Geoff Custer

Geoff Custer

Rewiring

Safety and function dictate how to handle problems with your boat's electrical system. Geoff Custer, electrical head at Townsend Bay Marine, shares his experience on how to cure system overloads, make your boat safer and keep up with modern electronics. Here are some insights every boat owner should know.

The study of electricity and its practical applications have been a life-long pursuit for Geoff Custer. Geoff began experimenting, accidentally, with electricity at the age of four. This was followed by a continuous passion with electric trains. During Boy Scouts, Geoff became interested in amateur radio and obtained his first license at the age of fourteen. He studied electronics engineering at Oregon Technical Institute. Geoff maintained and operated a 1200 kW diesel power plant for the United States Air Force for six years and then became the site electrician. His marine electrical career began twenty-five years ago at Puget Sound Naval Shipyard where Geoff repaired the electrical systems aboard a variety of United States Navy vessels. After graduating from the Northwest School of Wooden Boat Building in Port Townsend, Geoff began a career in the custom boat business. He has repaired, designed, and installed electrical systems on many private and commercial vessels up to 160 feet in length. During this time, Geoff also obtained a General Radiotelephone Operator's License and American Boat and Yacht Council certification. Geoff has held the position of electrical department supervisor at Townsend Bay Marine for six years.

Over time vibration from use and all of the elements take their toll on any boat. The insulation for the wiring gets brittle, and connections get corroded. Often circuits become burdened or loose. The AC/DC system that had additions made to it can overload the circuit breaker. Even if nothing has been added or changed, age alone is taxing on any electrical system. The topics Geoff discusses are:

Scope

It is usually more practical to pull out the old system and put in a brand new one. There will be less upkeep with a new system. Adding to an old system takes more time in initial labor and there will be more repair work down the line, adding expense where it could be prevented. The best time to do a rewire is during a refit as at that time all of the wiring is exposed and access is quick and easy. Most of all a new rewire ensures safety. An alarming amount of boat fires are due to wiring--as wiring deteriorates it gets hotter and hotter. Our awareness of the electricity around us is generally passive: when we flip a switch, we don’t think about what is really happening and the heat that is generated in the process. Vibration heat and moisture take a tremendous toll on the electrical systems in your yacht. Over time a failing circuit can create enough heat to start a fire.

Bilges

Professionals tend to avoid wiring in the bilge area, but sometimes it cannot be helped due to limited options. The environment is hostile and safety is the goal. Engine rooms are also difficult since they reach high temperatures when the engine is running.

Planning

It is best to know how you like to use your boat to determine the approach of a rewiring project. During consultation with the yard, discuss your boating needs. Go over whether you cruise frequently, or you prefer to stay at the dock plugged into shore power. Maybe sitting at anchorage powered by an inverter and a battery bank is more your style. If you are running all the time with a genset going you won't need as much house battery capacity as you will in an anchorage; especially an anchorage where the noise of the generator will be bothersome. Another piece is to consider the electrical load for your yacht. Think ahead about things that you might want in the future but don’t have or need immediately so you can be prepared. Sailboats are mostly DC powered--just running an alternator off the engine to charge the batteries. Powerboats are typically AC so you need AC generation constantly or inverters to run from your battery bank. All those generation systems need to be sized to your load.

Panels

New panels and replacing the spaghetti mess of wiring is a grand idea. In your box there are in all likelihood many different signatures of people who have done electrical work on your yacht; some are qualified, and others are novice at best. Mistakes with electricity can be tragic. Even if you choose not to go the route of a full rewire, a new panel box and circuit breakers are well worth your while.

Wire-ways

Ideally, the space for wiring should not be shared. American Yacht and Boat Council require wire support fairly close together. Often in older boats there is no wire support. Wiring is dragged through lockers or lying in the bilge allowing the wire to move. You should be able to follow a wire easily from where it enters a compartment until it leaves a compartment. All wires will be labeled as to source and destination. By doing so, maintenance and repair is much easier, which saves you money in the end.

Documentation

Any changes made to your boat should be documented appropriately. Older boats are a little trickier by virtue of time, as things are misplaced and easily slip through the cracks. Some boat builders do not make documents so record keeping is much more of a challenge. Do what you can to compensate. Keep neat records of any changes made on your yacht, and store them in a safe dry place.

Battery Banks

In designing your battery banks, you need to determine how they will be used. A separate starting battery bank for your engines and a separate house bank for the house loads is recommended. An AC board can have a separate battery for it as well. Taking these precautions will allow a margin for error without worry of being stranded. If everything else is dead, you can still start up and get moving.

