Through hull or transom mount transducer?

Tammany said:
As others have mentioned just epoxy to the inside of the hull. Just build a dam with plasticine and fill with epoxy and place transducer flat as possible. Mix epoxy slowly so no air bubbles show as this effects the ping.
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You mean like i said in the last post lol
 
I went the full hog on the transducer, made a dam of plasticine levelled it off with epoxy. Put a fresh layer of epoxy in pushed in the transducer giving it the wiggle. Took out the boat 10m fine, then nothing! I do have copper coating that someone mentioned so don't know if that's playing a part. So whilst others have had success it hasn't worked for me. I now have to decide whether to incur the expense of having the bronze through hull transducer fitted when the boat comes out of the water or take it out sell it and buy a simple fish-finder, but I replaced one of those for this:(
 
I bought a Garmin 100 fishfinder with transom mount transducer.
They dont come any cheaper!
Just for fun i pushed the transducer into a wadge of plain old fashioned vaseline on the inside of the hull.

Hull is Glass over plywood and i took a bit of care to try and get a slug of vaseline out of the container without creating air bubbles.
Works up to 180 metres depth so far.
I had been intending to epoxy it, but 4 years later its still stuck in the wadge of vaseline and still working.
I built a coffer damn around it as it is in a locker and it wouldn't take very much to move it, though its more securely stuck in place than you might guess. Yet unlike epoxy I could remove it in a moment and wipe it clean!

I like epoxy for lots of things but think its over complicated and too permanent for this task.
Give it a whirl - vaseline is cheap, quick and easy and if it doesn't work for you, then clean it off and no harm done!
 
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John the kiwi said:
I bought a Garmin 100 fishfinder with transom mount transducer.
They dont come any cheaper!
Just for fun i pushed the transducer into a wadge of plain old fashioned vaseline on the inside of the hull.

Hull is Glass over plywood and i took a bit of care to try and get a slug of vaseline out of the container without creating air bubbles.
Works up to 180 metres depth so far.
I had been intending to epoxy it, but 4 years later its still stuck in the wadge of vaseline and still working.
I built a coffer damn around it as it is in a locker and it wouldn't take very much to move it, though its more securely stuck in place than you might guess. Yet unlike epoxy I could remove it in a moment and wipe it clean!

I like epoxy for lots of things but think its over complicated and too permanent for this task.
Give it a whirl - vaseline is cheap, quick and easy and if it doesn't work for you, then clean it off and no harm done!
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John thanks for the tip but unfortunately this DVS technology which Raymarine and every chandler I speak to, say the only way to get this to work well is to go for the through hull transducer. I do appreciate that older standard fishfinder tech will work well shooting through the hull even with a transom mount transducer. I had such a setup running perfectly well with an old Humminbird fishfinder using a transom mounted transducer epoxied to the hull. But I took that out for the newer (better?) technology, in hindsight I might have been better off just getting a newer basic fishfinder.
 
I must admit I'm surprised.
I'm using a Dragonfly4 pro DV scanner, stuck down on CT1 shooting through what must be 8mm of GRP (it's a 1989 boat) which is copper coated as well.
Certainly works fine on depth, but we don't have much around here to test the DV capability on as it's all just mud.
I had assumed that I was losing a fair bit of signal by doing this, but the humminbird DV transducer on the Colvic was transom mounted and showed exactly the same featureless bottom.
To be fair I haven't tested it in deep water yet (We don't have much of that either) but it was sounding accurately to 60' or so.
But, if it doesn't work, it doesn't work! Maybe it's just a peculiarity of your particular hull, or maybe I just got lucky?
 
Well bit the bullet and fitted the through hull CPT 70 transducer. If size is everything it should be fantastic! It's a big old lump sticking through the bottom of the boat. Boat is out of the water at the moment (obviously) so hopefully the results will be good, assuming the hole doesn't leak :rolleyes:
 
Took the boat out this week got to around 10 m lose depth:mad-new: I ring Raymarine, they casually say (after saying it didn't work before because I needed a through hull transducer!) sounds like a fault with the unit. So having spent nearly £300 on a through hull transducer it looks like the the unit was at fault, thanks for that Raymarine, there was no mention of that being a possible reason the first time I called. Luckily the unit is still in warranty (just) So its gone back to Raymarine for checking. So the moral of the story is if your transom transducer doesn't work stuck in your hull, check your unit before forking out a small fortune and having a big hole cut in your boat!
 
for the dragon fly pro7. What transducer would be best for an Arvor 25. Seen a few on the market but have no idea what to get. Through hull or in hull and what model number etc
 
tonkatoy87uk said:
for the dragon fly pro7. What transducer would be best for an Arvor 25. Seen a few on the market but have no idea what to get. Through hull or in hull and what model number etc
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What model depends on whether you want a chartplotter and fishfinder. You can get it with both or just the downvision scanner fishfinder. Obviously the fishfinder only model is quite a bit cheaper than the chartplotter model.

They both come with a transom mount transducer as standard included in the price, if you want a thro hull transducer you need to add a few hundred pounds on.

This thread started with the "will a transom mount work stuck inside the hull' question. The general user consensus is yes it will, although it didn't for me but after great expense it seems my unit was at fault not the type of transducer.

Obviously you need to mount it in your hull in a suitable way and lots of advice on this has been forwarded on this thread. I would try the transom mount first as it comes with the unit, before paying out for a thro hull, not to mention having to have a great big hole cut in the bottom of your boat!
 
