through hull transucers vs mounted_moored Fibreglass boat

[Plumb]

Hey all, I'm not far off getting my feet back onto a boat, if it comes off ( inspections pending) will be a fiberglass hull (solid) so I'm eagerly looking into sounder and chart options. I'm leaning towards the Lowrance HDS – 9 live combo https://www.lowrance.com/en-au/lowrance/type/fishfinders-chartplotters/hds-9-live-ausnz-noxd  and wanted Total scan through hull transducer https://www.lowrance.com/en-sg/lowrance/type/sonar-transducers/totalscan-mh-thru-hull/ however with the fairing block the transducer can only accommodate to dead rises of 5 degrees max. which if im correct in assuming is basically a flat bottom boat...so i may just run with a standard active image transducer.

 

that being said are there any issue with mooring a transducer? assuming it was wiped clean from time to time. I'd really like a through hull but without drilling the hull ( which i don't want to do) I cant thing there an option?? iv heard that some transducer will still work through the fibreglass? ll give that a go in a temporary install, but failing it working are there any other options in a decent combo through Hull? id happily go separate units but with a 9" display i don't really see the need.

 

oh its a slow old boat, so scanning while under way wont be an issue, id just prefer the transducer not in the water 24/7

 

Cheers Luke 

[PaddyT]

ive got a through hull in my tinnie, and the total scan. however its a trailer boat, the set up is fantastic. Call Lowrance and im sure they will give you the run down for a moored boat.

[Plumb]

2 minutes ago, PaddyT said:

ive got a through hull in my tinnie, and the total scan. however its a trailer boat, the set up is fantastic. Call Lowrance and im sure they will give you the run down for a moored boat.

spoken via email, im just concerned with the dead rise of 5d, thats pretty flat.....

[rickmarlin62]

Try setting your transducer up on a slide rail    lift out of water when moored  slide down and lock into place when you want to use it    we had this setup on moored 23ft sharkcat  easy

[zmk1962]

10 hours ago, Plumb said:

 iv heard that some transducer will still work through the fibreglass? ll give that a go in a temporary install

I have an Eagle (which is LEI) High-performance, low-profile 50/200 kHz Skimmer® dual-frequency transducer with built-in temp sensor. I have this transducer permanently fitted with epoxy as a shoot through hull mount which reads bottom at depths past 500m and speeds above 60kmh. It is fitted in my fg boat with no drilling of the hull.

It's not so much the transducer but the manufacture of the hull that determines if you can shoot through. If the hull and the transducer mounting compound is solid fglass (epoxy), it has the same transmission as water, so no problems. If there is any wood, or air bubbles in the hull or if you try to use silicon in between the transducer and hull, it will absorb the transducer ping signal and it wont work. 

The best way to test, is to place your transducer inside the hull where you think it should best be, fill some water around it to remove any air bubbles (you may need to build a small wall out of something like plasticine to keep the water around the transducer), then place a wet sand bag ontop of the transducer to keep it in place as you go for a test ride. You may need to try several places to test and find your best transducer/hull location. 

Once you have settled on the ideal location and you are ready for the transducer fitting you can use extra eopxy on one side of the transducer to correct the 5deg hull slant. Just make sure there are NO bubbles trapped in the epoxy inbetween the transducer and hull.

The above worked for my transducer - you can contact Lowrance tech support and have a chat on this topic  

Cheers Zoran

Edited August 5, 2020 by zmk1962

[Plumb]

11 hours ago, rickmarlin62 said:

Try setting your transducer up on a slide rail    lift out of water when moored  slide down and lock into place when you want to use it    we had this setup on moored 23ft sharkcat  easy

Cheers, I had looked at this the boat is a really old school looking Cruser so I’m trying to avoid doing anything external, definitely might be the 2nd option tho

 

9 hours ago, zmk1962 said:

I have an Eagle (which is LEI) High-performance, low-profile 50/200 kHz Skimmer® dual-frequency transducer with built-in temp sensor. I have this transducer permanently fitted with epoxy as a shoot through hull mount which reads bottom at depths past 500m and speeds above 60kmh. It is fitted in my fg boat with no drilling of the hull.

It's not so much the transducer but the manufacture of the hull that determines if you can shoot through. If the hull and the transducer mounting compound is solid fglass (epoxy), it has the same transmission as water, so no problems. If there is any wood, or air bubbles in the hull or if you try to use silicon in between the transducer and hull, it will absorb the transducer ping signal and it wont work. 

