Direct to Hull Mounting Stainless Transducer Bracket - Corrosion?

[SoCalAngler]

I am preparing to install a Lowrance 3 in 1 AI transducer on my new Tracker. Hull is painted aluminum.

Reading install instructions from Lowrance, it suggests using a plastic isolating material such as "King Starboard" to prevent corrosion between Alum hull and SS bracket (dissimilar metals).

I was planning on installing SS bracket directly to hull, as I want to use the existing two holes from previous transducer.

However, after reading install instructions, perhaps I should use a piece of King Starboard (HDPE) and screw it into hull using the two existing holes and attach transducer bracket to HDPE. OR... How about a thin piece of rubber between bracket and hull?

Thoughts?

[javjoe]

I used a star board block using the existing holes from the factory installed transducer.

[CincyGus]

I used a star board block using the existing holes from the factory installed transducer.

Exactly. Buy a piece of Starboard, Pre drill a couple holes in it where you want the mount to sit. Put a bead of 5200 a inch inside the edge and in the holes in the hull along with on the back side of the starboard holes. You will the old transducer holes, the new holes for mounting the star board and never have to put another hole in your boat for transducers.

[Real L]

Exactly. Buy a piece of Starboard, Pre drill a couple holes in it where you want the mount to sit. Put a bead of 5200 a inch inside the edge and in the holes in the hull along with on the back side of the starboard holes. You will the old transducer holes, the new holes for mounting the star board and never have to put another hole in your boat for transducers.

This...

and you will get better performance from your transducer with a piece of starboard. It puts the transducer a little farther away from the hull in a better flow of water if the 3 in 1 is for sounding at speed.

[Fireball]

I never had corrosion with direct contact from MANY Lowrence transducer installations on many different aluminum boats. But these boats never touched salt water.

[alanhore]

So are the screws aluminum? If not why wont the screws also corrode the hull.