If you need to remove the rub rail to access the wiring to the navigation sidelight lamps, you should plan to replace ALL of the wiring. The cost of the wire will be modest, and by replacing it you can provide for many years of no-trouble operation. I advise against trying to make a butt-splice repair of the wiring under the rub rail.
Actually, I advise against ANY butt-splice of wiring on a small boat. If the electrical distribution center is at the helm of a small boat, and the helm is roughly amidships, then, for example, on a 25-foot boat the longest conductor is likely to only be slightly longer than half the boat length. It seems very unnecessary to splice conductors together in order to make a run of wire end-to-end that won't be much longer than half the boat length. In some wiring, it will be inevitable that a butt-splice must be used, typically if a pre-wired connector with a pigtail of wires is provided for some purpose. But absent some inevitable necessity for a butt-splice, they should be avoided.
The GRAY-BLACK two-conductor flat cable may be hard to find. Alternative cable may be:
- using a jacketed 16-AWG marine grade duplex cable; the jacket will increase the size of the cable and may cause problems in fitting it under the rub rail; the wire colors won't be GRAY and BLACK
- use individual 16-AWG conductors , which can easily be obtained with GRAY and BLACK insulation; these may be harder to wrestle in place under the rub rail
- use a flat two-pair cable intended for landscaping, but generally not tinned conductors.
Below are links to possible vendors of each type of cable mentioned above.
Marine-grade flat two-conductor jacketed cable, selling for about $39 for 100-feet:
RED/YELLOW or RED/BLACK
http://www.genuinedealz.com/16-awg-gaug ... uplex-flatIndividual marine grade 16-AWG conductors, selling for about $18 for 100-feet
GRAY:
http://www.genuinedealz.com/16-awg-gaug ... grade-grayBLACK:
http://www.genuinedealz.com/16-awg-gaug ... rade-blackLandscape wire, unfortunately bare copper conductors, not tinned, for about $22 for 75-feet
BLACK/BLACK:
https://www.homedepot.com/p/Southwire-7 ... /308403420I have not performed a complete replacement of the navigation lamp wiring under the rub rail on my own boat, but my preference would be to use marine grade wire. I would get a small sample of the jacketed marine-grade flat two-conductor cable, and assess if the cable would be possible to fit under the rub rail without too much difficulty. If the jacketed cable were too big physically for a good fit, I would revert to using individual conductors. Handling four individual conductors and trying to fit them back in place under the rub rail might be tedious, but I am sure it can be done.
A final alternative for wire might be to try to purchase some from Boston Whaler, although I expect their per-foot price would be higher than generic wire on the market.
If you use a generic two-conductor cable the wire insulation color won't be the OEM color scheme. You can re-mark the wire when it comes to the electrical panel by using SCOTCH 35 Color Vinyl Electrical Tape. Of course, black tape is easy to find. Gray tape is available, too, but perhaps harder to find.
Also, I don't see that there is a necessity to run completely separate cables to each sidelight lamp. If there is room, you could make a connection at the first sidelight lamp between the two-pair conductor that supplies the power, the lamp conductors, and an extension two-pair conductor to run to the other lamp. Of course, this depends on how much room is available under the lamp or in the lamp housing.
A final option may be to use conductors of 18-AWG to save space. However, finding marine-grade two-conductor flat cable in 18-AWG is difficult. There is a general recommendation that the smallest conductor size in boat wiring should be 16-AWG, no matter what current is involved.
The vendor GENUINEDEALZ is a good source. I have purchased marine-grade wire from them in the past. Their prices are very good. The wire they sent was often marked with the ANCOR brand name, although they do not advertise or guarantee you will get ANCOR-branded wire. The non-ANCOR brande wire was of similar grade and quality.