UHMW to mount transducers to stern?

[bigdogg1]

I just picked up a small section of UHMW to use as a mount for my transducers and to cover up an ugly screw pattern. I was going to use Starboard but I was offered a better deal and a thicker piece (happier to tap in a longer screw to the UHMW).

I haven't used the product before but was told that it would be fine below the waterline. I went down a bit of a rabbithole and read that the material absorbs water...?

Has anyone used this below the waterline with success or failure?

 

[zurk]

starboard is HDPE and UHMW is used for jetboat bottoms so it should be fine.

Property	HDPE	UHMW
Melting Point (°C)	118-137	133
Density (g/cm3)	0.93-0.97	0.93-0.95
Hardness (Shore D)	50-76	> 63
Tensile Strength, Yield (MPa)	11-43	20
Tensile Elongation (@ 73°F, %)	600	350
Water Absorption (%)	0.010-0.10	0.010
Chemical Resistance	Good	Good
Heat Deflection Temperature at 0.46 MPa (66 psi) (°C)	42.8-93.3	65
Abrasion and Wear Resistance	Good	Good

 

[bigdogg1]

 

[Marley]

I used a plastic cutting board. It has been on there for a few years with no issue

 

[brutus]

Be careful with that stuff, caulking don’t stick to it,so your are covering screw holes thinking calking will seal it, not happening , don’t believe me lol, put some on it let it cure and then see if it sticks

 

[Marley]

Be careful with that stuff, caulking don’t stick to it,so your are covering screw holes thinking calking will seal it, not happening , don’t believe me lol, put some on it let it cure and then see if it sticks

I should have been more clear. I mounted the piece of cutting board with 4 screws and sealed the holes. The two transducers are mounted to the board and I have been able to move them around to get the best return without worrying about putting a bunch of holes in the transom.

 

[brutus]

I should have been more clear. I mounted the piece of cutting board with 4 screws and sealed the holes. The two transducers are mounted to the board and I have been able to move them around to get the best return without worrying about putting a bunch of holes in the transom.

All I am saying is if you covered the screw holes behind the piece assuming you caulk the back before you screwed it in ??? No no, caulking does not stick to that s….

 

[bigdogg1]

Really happy withe the final install. Exact setup as brutus and being 1" thick, I am 'confident' the transducer screws will have a good bite. Lots of sikaflex around perimeter, middle, and 4 x mounting bolts. Stuff was much easier to work with than I had been told. Table saw, belt sander and router produced a nice final product.

 

[Rayvon]

As Brutus says caulking doesn't stick well to starboard,but you can make a pretty good mechanical connection by cutting 45 degree saw cuts in the back side filled with Sikaflex or 5200. Cutting board material isn't UV protected but will still last a while underwater. I've done lots of them.

 

[Captain PartyMarty]

I used Gflex Expoy to mount starboard to my transom been on there for 5 years now and is still rock solid!