When Replacing Electrical Items in the Mast

Re-wiring and replacing the fixtures in the mast is a task that most of us boat owners need to face at some point. Let’s address what needs to happen during this process and what is the most efficient way to do this.

First, the mast needs to be un-stepped. Therefore it could be a smart idea to handle any other items that could benefit from the mast being out. Next, begin by removing the old masthead fixture, the old steaming light fixture, and the old VHF antenna. Now remove all of the old wires and any remaining hardware. In some cases there are electrical items that need to be re-used. These items could be a radar and cable, as well as a digital wind instrument. Be sure to carefully remove these items as well and inspect them closely (now’s the time).

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Once all electrical items have been removed, you should check to see if there is a conduit present and how it may or may not be fastened. A properly installed conduit offers; no wire slap, clean wire runs, and most importantly, the ability to run additional wires or trouble shoot existing ones with ease, even when the mast is up.

Installing a conduit is a bit’ of a ‘trick of the trade’. It is best here to seek the assistance of a professional rigger if one needs to be installed. Make sure to ask your rigger what technique he or she might use. At T.R.C., we will use aluminum or PVC irrigation tubing. This type of tubing offers a sleeker connection at the joint. Our conduits are then riveted using a pair of aluminum rivets (to avoid dissimilar metals) every 3′ or so along the length of the mast. I like to counter sink these rivets because it makes it look more finished and also gives you no issues if there might be future sanding.   After the conduit is ready to go, you are now ready to fish-in a messenger line. From here you can begin to pull in your new wires. Always try and leave in a service messenger when finished. Unless the conduit is full of course, we don’t want to be misleading anyone in the future. I tend to make it a practice to pull-in the large wires or the wires with permanent ends first. Now go ahead and drill, tap, and dry fit your new fixtures. Make sure you take your time and think it through and follow the manufacturers guidelines. Never use sheet metal or self tapping screws, even if provided by some manufacturers. Always drill and tap, or rivet your fixtures along with a dab of sealant for a secure hold.

Make sure you use marine grade connectors that heat shrink. Additionally, before making any connections, slide on a piece of marine grade heat shrink tubing. Marine grade heat shrink tubing has an adhesive that is released when heated. After your connections are made and heat shrunk, make sure to provide some sort of strain relief for the cables (pictured below). Next, install the fixtures permanently using a sealant as an isolation barrier. Pull out any remaining slack at the butt of the mast. Trim all of your cables to a neat and even length. Leave enough slack for service lengths. Finally test all of the light fixtures through the mast and label the cables accordingly. As always, don’t be afraid to ask, so leave a comment or ask a question, we will reply. Thanks for the read!