Surveying Fiberglass Power Boats
by David Pascoe
15. Electrical Systems 323
Stray Current/Galvanic Corrosion Problems 326
Clean Dry Environment 328
Proper Securement 329
Wire Splices 329
Steel Junction Boxes 330
Bilge Water 332
Understanding Grounding 333
Dock Ground Problems 334
Galvanic Isolators 334
Surveying the System 335
AC System Check Out 335
Ground Circuit Test 336
Line Voltage Drop 336
Circuit Breakers 337
Main Panel Boxes 338
Power Supply Protection 339
What Is Electrolysis? 340
Sub Circuits 342
AC Generators 343
Generator Output 344
Service Outlets 344
DC Systems 345
Battery Location 345
Typical Equipment Amperage Draw 346
Battery Charging 348
Battery Testing 349
In-Line Fuses 350
Excerpt: Chapter 15
Surveying the electrical system in the course of conducting a pre-purchase survey does not mean performing a full-scale electrical system analysis.
Rather it is a more cursory inspection and general test operation that includes an attempt to determine if the systems meet basic requirements within reasonable limits, meaning within the surveyor's physical ability to do so, and within the definition of the term "survey". It also includes the search for defective, damaged or substandard installations.
One of the greatest advances in marine safety and standards in the last 20 years has been in electrical systems. Even 20 years ago it was very common to find poorly designed systems with substandard components.
Today, it is rare, although that is not to say that a few builders don't do a pretty bad job of it. However, most of the problems posed by electrical systems appear in older boats, not so much because systems deteriorate, or were poorly designed, but as a result of years worth of substandard alterations, additions and repairs.
In other words, jury-rigged wiring. It almost seems axiomatic that whenever new electrical equipment is added to a vessel, the wiring is strung out helter-skelter, patched and pieced together in whatever manner is most convenient, and with complete disregard for its appearance or safety.
When old circuits are no longer needed, the wires are cut and left in place so that no one knows whether they're hot or dead. Old boats are usually full of discontinued circuits. When new circuits are added, the power feed is often doubled up on a circuit breaker, or even taken directly off a battery.
Sometimes an in-line fuse is added at some bizarre location where no one will ever find it. And on an on. These are among the many things surveyors have to contend with.
The question inevitably arises as to what is safe and what is not. Quality builders don't go to all that trouble of making painstakingly neat wiring installations that hardly no one ever sees for nothing.
Neat, intelligible electrical systems go to the heart of safety and ease of maintenance. Sloppy wiring systems can be extremely difficult to search out when something goes wrong. Sloppy wiring always poses the danger of accidental damage. It is also an indicator of a builder who has little regard for safety.
A well-designed electrical system is one that is neat, orderly and intelligibly laid out in such a manner that circuits can be quickly searched out for faults. As you have probably noticed, the better builders usually have the circuits numbered and the wires properly color coded.
Wiring that takes off in all directions and disappears into innumerable and inaccessible holes does not qualify for a well-planned system. In fact, it is the hallmark of no planning. For the most part, care in installation equates with care in design and planning.
Most high production boats have pre-engineered systems. That means that a trained electrician designed the system before the boat was built, not during construction. Most builders create a substantial part of the electrical system "on the bench," so that every boat of that particular model has more or less the same identical system.
How often this is true is usually dependent on the size of the production run. If it's only a few boats, or custom built, more than likely the system was not pre-engineered, but "wired up" as the boat is being built. Or, in other words, a seat-of-the-pants wiring job.
This is the type that the surveyor has to be most careful with. One look at Fig. 15-1 leaves little doubt as to which type of system this is; the result speaks for itself. This is an Egg Harbor 54 sport fish built at the time the company went bankrupt and apparently didn't have the resources to do the job right.
(Additional spaces are added for easy screen reading.)
- 2nd Edition
by David H. Pascoe
Publisher: D. H. Pascoe & Co., Inc.
David Pascoe - Biography
David Pascoe is a second generation marine surveyor in his family who began his surveying career at age 16 as an apprentice in 1965 as the era of wooden boats was drawing to a close.
Certified by the National Association of Marine Surveyors in 1972, he has conducted over 5,000 pre purchase surveys in addition to having conducted hundreds of boating accident investigations, including fires, sinkings, hull failures and machinery failure analysis.
Over forty years of knowledge and experience are brought to bear in following books. David Pascoe is the author of:
- "Mid Size Power Boats" (2003)
- "Buyers’ Guide to Outboard Boats" (2002)
- "Surveying Fiberglass Power Boats" (2001, 2nd Edition - 2005)
- "Marine Investigations" (2004).
In addition to readers in the United States, boaters and boat industry professionals worldwide from over 70 countries have purchased David Pascoe's books, since introduction of his first book in 2001.
In 2012, David Pascoe has retired from marine surveying business at age 65.