The best way to test, is to place your transducer inside the hull where you think it should best be, fill some water around it to remove any air bubbles (you may need to build a small wall out of something like plasticine to keep the water around the transducer), then place a wet sand bag ontop of the transducer to keep it in place as you go for a test ride. You may need to try several places to test and find your best transducer/hull location. 

Once you have settled on the ideal location and you are ready for the transducer fitting you can use extra eopxy on one side of the transducer to correct the 5deg hull slant. Just make sure there are NO bubbles trapped in the epoxy inbetween the transducer and hull.

The above worked for my transducer - you can contact Lowrance tech support and have a chat on this topic  

Cheers Zoran

 Cheers Zoran, that’s great advice exactly what I was hoping to hear, I’ve watched all the YouTube clips installing the transducer in resin, but hadn’t thought how to test it. It’s solid fibreglass so fingers cross the testing is productive. 

[zmk1962]

You have two good options to pursue. The downside to epoxy permanent fix approach is it’s much more complicated to upgrade or change. I now have a great 1kw 50/200kHz transducer but its plug fitting is not compatible with new head Units. It’s a real pita to chisel it out from the tight space where it’s fitted - but I’ve done it once before when I replaced the old hummingbird so I know it’s possible. 
Anyway while the system works it’s staying put. 
cheers Zoran 

[TK01]

I've wondered about this issue too.  Is it possible to mount it right on the keel?  I'd be very worried about hitting it on something but curious if it can be done that way.

[Plumb]

Anyhow im going to install the supplied transducer, as suggested I’ll try a few locations on the hull by Testing the location submerged in water.

while slipping the boat I’ve located a few spots with minimal dead rise. Once a good location is found I’ll install it in resin.

 

Edited August 9, 2020 by mrsswordfisherman
THREAD RESTORED AND LAST POST MERGED

[zmk1962]

You have a lot of boat structure under the hull, and the prop is set back from the stern - just bear in mind these structures and any turbulence created by the prop  will affect your sonar operation.  Ideally you want a location that has smooth (laminar) water flow so be prepared to test spots further toward the bow. Alternatively, I see two planing planks (fixed trim tabs) at the stern. They may well be good locations to mount your transducer.

Cheers Zoran

 

[Plumb]

1 minute ago, zmk1962 said:

You have a lot of boat structure under the hull, and the prop is set back from the stern - just bear in mind these structures and any turbulence created by the prop  will affect your sonar operation.  Ideally you want a location that has smooth (laminar) water flow so be prepared to test spots further toward the bow. Alternatively, I see two planing planks (fixed trim tabs) at the stern. They may well be good locations to mount your transducer.

Cheers Zoran

 

yer I'm looking at up front of the engine, left or right to avoid the keel and any prop distortion. the keel is timber glassed over, so wont transmit through very well if at all. The hull is full fiberglass.

Its not on a trailer ( pic's were taken during survey) and while I like swimming, I'm not keen on getting in in winter with my screwdriver  

[Plumb]

So I installed the standard transducer in the hull. To test it 1st, as suggested by Zoran, i just turned off the beige pump and filled it up. Seemed to work on in the marina so I pumped out out, cleaned, dried it and installed it on a bed of sicaflex, making sure there were no air bubbles. This way I figure if it has to be moved a Stanley knife and some time will be all that's needed, rather then epoxying it in straight away. I had a quick run on Sunday ( in the wind) and it seemed to work well. ill post up some pics of the install once I get back to a few other maintenance items, ( just forgot last time the floor was up) 

[zmk1962]

Sikaflex would be absorbing a lot of your signal. So it’s promising that it worked. 
cheers Z

[Plumb]

39 minutes ago, zmk1962 said:

Sikaflex would be absorbing a lot of your signal. So it’s promising that it worked. 
cheers Z

It hasn’t been tested at any great depth yet. I’ll let you know how it goes 

[Cladone]

I have a raymarine transom mounted transducer. I opted not to go thru hull. It lives in the water and never had any issues some 3yrs now. They also have mounting brackets so they can be slid up and wiped etc without lifting boat

[Plumb]

As the boats on a Port-a-slip while I do some upgrades, i think i might relocate the transducer to a standard external mounting. I haven't yet tested it at any great depth, but the structure  and side scan didn't really work as well as they should have...

Any thought's on replacement flooring? marine ply? i was thinking about something like seaboard https://www.allplastics.com.au/component/igallery/applications-menu/marine/seaboard?Itemid=741 but i cant seem to get a price of anyone. I want to insulate it a much as possible from the vibration and noise of the diesel engine. I was just going to replace the marine ply with new, but fixing sound proofing (foam backed left over from a recent job) to the under side. Then ill be sticking a detective imitation teak rubber flooring to the top side.