Boat Wiring Tips

[fragmeister]

Hi Raiders,

I recently had to fix a wiring issue in my 3 Year old Quintrex which, in my view should never happened and is a sad reflection on build quality.

The boat has a bilge pump with a field effect sensor (as opposed to a float sensor) which will sense when water is around the pump housing and switch the pump on to empty the bilge. The pump has three wires including a negative wire,  a positive wire switched form the boat dashboard and a permanent live positive directly from the battery switch though a fuse. Obviously. you want the pump to switch on automatically even if the boat is unattended or you are not aware that there is water in the bilge. It is definitely the case on my boat that you will get water in the bilge just through normal use.

I have an issue with the pump not coming on automatically and I found that the permanent live wire to the pump was in fact dead. I traced it to a crimped connection close to the bilge pump. This connector is the type that has a metal ferrule coated in plastic and you use crimping pliers to squash the connector on to the inserted wires. Not bad for cars but very average for boats and salt water.  A little salt water inside the connector and the corrosion will turn that crimped connection into an open circuit in no time at all. Pretty average really given how important your bilge pump is.

I cut the connector out and fixed it using this method which I would recommend for all electrical connections on your boat. You will need a pair of side cutters or wire strippers, a soldering iron, solder, a cigarette lighter or other source of heat and some heat shrink tubing.

1)  First strip the insulation for about 30 - 40 mm off the ends of the two cables to be joined as in the picture below. In preparation for the last step feed about 50 mm of heat-shrink tubing up one wire (about double the diameter of the wire should do it) but keep it well away from the joint so it doesn't shrink when you are soldering the wire.

 

2) Overlap the cables about half way along and twist them back on each other in opposite directions as in the picture below.

3) When its finished it should look like this.. except in focus!

4) Solder the wires together but first, a few tips on soldering. You can get a 100Watt Soldering iron from a major hardware chain for about $30. You need a powerful enough iron so it maintains it heat so don't mess around with smaller electronics soldering irons.

Heat the wire with soldering iron  so it is hot enough to melt solder touched anywhere along the wire. You can apply some solder the the point at which the soldering iron touches the wire to improve heat transfer but the wire should be hot enough to melt the solder if you want to achieve a good joint. It should flow into and along the wire if you get it right.

5) Once you have soldered the wire let it cool down for a few minutes and then slip the heat-shrink tubing back down over the joint and heat to shrink in place. See below.

What you now have is a strong and permanent connection as good as an unbroken wire.

This type of connected is called a Western Unions Splice and has been used in communications for more than a hundred years. It was used for joining telephone cables together in the field without soldering and the joint strength is high and connection resistance is very low. Soldering the joint and covering it with heat-shrink makes this the stand out method for joining cables in the marine environment.

I hope this helps anybody thinking of taking on a wiring job on their boat.

 

Cheers

 

Jim

 

 

Edited January 15, 2017 by fragmeister

[Wellzy94]

If you have a set of crimpers (or electrician's pliers) you can also use these cable links:

Just give them a wrap in electrical tape or cover with shrinkwrap.

Not as strong or as effective as solder, but a good alternative if you don't have access to soldering equipment!

[Fab1]

Can I advise that if possible use only marine grade tinned wire on your boat not plain copper wire.

Good post Jim .

[fragmeister]

13 hours ago, Fab1 said:

Can I advise that if possible use only marine grade tinned wire on your boat not plain copper wire.

Good post Jim .

Thanks Fabian... good point about the marine grade cable.

 

Cheers

Jim

[big Neil]

Thanks for the very descriptive, detailed explanation of the process Jim. Very east to follow, even for me. LOL BN

[fragmeister]

57 minutes ago, noelm said:

There is a guy in QLD that imports all sorts of marine connectors, they are the highest quality, and he does mail order in reasonable quantities, I think he calls himself Superior Terminals? Do a google it will find him, got lots of stuff off him over the years.

Thanks Noel,

I have used these in the past and they certainly are good quality. Interestingly, this is the type of connector used by Quintrex or the boat dealer but I still had to replace it to fix a corrosion issue.

Part of the problem is that these type of connectors must be used correctly and they rarely are. Good quality double crimping tools are recommended. Cheaper, single crimp tools can inadequately crimp the ferrule and the focus the crimping force on too narrow a point often weakening the wires inside the crimp. Additionally, they often cut the insulation exposing the connection to corrosion which was exactly what happened in my case.

Correctly done they are reliable but  I am not confident about them when they will be occasionally exposed to salt water and there is a better way that is reasonable simple.

If you are going to use crimped connections ( and I still do for certain applications) then I suggest you get a quality double crimper.

 

Cheers

 

Jim

 

 

[Fab1]

1 hour ago, fragmeister said:

Thanks Noel,

I have used these in the past and they certainly are good quality. Interestingly, this is the type of connector used by Quintrex or the boat dealer but I still had to replace it to fix a corrosion issue.