Batteries

Lead acid batteries are the cheapest and the most commonly used of all. Make sure the water level is monitored and topped off. And even more importantly be habitual about keeping the acid contained. Not only will it eat through your clothes and anything that it touches, but it also releases hydrogen gas, which can be dangerous. For that reason the battery compartments must be ventilated.

Voltage Drop

If you have a 12 or 24 volt boat there is a concern about voltage drop. The American Boat and Yacht Association calls for 3 percent voltage drop over 30 feet with critical circuits like bilge pumps or VHF radios. Sometimes people are shocked at the size of the wire necessary to stay within that guideline. With other, less-critical circuits a 10 percent voltage drop is acceptable. With any system voltage drop needs to be tended to, although with high-voltage systems it's a little easier to handle. For example, for the same load a 24 volt system can use a smaller wire size than a 12 volt system. In any DC system the feeder cables are much bigger than you might think that they need to be. An ampacity table will tell you how much voltage it will carry, but it will not tell you how far it will carry without loss. In high load situations these things are important things to think about.

Lugs

For a good electrical connection the lugs need to be sized properly for the wire and its connection. There is an appropriate crimper for each type of lug available. Crimping needs to be done right, not too much, not too little. Under-crimping causes a poor connection, and over-crimping can crush the wire and damage the lug. Neither situation is good. Most connections today are mechanical rather than soldered because of reliability and safety.

Shrink Tubing

In damp areas like bilges shrink tubing is critical. In exterior areas it is equally essential. In dry areas like the distribution panel shrink tubing is not as important. Battery terminals or open-ended lugs need to be sealed from moisture. Adhesive lined shrink tubing affords an extra spot of sealing. Anywhere there may be a damp area inside or out requires shrink tubing.

Electronics

The options are infinite when it comes to electronics for your yacht. Naturally, much boils down to how you use your boat. Marine electronics is a dynamic, ever-changing field and it is crucial to hire a professional that keeps on top of new technology. Choosing the right radar, GPS, depth sounder, and chart plotter package is tedious. Some people love gadgets and a bounty of information, and some do not. Knowing your technical level will help you decide how to get a good installation and make your yachting experience safer and more enjoyable.

Bonding Systems

The bonding system for a non-metallic hull is important. Aluminum and steel hulls are bonding systems in and of themselves. Stray current corrosion can be devastating for a vessel. A bonding system provides a safety ground for the passengers on board by grounding all of the electrical devices together giving them a path to ground. By doing so circuit breakers can trip if there is an electrical fault without making metal pieces on the yacht energized. Since boats are made of dissimilar metals such as stainless steel, aluminum, copper, steel, and bronze, an effective bonding system can protect against electrolysis. Tying the metals together in one electrical system and securing them with zinc is important, but especially so for wooden boats.

Lightning Protection

Concepts such as lightning protection can be as dazzling as lightning itself. Frequently a cone of protection over the yacht reduces the odds of being struck. A lightning rod at the top with whiskers is a common device used for lightning protection. Many believe that a rod with dense wire down to the keel connecting to a bronze plate provides a safe path for lightning. Your cable needs to be accurately sized and run directly to the grounding plate without any bend or blocking otherwise the lightning will blow out the corner. Whatever means you choose to prevent being struck by lightning is ideal whether it is a lightning rod or underwater bronze plates. Keeping yourself safe within the cone and outside of the potential of being struck ensures safe cruising in unpredictable and/or problematic weather.

Charging Systems

Learning how you are going to use your yacht and what sort of activities you visualize while on board is fundamental. There is a wide variety of things that can be overlooked. For example, consider whether you will have a hair dryer used by yourself or a passenger. Perhaps a microwave oven, and maybe air-conditioning or a television with video might be part of your plan. The battery bank should be sized appropriately, as well as a re-charger for the battery. By evaluating all of the possible variables you can have an idea of your yachting desires, which translates to quality time.

Long Distance Travel

Nothing really needs to be adjusted or designed differently with electrical integrity when going abroad on your yacht or traveling great distances. However, upon embarking on a long voyage having a surplus of spare fuses, extra light bulbs, and alternator parts can make for a more pleasant and ultimately a safer journey.

Alternative Energy

Solar and wind power are a current topic of interest. Many people enjoy spending a few days anchorage without using their generator. Solar and wind are feasible options for replenishing DC batteries, as they are free to use. More and more powerboats today are utilizing these resources. Solar power here in the Pacific Northwest is great because of the angle of the sun. Conversely, in southern regions where the sun is more direct the solar panels become extremely hot. When solar panels get too hot they are less efficient.