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Written by Alan Earls. 

Glistening powerboats, whether cruising Biscayne Bay or wending their way around Maine’s Mount Desert Island, have a secret – they are packed full of electronics that needs maintenance and upgrades.

There are plenty of wonderful things about new (or recently built) boats coming on the market. Yet, there is a hidden challenge that aftermarket organizations and their technicians, from Maine to Florida, are looking to address. For example, some boats, even new ones, aren’t able to deliver the needed power for all of the devices on board—electronics, pumps, galley equipment, stereos, TVs, etc. The result can be electronics that don’t work properly, machinery that blinks off, damaged equipment, and worst of all—warm beer. That means opportunity for those with electronics know-how.

According to a range of voices from across the ‘waterfront’ – the good news is that the majority of vessels are robust enough to live up to customer expectations – but some can be marginal. Just as worrisome, cut rate builders, resellers, and DIYers may not understand or may not care about what’s at stake when the adding or upgrading features.

Watt are they thinking?

There is probably no simple way of comparing yesterday’s boats with today’s in terms of power consumption but there is little doubt that there is a consumer demand for more power, usually gratified by builders and dealers. Generally speaking, demand for electrical power has increased on recreational boats, however notes a Coast Guard source, there is no easy way to the quantify the increase. The development of consumer electronics such as navigation systems, enhanced lighting, and other amenities appears to have consumer appeal, and boat builders want to meet consumer demand by including these amenities

For some perspective consider that in living memory, most boats had only the most rudimentary electrical system: navigation lights and limited interior lighting and perhaps a pump and a radio.  Then came radar, fish-finding sonar, stereo sound systems, Internet access, and microwave ovens and even the ultimate power hog, air conditioning.

A boater with a product review site, boasts have having a refrigerator, microwave, pump and two twelve-volt batteries that are charged from a generator.  The electrical and electronic picture grows more complex when you realize that they can run on

“shore power,” as well as an onboard generator. And while there might be some purists – the sailboat types – who want wind and waves, not amenities – they are few in number.

Facts are facts

Boats can’t escape Ohm’s law. It helps dictate many of the immutable limits to what power systems, whether AC or DC, can deliver.

For example, there is the issue of peak load versus normal draw.  The former is when one or more pieces of equipment, especially refrigerators and air conditioners, cycle on, typically hitting their maximum power requirements in the first few moments of operations. If multiple power-hungry devices do this at the same time, it can tax even the best conceived power system.

Equipment vendors spend a lot of time, effort, and money working with boat builders to make sure when customers get their boats, key equipment like navigation gear has sufficient, reliable power.

The good news is a lot of newer electronics are not as power hungry as in the past, but boats are coming so well equipped from the factory that there are still challenges.

In the past, customers tended to buy a basic boat and then hire a tech or electronics dealer to add accessories. Now it is more turnkey, customers just “drive it off the lot.”

Still, in buying a new boat, even one that is well equipped, a customer might choose to add a windlass or generator set. Typically, boats have a wiring harness to accommodate some additions. But a knowledgeable tech needs to figure out what will work and make additions if needed.

Broadly, there is an increase in power demand. What’s driving the increase is the same things that are being seen in homes and motor vehicles.  People just have more tech available and that brings more features to make products better and improve the boating experience. Without sufficient power and the right wiring, boat owners can drain down a battery or overload a charger. So, everyone, boat owners, boat builders, and after-market techs, need to be mindful of not only continuous power demands but peak loads, too.

To deliver the right power, dealers and techs need to figure out how to engineer for demand, for example, adding power converters and AC/DC converters.  Some of these systems like big DC stereo systems, exceed what’s typically available in terms of battery power, which can mean the need to install an AC/DC converter.

But those with experience in the field say that the wiring on a boat is very difficult to change once it is installed, posing a challenge that technicians need to surmount.  They must do careful load calculation to make sure they can deliver enough power.

And, if you have a boat that is 15 or 20 years old and you want to run a new AC if the boat wasn’t intended for that you might have to go back and substantially rethink the power systems.

And there is no going back. Given the ruggedness and efficiency of most modern systems, the benefits outweigh the costs of building more power.

Standards Keep an Industry in Balance

American Boat and Yacht Council (ABYC), a non-profit that dates back to 1954, is a standards development member of the American National Standards Institute. It builds its specific guidance on many other industry standards.  But its standards are the go-to reference for boat builders, installers and anyone else that has a hand in deciding how a vessel is engineered.  Standards are on a three-year review cycle so ABYC can jump on trends and stay up to date.

The ABYC standards are based on a wide range of other published standards, in particular, the National Fire Protection Association’s National Electrical Code. But influence also comes from IEEE, ISO, and other groups.

The ABYC E-11 standard applies to alternating current (AC) electrical systems on boats operating at frequencies of 50 or 60 hertz and less than 300 volts, including shore power systems up to the point of connection to the shore outlet and including the shore power cable as well as direct current (DC) electrical systems on boats operating at 60 volts or less. It excludes wiring that is part of an outboard motor or most of the wiring that forms a part of an inboard motor assembly. Its component documents are:

  • A-1, Marine Liquefied Petroleum Gas (LPG) Systems
  • A-3, Galley Stoves
  • A-16, Electric Navigation Lights
  • A-22, Marine Compressed Natural Gas (CNG) Systems
  • A-28, Galvanic Isolators
  • A-31, Battery Chargers and Inverters
  • A-32, Power Conversion Equipment and Systems
  • C-1500, Ignition Protection for Marine Products
  • E-2, Cathodic Protection
  • E-10, Storage Batteries
  • E-30, Electric Propulsion Systems
  • H-2, Ventilation of Boats Using Gasoline
  • H-24, Gasoline Fuel Systems
  • H-33, Diesel Fuel Systems
  • T-5, Safety Signs and Labels
  • TE-4, Lightning Protection
  • TH-22, Educational Information About Carbon Monoxide
  • TH-23, Design, Construction, and Testing of Boats in Consideration of Carbon Monoxide

As far as the wiring “backbone” and the ability to add more equipment, the standards are relevant not just for builders and dealers but also for owners.  And, while the standards have been evolving since the 1950s, they are not created in a vacuum.

It is also important to understand that unlike some standard, the ABYC standards themselves are not mandated, they are purely advisory. But most of their elements appear in barebones form in 33CFR, which covers inboard boats.

In addition to helping ensure safety and satisfactory boat operation, the ABYC standards have the additional virtue of being comparatively easy to comply with because they are written to be easy to understand and they don’t impose difficult requirements.

ABYC is constantly monitoring trends and folding them into their three-year cycle.  For example, ABYC began working on lithium battery and electric propulsion issues even before SAE published anything on the topic.

The bottom line is that even if core ABYC documents don’t cover something, the organization will usually develop a technical information report that will eventually morph into a standard.

In short, ABYC is another great resource for the tech community, especially for those moving into this specialized area.