Part of the problem is that these type of connectors must be used correctly and they rarely are. Good quality double crimping tools are recommended. Cheaper, single crimp tools can inadequately crimp the ferrule and the focus the crimping force on too narrow a point often weakening the wires inside the crimp. Additionally, they often cut the insulation exposing the connection to corrosion which was exactly what happened in my case.

Correctly done they are reliable but  I am not confident about them when they will be occasionally exposed to salt water and there is a better way that is reasonable simple.

If you are going to use crimped connections ( and I still do for certain applications) then I suggest you get a quality double crimper.

 

Cheers

 

Jim

 

 

Another way to join two wires is to cleanly cut the ends of both wires and stick a pin half way in one wire then run a dab of quickset araldite or super glue around the tip of the insulation on both wires.

Then simply push the other wire over the remainder of the pin until both ends of the insulation meet.

done properly you would think its a single length of wire.

when I was a teenager this method drove me a couple of hundred Kay's after an alternator wiring failure and some.

As I always say,where there's a will there's a way.

 Cheers.

[raging]

On 16 January 2017 at 5:40 AM, MV Sunray said:

These are the crimps your after. Crimp first then heat activates the glue which melts the heat shrink to glue a totally water proof connection. Fastest and best connection cheers.

I use these, but also cover with an extra heat shrink tube. Not sure it makes a difference, just an attempt to keep water out

[Fab1]

36 minutes ago, raging said:

I use these, but also cover with an extra heat shrink tube. Not sure it makes a difference, just an attempt to keep water out

Another way is cut a small length of tubing or hose like vacuum line etc and feed this on the wire then solder,heat shrink and place tubing or hose over the lot and pump sikaflex sealant in one end until it comes out the other.

[Trailcraft43]

I always do mine like fragmeister.

Twist, solder and shrink wrap. 

Lasts forever.

Best way to go.

as crimps, etc always seem to corrode unless petrolium jelly is pasted around crimps.

Before elec taped up.

Edited January 20, 2017 by Trailcraft43

[Swampgecko]

On 16/01/2017 at 5:40 AM, MV Sunray said:

These are the crimps your after. Crimp first then heat activates the glue which melts the heat shrink to glue a totally water proof connection. Fastest and best connection cheers.

Those splice connectors are similar to what is used in the aviation industry, however they are not environmental splices. The military grade ones that we use at work have a small band of adhesive at each end. When hit with either a normal heat gun or infrared heat gun, the insulation sleeve shrinks and the adhesive bonds to the insulation of the wire giving the full environmental protection. When rewiring my boat in the last few weeks, I did all my connections by the the tried and true method of solder splicing and covering with heat shrink, two layers of heat shrink, the outer sleeve just bigger and slightly longer  than the first sleeve. It gives a bit more support and protection at the joint.

 

[Swampgecko]

20 minutes ago, MV Sunray said:

So is heatshrink covering a naked wire considered a submersible connection? 

Short term submersion only, I prefer "water resistant", unless you have used a suitable adhesive or sealant with the heatshrink.  If you don't seal it you can get some capillary draw of water into the connection. I have seen this from personal experience working on military aircraft.

[austwave]

5 hours ago, Swampgecko said:

Short term submersion only, I prefer "water resistant", unless you have used a suitable adhesive or sealant with the heatshrink.  If you don't seal it you can get some capillary draw of water into the connection. I have seen this from personal experience working on military aircraft.

I only use tinned wire and solder and glue lined heatshring but even so i find i only get about 5 years out of my trailer lights before the water gets in and corrosion follows.

All good tips though, a bit more care saves on a world of hurt when you least need it.

Edited January 22, 2017 by austwave

[fragmeister]

On 1/22/2017 at 8:13 AM, MV Sunray said:

So is heatshrink covering a naked wire considered a submersible connection? 

For submerged ( and any application if you like) Dual Wall heatshrink is the go.

It contains hot melt glue and does form a water proof connection.

 

Cheers

 

Jim

[The Incredible Hull]

2 hours ago, fragmeister said:

For submerged ( and any application if you like) Dual Wall heatshrink is the go.

It contains hot melt glue and does form a water proof connection.

 

Cheers

 

Jim

I just use 1 heatshrink and use 2 small cable ties on each end.

[Tinkicka]

Hi,

A friend in the electronics game sent me this URL when I purchased my boat. They seem to think it would work.

https://www.unols.org/sites/default/files/SessionIV_Rowe_HOT GLUE.pdf

Seems to seal OK on the trials I have conducted.

Given that it appears to be from Woods Hole (they do some deep exploration in oceans) it would appear to be sound practice.

I would like to hear other people's (more experienced) thoughts???

Tinkicka (Brett)