Mounting transducer with no screws in the hull

[SeanT]

Hi all

I did some searching and couldn't find a direct answer to my question. I'm wondering if there's a way to install a transom mount tranducer without actually screwing into my hull. I'd just rather not, all things considered.

One idea I'm considering is mounting a hockey puck (sort of like the SternMate idea) to my transom using JB Weld or 3M 5200. Then screwing the transom mount to the hockey puck. I could also use a chunk of thick plastic or plexiglass or something.

Would 5200 or some other kind of marine epoxy hold it solid to the transom? The boat I want to mount this on is a direct drive ski boat, and the bottom is fairly flat at the transom.

Or do I just suck it up and drill?

 

[ezmobee]

Re: Mounting transducer with no screws in the hull

I think 5200ing something to your hull and mounting the transducer to that is an excellent idea.

 

[dingbat]

Re: Mounting transducer with no screws in the hull

http://forums.iboats.com/showthread.php?t=234916&highlight=transducer+mounting+plate

 

[salty87]

Re: Mounting transducer with no screws in the hull

get a shoot thru hull and epoxy it to the inside of the hull bottom

 

[Lion hunter]

Re: Mounting transducer with no screws in the hull

Go to the makers site and they will have instructions for mounting a through hull transducer. Most say to use epoxy but I think 5200 would work great.

 

[SeanT]

Re: Mounting transducer with no screws in the hull

http://forums.iboats.com/showthread.php?t=234916&highlight=transducer+mounting+plate

Thank you - that's actually the thread I was looking for - I knew I wasn't dreaming. "plate" was the magic word I hadn't tried yet.


Thanks for the through hull suggestions, but I'm not going there. All I want is depth and temperature on my transom mount, and I don't care if the picture is scrambled at high speeds. I just want to know how deep the water is when puttering about so I can learn a little something about where not to go in lakes. Granted, being at the back of the boat is a little counter intuitive on that, but I can work with it.

I'm going to hunt down some plastic or teak. Failing those, I'll use a hockey puck.

 

[SeanT]

Re: Mounting transducer with no screws in the hull

Oh - I thought shoot-through hull was a different transducer. Yes, I see what you guys mean now.

I'd lose temperature though, which kind of stinks.

So, I could just glue the transducer to the bottom of my bilge, basically where the bilge pump is, right?

 

[high'n'dry]

Re: Mounting transducer with no screws in the hull

Or mount a piece of Starboard to the transom with two screws. Then install the transducer to it. If you ever need to replace the Starboard then just match drill it from the old piece so it always uses the original mounting screws.

 

[SeanT]

Re: Mounting transducer with no screws in the hull

Yup - I guess what I'm trying to figure out is if 3M 5200 will hold something firmly to the hull with no screws at all. So far from what I'm hearing its a solid maybe, so I think I'll try it. Worst case I'll lose a transducer (the way the cable will run, it won't hit anyone if it flies up).

 

[salty87]

Re: Mounting transducer with no screws in the hull

So, I could just glue the transducer to the bottom of my bilge, basically where the bilge pump is, right?

if your bilge pump is toward the back. my bilge pump is in front of the engine (direct drive). you do lose temp though...i stick my hand over the side to check water temp.

if you mount to the transom and don't want to drill, you'll have a wire running over the transom...not great for swim platform activity

 

[SeanT]

Re: Mounting transducer with no screws in the hull

if your bilge pump is toward the back. my bilge pump is in front of the engine (direct drive). you do lose temp though...i stick my hand over the side to check water temp.

if you mount to the transom and don't want to drill, you'll have a wire running over the transom...not great for swim platform activity

Yes my bilge is in front of the engine as well.

Actually, my vent is in the top of the transom, so I was going to route the cable up, behind the platform (there's a gap), and into the vent, where it gets inside the hull and where all the cabling goes. I think it will work well if I go with transom mount.

 

[4JawChuck]

Re: Mounting transducer with no screws in the hull

You can buy plastic boards to mount transducers etc., one mfg is Rig Rite.

http://www.google.ca/search?hl=en&q=rig+rite+mounting+board&meta=

Judging by how strong the 5200 cured in the holes I sealed I would say that board glued solid on a transom would be pretty strong, as long as the 5200 was allowed to cure properly...it seems to harden up over a few weeks. I would still screw it on though, whats the harm? The board will be permanent so you screw things to it instead of into the transom? Just make sure to goop the two mount screws and your good to go for the life of the boat.

