Sounders-transducer depth dropout

[Snap]

I bought a LS6100 Furuno sounder last year & I am having probs with the transducer losing the bottom at varying speeds.
Sometimes OK at 20knts then not, this can also occur when moving as low as 10knts.
I know that it depends a lot on the sea conditions and how well your transducer is set up but I followed the mounting instructions to the letter & all looks OK. >:(
Any suggestions more than welcome.
Plus I remember an article on fisho's somehow fitting plates around the transducer to stop turbulance, Does anybody have any info on such modifications. ;D

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If there aren't experts, I will settle for best guess ::)

[davo189]

Hay Snap, any chance that you could post a pic of the T/D setup showing how and where it is mounted? The 6100 is a excellent unit - I have a 4100 (little brother but same power & t/d) and it is great and sounds well even at 40 knots.
Davo.

[Big_Kev]

Your transducer is most likely getting interferance from the boat wash.
Try moving it to another spot and angle it down hard at the trailing edge.
Cheers Kev.

[Hagar]

Yeah Snap
there is a lot of experience on this board . Give us a pic from behind and side on of the xducer mounting and we will give you a best guess . Chris

[adamleah]

I have a haines signature and found that the hull rose out of the water a fair way when planing . this therefor made the original transducer come actually out of the water ...I have now mounted the new unit pretty close to the V and only lose depth sometimes when it gets up over 30knots...

[Snap]

To Davo189, Reel Hard, Hager & Adamleah thanks for your reply. I will bring home the digital camera tomorrow night and take some picks.

Adamleah; I've had the hull out of the water a few times crossing the south passage bar :o a bit too heavy handed on the throttle, next time my wife comes out I'll get her to hang over the back to see if the transducer comes out as well. ;)

[Snap]

Here are the pics, note the old holes to the centre of the boat were there when I bought it but the 2 hummidbird transducers were postioned either side of my current Furuno one. Obviously he had trouble with prop disturbance that close.

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next

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and another

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last one,

[peterbo3]

Hi Snap,
The pics may be deceptive but it looks like the transducer is higher than the foil. This will cause the TD to nearly out of the water on the plane, hence your problem. Drilling more holes in a FG transom is hit & miss. Suggest you get an alum bracket made up, screw that to transom & then you drill holes to you hearts content until you find the best spot. You can see a pic of a transom bracket in my thread of Lightning C/C Modifications. Hope this helps.

[aido]

you've got a nice flat keel (strake??), maybe you could
epoxy a short length of pvc sewer pipe inside the hull,
fit the tranducer low inside that, cover the unit with
glyerol from the chemist shop and put a cap on the open end
of the pipe.
had that setup on my last boat, and it was great, bottom locked
right up to top speed 80+ kph and never missed a beat.
shame not to have your furuno working at it's best.
aido.

[Snap]

Thanks Peterbo3 looked at your thread, nice job on the blunt end. Interesting to see how close the TD plate is to the center. I read on my mounting instructions that you must keep it out of the prop area when straight & turning width, if that makes sense.

[Hagar]

Snap
Agree with the other guys observations . Your xducer looks to be mounted too high. You do not want to go drilling holes willy nilly in your glass transom so you need a bracket or plate which is adjustable up and down or which you can drill holes in and not affect your transom . There are detent - type up / down sliding brackets available at marine outlets you could use . It's only too far down if it throws too much spray up from the xducer around the outboard at speed .

Chris

[Snap]

Thanks, just looked up Whitworths book I have handy page 61, depth sounder transducer brackets Alum $9.99 & SS $49, I will investigate.

[Hagar]

Hey Snap
Just an observation of the last pic . The left over holes from the previous transducer mountings are a real problem for water ingress into the transom . Looks like some sealant on them . When you have finished with the transducer mounting for good might not be a bad idea to blank them off with stainless screws and some good sealant mate .
Chris

[Mudcrab]

I've got a Whittley Sovereign and eventually finished up putting the transducer in the worst possible position imaginable i.e. right in front of the prop - works like as dream! Like the other guys, you seem to have a rounded transom/keel line? Or is it straight. Rounder ones are mongrels to fit a transducer. Definately would invest in the sliding type as you can fiddle with it till you get it right

[Needmorerum]

While on the subject of T/D's. Hagar, you say if it is too far down it will spray water up. I have mine set up that way, I have even made a S/S cover to go over the top to prevent the water being sprayed onto the motor. I have a flat bottom hull and find that if I lift it up at all then it doesn't work at speed as the flat bottom has bugger all in the water when at WOT. I don't think that this is a problem, it was before I put the cover over the top of it, I can post some pics if anyone wants to look at this.
Would like to know if others with flat bottom hulls have the same experience.

Corry

[Snap]

I've got a Whittley Sovereign and eventually finished up putting the transducer in the worst possible position imaginable i.e. right in front of the prop - works like as dream! Like the other guys, you seem to have a rounded transom/keel line? Or is it straight. Rounder ones are mongrels to fit a transducer.

Could you send a pick of the stern.
Hung my head over the back on Sunday going to deep tempest, bloody white water everywhere my boat will look like swiss cheese by the time i'am through.