Transom Mounted Transducers

[boristhebold]

Im looking at installing a new chart plotter and was thinking about also upgrading my depth sounder if worth it.

My quick question is does anyone using a transom mounted transducer not suffer with the depth reading cutting out above certain speeds. Mine currently drops out when I reach about 20knots plus and in some weather conditions, so if they are all prone to this I will stick with my current depth sounder set-up and just buy a new chartplotter to replace my old plotter that I can no longer get up to date maps for. If there is a great transom mounted depth sounder set up that some people use and it works then I will consider changing to it.

Its not a major problem as I do look at my charts and anywhere near cliffs or beaches etc im usulaly going at a snail pace so not an issue as reading is ok, but you know whats it like when you rushing a long, an accurate and constant depth reading is a comfort factor.

[jyasaki]

It's a matter of playing with depth and location until you get it in a place and orientation that works.

I've got a Lowrance 525; it reads depth and contour at WOT (around 40mph), though with reduced detail (as far as I know that's normal.)

Most installation manuals say to initially locate the transducer centerline even with the hull; I think mine is a tad higher than that. Really depends on the boat you've got it on, as some may run more bow up or down at cruise than another does.

jky

[longjohn]

Mine works pretty much at all speeds - tho' obviously not when I'm airborne! It does take a little trial & error to get the setup just right I guess will depend on the hull shape of the boat in question.

[Searider]

My garmin fishfinder works well at all speeds unless its dirty.

Mounted about halfway between centre and chine away from sprayrails.
Quite deep - possibly 20mm below hull surface. Only downside is it does kick up quite a bit of spray.

[kerny]

Originally Posted by longjohn

Mine works pretty much at all speeds - tho' obviously not when I'm airborne! It does take a little trial & error to get the setup just right I guess will depend on the hull shape of the boat in question.

Mine is fitted in the exact same place as yours but I do find that it flicks up now and then and its as tight as i can get it.

[mick]

Originally Posted by kerny

Mine is fitted in the exact same place as yours but I do find that it flicks up now and then and its as tight as i can get it.

Ours is in a similar spot and is rubbish especially the depth gage

[Chris]

Can you glue the sender into the hull? It's gets it off the transom and will generally give much better results..

[simon23]

Originally Posted by Chris

Can you glue the sender into the hull? It's gets it off the transom and will generally give much better results..

This was surggested to me when i broke the mounting lugs off my garmin,belive as long as their are no bubles in the glue they work well.will be trying it myself in the next few weeks

[9D280]

+1 for longjohn's setup. (WRT the "chines"). As per everyone else, It took a bit of tweaking!

I Sikaflex-ed a 1/2" wooden block painted in International Paints' "rescue orange" (just to blend it in!) onto the hull, and had to re- drill it three times before I got the optimal setup. I am also about to fit a "spray hood" to the wooden block as the "Belagio effect" has resulted in a spray plume that jetski drivers are envious of!

Works fine up to 30 knots. It might work above that speed, but I'll need a bigger engine to find out!

[boristhebold]

I think the concensus opinion is that transom mounted transducers (depth guage) are a bit of a hit or a miss, they need fine tuning and depending upon location and make get mixed results from people.

Generally Hull mounted are a better option.

I will play around with tweaking the position of the transom mount I have and will also investigate the possibility of having a hull one fitted when I am about to upgrade my chart plotter, if feasable I will add a depth guage capability to the new plotter with a hull transducer and keep my old plotter fitted with the existing transom mounted transducer. That way I will have a complete back up system and the option to full screen both plotter and depth guage .

[Screaming04]

Just take your transom mounted unit and epoxy it to the bottom of the hull. I've done two this way, excellent results at all speeds. Saves your transom from future water ingress as well.

[tonto]

I took the advice from a previous thread, and silicon'ed the transducer into the bilge well at near the bilge pump.

I built up a dam from modelling clay, and filled it with a good thick layer, and made sure the ransducer was horizontal as possible, and no air bubbles were in the silicon, and left it to set.

If it was not right I could have redone it, but it was fine.

It gives a good reading, even at near WOT.

When I got the Rib the transducer was fixed half way up the transom, so over 5 knots it didnt work................

[jyasaki]

Originally Posted by tonto

When I got the Rib the transducer was fixed half way up the transom, so over 5 knots it didnt work................

I could see that not working.


jky

[Portnahaven]

Originally Posted by boristhebold

I think the concensus opinion is that transom mounted transducers (depth guage) are a bit of a hit or a miss, they need fine tuning and depending upon location and make get mixed results from people.

Generally Hull mounted are a better option.

I will play around with tweaking the position of the transom mount I have and will also investigate the possibility of having a hull one fitted when I am about to upgrade my chart plotter, if feasable I will add a depth guage capability to the new plotter with a hull transducer and keep my old plotter fitted with the existing transom mounted transducer. That way I will have a complete back up system and the option to full screen both plotter and depth guage .

The secret is to get the cleanest water flow over the transducer, with the least turbulance. In my old boat i had to move it three times to get best results. Even filled a very tiny gap between transducer and hull with silicone, which improved results - slightly

[wavelength]

As an experiment-if you've got a drain well at the transom, so there is a single layer of grp between the water and the transducer, put your transducer in it and throw a bucket of water in there with it. Just lodge the transducer in place with a bag of sand or sommat if neccesary although I've never found that required and see how it works. It should work fine even at speed-and one of my fast fishing boats ran like that for years-just launched and chucked a bit of water in each time. If it works dry it all out and squeeze a dollop of silicon into the allocated place, push the transducer hard down into it with a bit of a twist to get rid of air bubbles amd let it cure. It'll be fine-even though the books will say don't use silicon it works with no problems and can easily be removed if you decide differently later.

[Pikey Dave]

The Raymarine installation manual for in hull txrs suggests just sticking them in a plastic bag of water & positioning them in the hull until you find the best echo. Then place the txr on a bed of KY jelly to confirm the positioning,if that works ok, epoxy in place.

[Barfly]

I have a through hull system and stepped hull

I can say, this works till 15kn... ;-)