Losing bottom P58 tranducer

[JulianDeMarchi]

Hey,

I am having dramas with my P58 transducer losing bottom over 10 knots. My P66 transducer works perfectly in it's spot however.

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Here is the P66 which works fine.
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Here is a close up of it.
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Here is another angle.
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Here is the P58 which I'm having issues with.
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Here is another angle.
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While taking the pics for this post, I noticed under the hull a planning strake(am I correct?), which is directly in-line with the P58 transducer.

On the weekend I added a 9 degree shim to the transducer which improved my reading at speed slightly, but on a very on-off basis. Over 30 or 40 meters it'll refuse to lock bottom and report 13mtrs instead(haven't tested with the shim in place yet). I had this on my old boat and it worked fine in 80+ meters.

I think my mounting is ok though, so this leaves me to think it's the planning strake causing turbulent water around the transducer.

Any opinions?

Thanks!

Julian

[Daintreediver]

I think I have the same piece of shit transducer on my raymarine a70d it works great while idling around soon as you start planing no signal. The thing is way too big compared to others i know with the slim nose lowrance transducers the p58 is the size of a house. And when you put it further down it sprays water all over ur engine. Sorry bout my rant on this transducer good luck with it I gave up on mine after moving it a few times with no results

[Floyd]

Same issue here on our TM258 1KW. Loses bottom around 10 knots. Have tried up to 3 wedges with no success. Ours isn't depth related - will completely lose bottom at any depth once underway. Also have issues with DSM300 losing connection and ping inactive errors. Not a big fan of Raymarine gear at the moment. Will be watching this closely as considering ripping it out and getting a furuno unit fitted.

Daintree - what did you replace yours with? Any DSM errors?

[Daintreediver]

Hey Floyd it is still on there I just gave up on trying to get it read on the plane. It is a great sounder when idling around but all my family who use lowrance on similar hulls ie Haines and yaltacraft work fine at speed and their transducers are half the size of mine and much better shape and design for going thru water the p 58 is like a big square block

[Floyd]

Yeah, frustrating when you want to troll. Ours is fitted behind a water pick up and apparently can't be moved anywhere better so looking at what a thru-hull will cost as well, but with the DSM errors not sure it is worth sticking with raymarine. We are running a C120w with DSM300.

[Floyd]

Julian, hard to see but the 2nd pic does look like the P66 is behind a strake as well maybe? Don't know why it would work if this is the case and the P58 doesn't if it is positioned the same. I guess you could try to play around with the angle before you look at moving it or more expensive options.

[Chimo]

Hi Julian

If I remember correctly when I fitted my replacement Furuno ie P66 I noticed a comment in the instructions about the impact of propellers and the need to fit the transducer on the stbd side of the prop to avoid turbulence

Could this be impacting on your higher speed reading, or lack of it?

Cheers
Chimo

[JulianDeMarchi]

I think I have the same piece of shit transducer on my raymarine a70d it works great while idling around soon as you start planing no signal. The thing is way too big compared to others i know with the slim nose lowrance transducers the p58 is the size of a house. And when you put it further down it sprays water all over ur engine. Sorry bout my rant on this transducer good luck with it I gave up on mine after moving it a few times with no results

Unfortunate about your results. I love my P58, it was a great unit on my old boat and the digital sounder in the e7d gives a great picture. The P66 from Lowrance is the same size, but the headunit is old and the picture is like an old commodore 64 compared to the raymarine. My issue is not with the P58 as I know it is working, and has worked, it's something else about the mount.

[JulianDeMarchi]

Julian, hard to see but the 2nd pic does look like the P66 is behind a strake as well maybe? Don't know why it would work if this is the case and the P58 doesn't if it is positioned the same. I guess you could try to play around with the angle before you look at moving it or more expensive options.

My camera started taking blurry pictures sorry! You're correct about the P66, it's on one too. I'll try the 4 degree on top of the 9 degree shim but I don't think this will help. I think I know the answer but am trying to avoid saying it out loud. I really think it needs to be moved to the left to line up with the P66 mounting position.

[JulianDeMarchi]

Hi Julian

If I remember correctly when I fitted my replacement Furuno ie P66 I noticed a comment in the instructions about the impact of propellers and the need to fit the transducer on the stbd side of the prop to avoid turbulence

Could this be impacting on your higher speed reading, or lack of it?

Cheers
Chimo

This is tru. The way the prop rotates it causes turbulence on the stbd side. I was hoping the half pod on the back would make this an irrelevant point on my boat. But I'm not an expert and only made a guess. No real easy way to test this I spose... This is why I prefer the transom mount transducer brackets, it allows easy removal.

[Fed]

I think the whole prop turbulence thing is an internet myth unless you drive around in reverse gear.

[Chimo]

Hi Fed

It may be but the mob that sell the P66 have been sucked in too

Cheers
Chimo

[Bremic]

The second photo from the bottom, doesn't appear that the transducer protrudes below the bottom of the hull. Could be just the camera angle, if not the transducer won't be in clean water once there is a bit of speed and won't be able to read properly.

[Oceanranger24]

For my 2 cents worth, I think that the placement so wide of the centreline is the problem. the nearer to the outside of the boat, the easier it is to draw air under the hull and lose the 100% bubble free water the transducers need. Any bubbles at all will degrade the performance very quickly. if you simply try smooth water and rough water it will do this as well

Try moving the transducer as close as is reasonable to the centreline of the hull and see what happens.

Getting a reading in shallow water (less than 30m) should be expected up to 25 knots if the water is anything like flat.

Oh and I use a raymarine C90w and have just bought a an E120w to upgrade to.

If anyone is looking for a c90w mine is perfect, currently in the boat for a sea demo should you wish to see it performing..... could even do the demo to the 'shelf' in 450m.

[JulianDeMarchi]

For my 2 cents worth, I think that the placement so wide of the centreline is the problem. the nearer to the outside of the boat, the easier it is to draw air under the hull and lose the 100% bubble free water the transducers need. Any bubbles at all will degrade the performance very quickly. if you simply try smooth water and rough water it will do this as well

Try moving the transducer as close as is reasonable to the centreline of the hull and see what happens.

Getting a reading in shallow water (less than 30m) should be expected up to 25 knots if the water is anything like flat.

Oh and I use a raymarine C90w and have just bought a an E120w to upgrade to.

If anyone is looking for a c90w mine is perfect, currently in the boat for a sea demo should you wish to see it performing..... could even do the demo to the 'shelf' in 450m.

I moved it last weekend to the same position as the P66. It now works flawlessly, well it did to Palmy. 1st of Feb I'm heading wide so I'll get to test her in 100M or so...

[Oceanranger24]

As I said before, give it stick and it should still work. If not I always find near the centre line is the easiest starting point.

ps hope you get a feed out there