Papasmurf said:
What model depends on whether you want a chartplotter and fishfinder. You can get it with both or just the downvision scanner fishfinder. Obviously the fishfinder only model is quite a bit cheaper than the chartplotter model.

They both come with a transom mount transducer as standard included in the price, if you want a thro hull transducer you need to add a few hundred pounds on.

This thread started with the "will a transom mount work stuck inside the hull' question. The general user consensus is yes it will, although it didn't for me but after great expense it seems my unit was at fault not the type of transducer.

Obviously you need to mount it in your hull in a suitable way and lots of advice on this has been forwarded on this thread. I would try the transom mount first as it comes with the unit, before paying out for a thro hull, not to mention having to have a great big hole cut in the bottom of your boat!
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I don't think it would work transom mounted on an arvor would it, I thought they were all shaft drive so the transducer would be aft of the prop? Obviously that doesn't apply if it does have an outboard.
Personally, I'd be tempted to try just placing it in a Plasticine well with oil, and then dangle it over the side to give a comparison when anchored over some sort of feature.
If the poster does end up doing that, I'd love to see some screen shots of the comparison. What I find is that there's a line of interference at the top of the screen, but that's easily tuned out by playing with the settings. Other than that, I don't know what other details gets lost with firing through the hull and being based over mud, there's not a great deal to see on downvision around these parts!

Anyway, glad you got yours resolved, and I'm sure it is going to give you better resolution through the properly mounted transducer.
 
Yes they are shaft driven so as I said it would need to be mounted in the hull using one of the various plasticine, oil bath, putty, blue tack, epoxy etc solutions, as you say murv it could not be mounted on the transom as the interference from the prop would give you a mush reading, sorry if I didn't make that clear in my answer to the post.

I can't comment on clarity of thro hull over in hull as neither worked! We have loads of rocks and wrecks so when I eventually get mine back form Raymarine I'm rather hoping the clarity is excellent but whether it would have been any worse with a in hull transducer I'll never know.
 
Having just launched, for the first time I have been able to check out my new Garmin Striker fishfinder that I installed over the winter. Having read the suggestion by the manufacturer that I should check the best position using a plastic bag filled with water, I decided that I wouldn't faff about with complicated oils or epoxying the transducer. Instead, I cut the bottom out of a margarine tub and stuck it to the inside of the hull using sikaflex. Then I added water and popped the transducer in. It seems to work fine - picking up the mud less than a meter down in my berth and also 65 metres down under the Forth Road Bridge. I even saw a fish!
This is the second time I have replaced a Raymarine echo sounder with a much cheaper fish finder with the transducer fixed internally. The first time was on a Westerly Riviera which has a hull built like the proverbial brick outhouse and gave accurate depths over 100 metres. The Hunter is rather lighter but seems fine.
 
I have now had a response from Raymarine saying there is nothing wrong with the unit. As I waited (on their advice) for 10 months with a non functioning unit, until the boat came out of the water to fit the through hull transducer, by the time it went back in, the 12 month warranty was 2 weeks over. I await to see if they are going to charge me for telling me that the unit (allegedly) has nothing wrong with it. Although I've had the unit for over 12 months it would be fine if I never went deeper than 10m. The whole setup has now cost me in excess of £500 and regret is the word I'm looking for. I still don't understand how they can claim the unit is fine when it has worked fine until 10m then the lost the depth and the picture turned to mush. The 2 pictures attached (I hope) were taken stationary at 20m with a through hull professionally fitted transducer, you decide.

IMG_20170302_115422698[1].jpgIMG_20170302_115329985[2] (640x360).jpg
 
i know this post originated a while back but i noticed there has been some recent comments on the subject.
I have just recently purchased a boat and plan to buy the Dragonfly 4 PRO Combo and fit within the next month.
I like others in the post don't want to fit the transom mounted transducer as my birth is tidal and boat sits in soft mud when tide is out and suspect problems if fitting to transom.
I planned to fit the transom mounted transducer in hull using either epoxy or one of the other methods described.
a couple of questions i have
- when mounting in the hull where have people experienced the best results Aft center or in the middle of boat middle of hull
- my thoughts were centre to reduce pitch issues but not sure aft ,mid or fwd
- when i read about putting in oil am i correct in saying build a dam pour in oil and Mount transducer so it is siting within oil bath ? if so what type of oil would you's recommend
 
I too have had total success mounting a transom mount tranducer inside a hull on 3 different boats. The first I followed the wisdom of the time, 20 years ago and fitted it in a tube of castor (?) oil the following two boats I just used a bit of gelcoat filler on one and on the other i used epoxy. Both worked perfectly but I would not go down the epoxy route as when I came to remove the transducer it brought away a bit of the layup with it. So a rigid adhesive but not too good a bond! As has been mentioned Sikaflex is also good.
 
gordiew said:
does the whole transducer need to be in the adhesive or only kind of wiggled into it so bottom section is in it
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I identify the best location, as far forward as possible, by putting the transducer in a poly bag with some water and moving it around the hull.
Then I just put a big dod of silicone sealant (cheap bathroom stuff) on the face of the transducer and place it in position trying to avoid air bubbles.

Only needs to be the face of the transducer and typically lasts at least five years before needing replaced.
Takes five minutes and costs a few pence.
 
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