mid cabin - thru hull transducer location

BobCT · Post by **BobCT** » Sun Aug 14, 2011 5:24 pm

I have an ongoing issue with my Raymarine L760 giving erratic readings primarily at cruise speed. Two different units, two transducers, new power, ferrite chokes, re-routed trans cable. You name it, I've tried it.

The consensus between Raymarine and Airmar is the transducer location which is the only thing that hasn't changed.

Can you guys give me a rough idea where your transducers are in the hull? It's a lot of work to move it so I have to think long and hard whether I want to go through the effort. Mine is on the Stb side, within a foot of the stuffing box and almost next to the stringer that's parallel to the gas tank.

thanks

Bob

P.S.- it's technically a "Triducer"... speed, temp depth. It's a bronze unit with the fairing block (which made no difference).

RWS · Post by **RWS** » Sun Aug 14, 2011 9:29 pm

I'll look for a photo

RWS

RWS · Post by **RWS** » Sun Aug 14, 2011 9:50 pm

Bob,

Remember, this is the Express, not the Mid Cabin, but the concept should be similar.

First time around I had no fairing block, and was shooting at a slight angle.

In this location turbulance has not been an issue.

Access inside the boat is via the lazerette, the transducer is close to the inboard stringer.

Hope it helps.

RWS

koviak · Post by **koviak** » Mon Aug 15, 2011 8:17 am

Mine is located 3/4 of the way forward on the starboard side, works great.
Also using a fairing block.

Mike Kulp · Post by **Mike Kulp** » Mon Aug 15, 2011 10:02 am

My 1986 Mid cabin has them located just behind the mid cabin bulk head in the front of the engine room on the outside of the center stringers.

BobCT · Post by **BobCT** » Tue Aug 16, 2011 2:35 pm

thanks guys, that helps. RWS, mine is roughly the same location but on the other side of the shaft log.

Mike, based on your description it sounds like it's in front of the engine. Would that be about right?

Sort of below the alternator on the Stb engine? If I got that right, that's quite a bit forward and towards the center of the boat compared to mine.

Bob

Mike Kulp · Post by **Mike Kulp** » Wed Aug 17, 2011 7:51 am

Yes Bob that is exactly were they are at.

BobCT · Post by **BobCT** » Wed Aug 17, 2011 9:23 am

that's interesting. Both of yours are inboard of mine. Mike, yours is quite a bit forward as well.

It's a lot of work to move it and this is one of those problems that just keeps going on and on. If I do move the transducer, I won't know until next year whether it's fixed or not.

Do either of you have Raymarine units by any chance? I have an older L760 which is my back-up chartplotter but also gives me depth.

Maybe I'll try one of the shoot through the hull transducers first. The deepest water I'm ever in is still less than 150' and I don't fish so it might be good enough.

Mike, if you happen to have a pic of yours either under the boat or in the engine room that would be great.

Bob

RWS · Post by **RWS** » Wed Aug 17, 2011 10:54 am

Hi Bob,

Mine is a RayMarine unit - (although I would NEVER reccomend this brand to anyone)

As far as the shaft logs are concerned, If we put a mid cabinnext to an express, it seems that the mid cabin's shaft logs would be further aft. . . . correct?

Placement of the tranducer on mine was reccomended (as I recall, but cannot be certain) by John Leed at Marine Tech.

It is critical to keep the 'ducer away from turbulence.

That said, when I first got the boat and hauled her, I knew very little and did not use a fairing block. Not only was I shooting at an angle, but at certain speeds i'd loose the bottom.

That was with an older RayMarine unit.

The correct fairing block and or new transducer in the same location made all the difference.

For what it's worth.....

RWS

BobCT · Post by **BobCT** » Wed Aug 17, 2011 12:42 pm

correct on the shaft logs. I was referring to the general location relative to the transducer but they are in a different hull location if you compare the two models.

The transducer that came with the boat didn't have a fairing block. When I wrecked it last year on a rock, the new one came with the fairing block which I was sure would make a difference. No change at all. My downward angle has been good in both places.

I'm leaning more towards a shoot thru the hull model as a test. I can leave the other one in place and see what it does. My winter list is getting long again but I should probably do this first.

Bob

Allen Sr · Post by **Allen Sr** » Thu Aug 18, 2011 5:24 am

I would stick with the thru hull transducer. I have a sh*t thru the hull that gives bad readings. Plus it lies about the fish worse than any fisherman I have ever met!! This winter I am changing over to the thru hull due to the fact I don't find the current one dependable. Nothing like going into new areas and have the depth reading quit or jump around erratticly. JMO. FYI I am running a Garmin 740s with a Garmin 235 as a backup. The 235 is more reliable, and it is a thru hull.