Transducer mount - stern saver

[tbeatm]

For those boat owners that also did not want to drill holes into the transom and use HDPE or starboard to mount your transducer; I used a piece of King Starboard and almost lost my transducer running out to Fairfax on Friday.

I sanded the piece and notched grooves in it for the sikaflex to hold. Worked for almost 2 years and popped off. Adhered to the transom quite well, but not a lick of it to be found on the piece of King Starboard. Should I just use normal cutting board or something else to mount the transducer to? As I understand, its pretty rare for this to happen. No damage to the transducer or its mount thankfully.

 

[Saxe Point]

I tried this on my previous boat. I did a ton of research and it’s pretty clear that getting any kind of plastic to reliably stick to fibreglass is a very difficult thing. So what I did is, I screwed the plastic (I think it was starboard, but it could’ve been something else) into the hull, making sure that the screws were properly bedded in Sikaflex to prevent water intrusion into the transom. That way I could move the transducer around on the plastic itself. It worked well.

I decided it was not worth the trouble on my new boat. I just measured everything up and screwed the transducer into the transom, again making sure that the holes and screws were properly bedded in Sikaflex. I don’t really move the transducer around anyway. I also read that people worry way too much about piercing the transom for a transducer. If it’s done properly, no water is going to get in there.

 

[Sandpiper]

I read on thehull truth to use plastic baseboard that they install in bathrooms. Seems to work well

 

[Sharphooks]

The Stern Saver product with 3M backing seems to hold long term as long as you properly prepare the mounting surface

I always sanded off the bottom paint, and wiped with alcohol and never had one come loose

Not sure I’d hang a 1 kw monster sized transducer off one but the smaller skimmer transducers will stay put

I have two I’m not using… if interested PM for details

 

[tbeatm]

I tried this on my previous boat. I did a ton of research and it’s pretty clear that getting any kind of plastic to reliably stick to fibreglass is a very difficult thing. So what I did is, I screwed the plastic (I think it was starboard, but it could’ve been something else) into the hull, making sure that the screws were properly bedded in Sikaflex to prevent water intrusion into the transom. That way I could move the transducer around on the plastic itself. It worked well.

I decided it was not worth the trouble on my new boat. I just measured everything up and screwed the transducer into the transom, again making sure that the holes and screws were properly bedded in Sikaflex. I don’t really move the transducer around anyway. I also read that people worry way too much about piercing the transom for a transducer. If it’s done properly, no water is going to get in there.

That makes sense, I like the freedom of moving it around if needed, or space to add a second one for other purposes. Might go this route but will still look at other options. Thanks for the info!

 

[tbeatm]

The Stern Saver product with 3M backing seems to hold long term as long as you properly prepare the mounting surface

I always sanded off the bottom paint, and wiped with alcohol and never had one come loose

Not sure I’d hang a 1 kw monster sized transducer off one but the smaller skimmer transducers will stay put

I have two I’m not using… if interested PM for details

These seem to be hard to get in Canada from what I remember when I was originally looking. I'll send you a PM since it would be great to talk to someone who has used it before. Thanks.

 

[23Hourston]

You got a bevel those grooves. V shaped kind of

 

[Captain PartyMarty]

My block of Starboard that I glued on with West System G Flex has been on the boat for the last 3 years and is still rock solid! Use a better glue and it will stay on there

 

[Corey_lax]

Need more grooves in it. More grooves = most surface area for the adhesive to bond to. I can’t remember if I used sika, 4200, or 5200 but it’s been solid for 4 years or so.

 

[Flashman]

You're going to struggle to get an adhesive to bond to HDPE. Surface area is only going to get you so far. If you really want to user starboard, I would drill a bunch of holes in it (1/4" minimum) counter sink them deep on the side you attach the transducer. After you glue the block to the transom, before it cures, fill all the counter sunk holes with the same adhesive making sure the adhesive fully fills the holes and is continuous through to the adhesive on the transom. This forms mechanical anchor points, essentially dovetails, that require the adhesive to be torn apart for the block to come off. This doesn't rely on more surface area of a very poor bond as the grooves method does.

If you get a different material, piece of aluminum, fiberglass, stainless you'll be miles ahead getting a good bond. Just requires drilling and tapping holes. Fiberglass and aluminum tap really easily.

 

[Rayvon]

" Flashman" has some good idea's,I like the fiberglass idea better than aluminum though because of corrosion.I've done lots of them with starboard by cutting grooves with my table saw @ 45 degrees.No failures that I know of,I use Sikaflex.

 

[tbeatm]

You're going to struggle to get an adhesive to bond to HDPE. Surface area is only going to get you so far. If you really want to user starboard, I would drill a bunch of holes in it (1/4" minimum) counter sink them deep on the side you attach the transducer. After you glue the block to the transom, before it cures, fill all the counter sunk holes with the same adhesive making sure the adhesive fully fills the holes and is continuous through to the adhesive on the transom. This forms mechanical anchor points, essentially dovetails, that require the adhesive to be torn apart for the block to come off. This doesn't rely on more surface area of a very poor bond as the grooves method does.

If you get a different material, piece of aluminum, fiberglass, stainless you'll be miles ahead getting a good bond. Just requires drilling and tapping holes. Fiberglass and aluminum tap really easily.

Yeah I really like that idea about the counter sunk holes. Thanks for the info and tips. I have a piece back on there now since I went fishing the last couple of days. Holding strong, I put a lot more cuts at 45 and pretty thick on the outside perimeter as well. I think long term I would go with the fiberglass piece.

 

[Rayvon]

Yeah I really like that idea about the counter sunk holes. Thanks for the info and tips. I have a piece back on there now since I went fishing the last couple of days. Holding strong, I put a lot more cuts at 45 and pretty thick on the outside perimeter as well. I think long term I would go with the fiberglass piece.

Let me know if you want me to lay up some fiberglass,I've been doing a lot of it lately.

 

[Unreel]

I put 2 screws in mine and sealed it up with 5200.

 

[Bifmalibu]

I would use a piece of Azek material. It bonds well to glue and is paintable to fend off the UV light. It is also available in 1x and 2x4 thickness if you want more screw penetration.

 

[tbeatm]

Let me know if you want me to lay up some fiberglass,I've been doing a lot of it lately.

Thanks Ray, that might be the long term play. Could potentially make two so I can take the old transducer off that came with the boat on the port side and plug those screw holes, and allow a spot for a second one in the future.

 

[littlechucky]

I bought the “stern saver” product 3 yrs ago. Still holding strong. I believe I got it off eBay from the US. Overpaid for what they sell for, but was hard to find…had to pay shipping and FX.