix work when fitting the transducer inside the hull on a searider even if it directly in front of the engine?

I believe a lot of these terrifically innovative searider chappies do just that, running the cable over the transom into the draining hull and then gluing it to the bottom.

Downhilldai · 10 October 2010, 14:48

I think flooding hulls are daft, but if you want to retain that quirky feature, a transducer in front of the hole would slow the rate of escape of water, when the boat comes onto the plane.

wavelength · 10 October 2010, 19:31

should be ok. Try it with silicone first - it may or not be strong enough a bond in there for permanent use but if you try it and its no good you can peel it out again. Silicone may indeed be good enough for the permanent fit. Don't mount it so its trying to sound thru the keel itself there may be other stuff in there. A tad to one side will be fine. (Thats an imperial tad not a metric one cos I'm an old git!)

C-NUMB · 10 October 2010, 20:08

I did position some years ago a transducer, sounding through the hull. Made kind of a semiclosed well, filled with ricin oil. It was fully inside the hull, nothing went through. It worked ok for years until sold the boat. The design was a direct copy of the manufacturers version( expensive) but cant remember the brand. It was essential to get the transducer in a straight vertical position.

wavelength · 10 October 2010, 20:32

seafarer used to market the tube and fill with oil-aint neccesary and not practical in the flooding cavity of a searider. Transducers are not difficult to put in with silicon- just get on with it and do it, if it don't work (but it will) just peel it out.

Quote:

It was essential to get the transducer in a straight vertical position.

its really not that critical

C-NUMB · 10 October 2010, 21:06

Quote:

Originally Posted by wavelength

seafarer used to market the tube and fill with oil-aint neccesary and not practical in the flooding cavity of a searider. Transducers are not difficult to put in with silicon- just get on with it and do it, if it don't work (but it will) just peel it out.

its really not that critical

Yes, it was probably a seafarer. Fully agree, not a very practical solution on a SR.

Was out today and berthed for a coffee break on a shallow beach. No damages but decided two things, flooding hull has to go and need to have a depth sounder on the boat. Millions of underwater rocks here, the less draft the better.

Guess gluing a transducer with silicone before closing the hull might be a convenient way to do the installation.

njensen · 11 October 2010, 12:14

silicone sucks..... sikaflex rocks...

much stronger, better adhesive capabilities, better sealing....

Silicone only belongs around your bathroom sink... or in some medical/fysiological usecases....

9D280 · 12 October 2010, 16:25

Quote:

Originally Posted by C-NUMB

Guess gluing a transducer with silicone before closing the hull might be a convenient way to do the installation.

....until you need to get at it for service / replacement!

wavelength · 12 October 2010, 16:40

Quote:

Silicone only belongs around your bathroom sink

b*ll*cks

C-NUMB · 12 October 2010, 17:03

Quote:

Originally Posted by 9D280

....until you need to get at it for service / replacement!

That is also correct!

Maybe due to bad luck or condense issues(due to huge yearly temperature variations), but always seams to get water in closed double hull spaces, sooner or later, in my boats. So will either block the drain hole with a removable "flange" or then make a inspection hatch in the deck.

Don't know much about modern depth sounders, how good are they to measure the depth
in front of the boat, as that is the most needed feature for me? Is it a problem to have it close to the transom or should I fit it closer to the bow? Thanks

jyasaki · 12 October 2010, 18:33

Quote:

Originally Posted by C-NUMB

Don't know much about modern depth sounders, how good are they to measure the depth
in front of the boat, as that is the most needed feature for me? Is it a problem to have it close to the transom or should I fit it closer to the bow? Thanks

Too close to the bow and it won't have water to shoot into at speed. Not sure the few extra feet are going to give you whole lot of warning when the water gets skinny in any case. That does, of course depend on your rate of forward motion as well.

My ducer is mounted off the transom; I was thinking about getting a portable depth finder for those times when I am in a shallow rocky area, and have someone hand-hold it in the water off the bow.

jky

BogMonster · 12 October 2010, 23:03

Quote:

Originally Posted by C-NUMB

Don't know much about modern depth sounders, how good are they to measure the depth
in front of the boat, as that is the most needed feature for me? Is it a problem to have it close to the transom or should I fit it closer to the bow? Thanks

They shoot pretty much straight down I think, but you can get forward sounders at a price, there was an article about them in RIB Intl a couple of years back, have a look at something like http://www.echopilot.com/ for an idea of what they can do.

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