 

[captharv]

Re: Mounting transducer with no screws in the hull

If you don't want to drill holes in the transom, buy a piece of starboard or equivalent. Cut a piece about 3" X 6" and glue it to the hull where you intend to mount the 'ducer. Then screw into that.
However, I was a marine electronic tech some years ago and installed 100s of transom mount and thru-hull (not glue in but drill a 1" hole thru the hull bottom) and had no complaints of leaks.
My personal boat has a 'ducer mounted on the stern and works fine. Shows fish in 100' of water at 25 knots.
The key is locating the spot (read the instruction manual), then drill the holes, using a template or the actual mount to locate the holes. I use a 5/32" drill and #10 hardware.
Then, use a 1/4" drill turning backwards as a countersink, so when you put in the screw it won't crack the gelcoat. For final assembly, I use 4200 fast set. use it liberally, and some denatured alcohol for clean up of the excess. That's how its supposed to be mounted.
The glue installation may or may not work. Sometimes you have to move the ducer because of an air void or hull coring. When in the business we would not glue in ducers because the high end fish finders/chart recorders would not show fish properly. However, the stuff being made these days have microprocessors and you have a better chance of working the first try, but no guarantee......

 

[Capt'n Chris]

Re: Mounting transducer with no screws in the hull

Re: King Starboard statement adhering their product

"StarBoard can not be glued using standard adhesives. Products like 3M's 5200 work well as a water sealing caulk but will not adhere StarBoard to itself or other materials in a permanent bond".

 

[Lion hunter]

Re: Mounting transducer with no screws in the hull

In the end it seems like a lot of extra work to avoid a couple screw holes. Properly installed they will never leak or cause an issue. I alsways figured that as many holes that are through the hull anyway what's a few more. It can be kinda hard to get 5200 in the holes so I just coat the screw threads with it and screw them in.

 

[Moody Blue]

Re: Mounting transducer with no screws in the hull

With the right materials, the 3M 5200 will very securely fasten your transducer to the transom. Contrary to what many believe, 5200 does not bond well to stainless steel or aluminum. Do some research and you will find out what I mean.

I have used 5200 to bond a plastic bodied speed wheel to a fiberglass hull with amazing results. After several years I needed to remove it to install trim tabs and I actually de-laminated the gel coat from the fiberglass in trying to get it off. Be sure to let the 5200 fully cure (7 days +).

 

[SeanT]

Re: Mounting transducer with no screws in the hull

Thanks for all the good ideas guys. I guess I mainly don't want to put holes in my baby, but I see now that I might be worrying too much. I guess I'm also not particularly confident about transducer placement, being a ski boat and not a typical V hull, so I may need to move it.

Due to the 7 day or so curing time of 5200, I probably won't actually perform the installation until the end of the month anyway, I'm using the boat almost daily right now trying to squeeze in some more summer.

Thanks for all the good ideas - I'll post back here with how I eventually do the installation.

Also, just to clarify for a few people - I never at any point thought I could 5200 the metal transducer bracket straight to the transom - I would use screws for that, in case I need to fine tune the position. My hope was to use 5200 ONLY to install a transom plate.

 

[SeanT]

Re: Mounting transducer with no screws in the hull

Quick question guys - I got amibitious today and mounted my finder on my dash. I wired it in temporarily and turned it on just to play with it. I haven't bothered completing the install yet because screws or no, I'll be using 5200 to seal them and it takes a week to cure, and I'm in the water lots right now.

Anyway, the depth readings were completely out to lunch, even when I submerged it and held it level in a bucket of water. It's an Eagle Cuda 300 (just a cheap one, I know). Is this normal? Will it only work when properly mounted and submerged in a lake?

My last boat had a Humminbird 525 (installed by PO) and when out of the water it would give me the air temperature and distance to the driveway...

 

[4JawChuck]

Re: Mounting transducer with no screws in the hull

A bucket reflects the sound from sides and bottom causing all kinds of noise and standing waves, basically...it won't work in a bucket.

 

[SeanT]

Re: Mounting transducer with no screws in the hull

Hah okay - and I guess dangling in the air reflections from objects nearby would be causing all sorts of noise too.