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Water Wicking Wire Corrosion




Water wicking is not when you stop half way to Catalina for a brief intermission. What it is and how it affects the electronic gear on your boat should be of concern to you if you want to keep your electronics in tip top shape.

If you have ever stripped back a wire on your boat to reconnect a faulty connection, say to one of your Kodiak Bait Pumps and found that the wire was black or worse yet non existent, then you stripped it back further to only find it still black, you have water wicking.

Water wicking is caused when water enters the connection where two wires are connected or if a crack in the wire exists. Bait Pumps are very prone to water wicking for the following reasons. After your pump has been running for several hours the motor in the pump gets hot and the air that is in the pump expands. When the pump is shut off, the air that is in the pump cools, thus causing some what of a vacuum. Any water that is present at the splice where the pump connects to the boats wiring is sucked up the wire toward the pump motor, like the wick of a oil lamp wicks the fuel to the end that is lit. After time or through repeated applications of heating and cooling (normal usage) the water will eventually be sucked into the motor housing and cause failure. The shorter the length of wire from the pump, the amount of water exposure, how well sealed the unit is and the heat produced by the unit will affect the severity of the water wicking.

If you are one of those boaters that cuts off five feet of the six feet of wire that we put on our pumps because you have other uses for it, and makes all connections with electrical tape and your connections get wet, you probably know what salt water damaged wire looks like. The good news is bait pumps are cheap and they come with five extra feet of tin coated wire. But other electrical items on your boat such as trim tab pump motors, auto pilot tiller transducers, main tank oil injection pumps, etc are not and these units are normally found in very wet areas of your boat.

The solution: If the manufacture puts extra wire length on the unit, don’t cut it off. The longer the wire, the longer it will take for water to travel up it. Use water proof butt connectors at all wire joints. These are the type that you crimp then shrink with a heat gun. If you are a purest, you will go one step further and seal the water proof connectors with shrink tubing, I double seal every thing. Make all connections as far away from the bilge area as possible. Buy silicone spray by the case and use it wherever there is the slightest chance of water intrusion, I use Yamaha and feel it is the best buy only marine grade tin coated connectors and wire, the insulation on the wire is much thicker and less prone to cracking that commercial grades. The shrink tubing that is available at Radio Shack won’t stand-up to the environment and will crack, buy the thick walled marine grade manufactured by Anchor, it also has a glue in it that melts and further seals when heated, it is available in most marine stores. Try and keep fuse holders and circuit breakers out of the bilge area. I have tried them all and have not found any that are 100% water proof, unless you seal them with shrink tubing which is redundant. Liquid Tape is better than real tape but will eventually crack and allow water into the joint, use it only when there is no alternative.

Water proof shrink connectors are a must and the way they are installed is equally important. Crimping must be done with the proper tools or you will tear or crack the insulation. Do not use vise grips or the pliers type crimping tools sold at hardware stores. Purchase a ratchet type crimping tool they are sold at most first class electronic stores or your marine dealer can order you a set made by Anchor part #702017, they do not over crimp the connector and have round jaws so not to tear the installation. While you are at it, purchase a set of top quality wire strippers, the pliers types that have two hardened steel jaws with various wire gauge cutters ground in the jaws. To shrink the insulation on the connectors or to shrink tubing you will need a heat gun such as the type Black and Decker makes. Don’t use a lighter as you will cook the insulation and maybe blow your self and your boat up.

Another hint on using water proof connectors and shrink connectors. There will be times when you want to connect #22 wire to #14. If you put the #22 wire into a #14 butt connector, the shrink tubing will not shrink down enough to seal the #22 wire. The solution is get #22 shrink tubing and cut two or three lengths about 3/4" long. Strip off some of the insulation that is to be crimped in the butt connector then slide on a 3/4" length of shrink tubing past the bare wire and shrink it, slide on another piece of shrink tubing and do the same. After two or three lengths you will have built up the diameter of the #22 wire to the same size as the #14 wire and now you can shrink the butt connector to the #22 gauge built up wire. The ABYC does not recommend soldering wire ends as they can fatigue and crack from vibration, use your own judgment.

Larry E. Wikin
Kodiak Marine, December 1994
December, 1994



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