Why Di-Electric Grease on a Boat?

What the heck is di-electric grease and why, when our can of CRC Di-Electric Grease was empty, was it such an emergency?  We walked all over Placencia Belize, poking our heads into any little shop that might have anything remotely related to grease, only to find out there is no di-electric grease anywhere in town.  David even went so far as to add it to the list of requests for a guest flying down from the US.  Such a big deal about grease?

Corroded Windlass Switch the Culprit!

Corroded Windlass Switch the Culprit!

If you look up the definition, di-electric grease is a non-conductive silicone grease designed to seal out moisture, thus eliminating corrosion – always a good thing on a boat!.  It protects wiring and electrical connections from salt, dirt and corrosion.  Non-conductive means it doesn’t enhance the flow of electricity.

It’s valuable anywhere there’s the potential for moisture to intrude, which on a boat could be just about anyplace.  We tend to use it mostly for electrical connections “outside” the living quarters, in the chain locker/sail locker, in the cockpit lazarettes, on deck, on the arch, etc., but it can also be good to extend the life of interior light sockets, or so they say, we don’t know if ours are “extended” or not, but they still work!

It doesn’t need to be CRC, there are different brands. There seem to be dozens of uses, but all get back to protecting any exposed wiring from salt air or water.   Beware that over a long period of time, dielectric grease may deteriorate silicone rubber such as o-rings, so don’t use it on anything with silicone rubber.  Other than that… anytime we clean corrosion off anything that could possibly be exposed to salt air,  we put a thin coat of di-electric grease on when we put it back together to protect it from corrosion, examples include:

Windlass Switch Being Cleaned

Windlass Switch Being Cleaned

1.  Battery posts/terminals

2.  GPS Electrical Connection in Cockpit

3. Outboard: coat spark plug connections

4.  Bow Navigation Lights

5.  Mast Navigation Lights

6.  Deck Lights on Mast

7. Cockpit Speaker Wire Connections

8.  Windlass Heavy Duty Battery Switches

Clean vs Corroded Windlass Cables

Clean vs Corroded WIndlass Cables

9.  Diesel Ignition Switch

10.  Alternator Electrical Connections

11.  Starter Electrical Connections

12.  RPM tachometer connection

13.  Wheel Autopilot Wire Connections

14.  Hydraulic Autopilot Wire Connections

15.  Up Down Deck Buttons Electrical Connections for the Windlass

16.  SSB Radio Connection to the Backstay Antenna

(then sealed with liquid   electrical tape)

Di-Electric Grease Applied to Protect From Corrosion ... Until Next Time!

Di-Electric Grease Applied to Protect From Corrosion ... Until Next Time!

17.  Interior Light Sockets

18.  VHF Remote Cockpit Plug In Electrical Connection

19.  KISS Wind Generator Wire On Off Switch in Cockpit

20.  Solar Panel Plugs Connecting at Panels Outside

In short, any electrical connection that has the potential to come into contact with salty air or water can usually benefit from a dab of di-electric grease.  Add di-electric grease to your regular routine when you put something back together and see if it works for you!


If you have other uses for di-electric grease on your boat, please leave a comment and share the information!  THX!  Jan



  1. Silicone Grease is third generation and one of the most advanced lubricating products made of silicone oils scientifically known as Poly diamethyl Siloxane with amorphous silica as binding material. Silicone Greases are highly stable greases under extreme pressures and temperatures.
    Thanks fr the good post

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