The Most Important Gauge On Your Boat
by Gary Caputi

The Importance of Accurate Fuel Monitoring
Today's pleasure boats are marvels of modern technology. They are better designed, built and powered than at any time in history, and affordable to a greater number of people than ever before. With these advances comes an increased level of confidence by boat owners in the reliability and safety of their vessels and much of that confidence is justified. However, there is one important area that boat manufacturers and most boat owners continue to overlook, the accurate monitoring of fuel consumption and the ability to precisely determine how much fuel is in the tank.

Running a boat is very different from driving a car. If the fuel gauge on your car is inaccurate and you run out of gas, the outcome rarely puts you in a perilous situation. In fact, it is usually just a minor inconvenience because the next gas station is probably just around the corner and if it isn't you can whip out your cell phone, call road service and you're on your way in no time. That is not the case when you run out of fuel in your boat, especially if you operate it in large lakes or in the ocean where sea conditions can vary greatly and losing power can place you in danger or land you a hefty towing bill.

Unlike your car, there are a number of factors that can influence the fuel consumption of your boat and some can change at a moment's notice. If you don't have a way to monitor the effects of those changes, they can result in unpleasant consequences. Some factors are mechanical and others are environmental. A clogged fuel injector or a ding in a propeller effects fuel consumption immediately. Fouling of your boat's bottom can increase fuel consumption gradually as the infestation gets worse. The speed you operate your boat at can greatly influence the "gallons-per-hour" burned and "miles-per-gallon" your boat will achieve. Deteriorating sea conditions can push up fuel consumption dramatically at a time when the last thing you want is to run the tank dry. Being without power and at the mercy of a storm-tossed lake or ocean is a dangerous proposition, a situation no boater wants to find himself in under any circumstances. Yet without an accurate fuel monitoring system on board how do you really know your fuel status?

The majority of boats sold today still rely on the same simplistic electro-mechanical float and gauge (which only indicates fuel level) that has been in use for more than 50 years. A system that is inherently inaccurate and has been proven undependable, prone to corrosion and failure. Few boats are equipped with a system that allows the operator to track fuel consumption while underway, a very important consideration as you will see. An educated boater operates a safe vessel and experiences fewer problems because he has the knowledge and the equipment to see warning signs that can prevent dangerous situations and costly mechanical failures from occurring. A FloScan system will allow you to do both while saving you money. Sound interesting?

FloScan Instrument Company, Inc. has been the industry leader in fuel monitoring systems for commercial trucks, aircraft and boats for over 25 years, and offers systems that are compatible with most boats on the water today. Their products are the most accurate and reliable, a fact supported by their wide acceptance by the aircraft industry and a very long list of testimonials from boat owners around the world. A FloScan is simply the most valuable instrument you can have on your boat and it can pay for itself in fuel savings alone. We are pleased to provide you with this brochure to help you understand the importance of monitoring fuel consumption on your vessel so you can join the growing fraternity of boat owners who operate safer, more economical vessels using FloScan's state-of-the-art systems.

The Fuel Guessing Game
A boat's fuel consumption in calm water is determined by the efficiency of its hull and propulsion system. But there are many more factors that come into play that most boaters fail to consider until it's too late. Come along on an ill-fated fishing trip and see if you can figure out where this captain went wrong.

A 40' twin-diesel sportfisher departs for an overnight tuna fishing trip 80 miles offshore, a trip the captain has made many times before. He knows his boat has sufficient range and usually returns with a 25 percent reserve left in the tanks. The forecast is for 15 to 20 knot east winds and 3 to 5 foot seas, subsiding overnight and then switching to the west. Nothing this boat can't handle safely.

Well, the ride out is a bit bumpier than expected due to sustained 20 knot winds with higher gusts, which generates a 5 to 7 foot head sea. With a nicer night forecast, the captain slugs his way offshore anyway. A radio call from a friend already on the fishing grounds informs the captain that the tuna action is red hot, but further out near the mouth of the canyon, an additional 15 miles. Shouldn't be a problem with the reserve, so the skipper runs the extra distance and sets up for the night. The wind dies down, as advertised, and the crew bails tuna all night long. By morning the five anglers have put 600 pounds of tuna in the fish box and the wind has begun to pick up from the west, the direction they have to run back to the inlet. The skipper trolls until 11:00 a.m. and then starts the run in, but by then the wind is blowing 15- to 20-knots and he has to make the 80-mile run back into 4- to 6-foot seas.

About 25 miles from the inlet the port engine goes down. Moments later the starboard engine coughs and dies. The captain is perplexed. This can't be happening. The fuel gauges indicate a little less than a quarter in both tanks, but the boat has run out of fuel. A call to the Coast Guard dispatches a commercial towing service since the boat was not in a life-threatening situation, just rocking uncomfortably in the waves while waiting for three hours for the tow vessel. The tow cost $1300 and the fuel filters and injectors were fouled by whatever gunk was hovering at the bottom of the tank when they bottomed out. That produced a mechanics bill of $750. True story! I know because I was on the boat. So what went wrong? The boat had made the trip before with fuel to spare.

The first factor affecting fuel consumption was the ride out in a substantial head sea, which forced the captain to run at half the boat's normal cruising speed. Since the boat was never quite on plane, the engines had to work harder to push more mass through the water. Climbing and descending the sizable waves was the equivalent of adding many miles to the trip out and the result was the boat burned almost twice as much fuel as it would have under calmer sea conditions. The extra 15 miles to the fishing spot through the head sea didn't help. The night's catch put an additional 600 pounds of weight in the boat for the ride home, which pushed the hull even deeper into the water.

While trolling the next morning, the over-confident captain didn't give his fuel situation a second thought because the gauges showed a little over half left in each tank. The return trip was also into a head sea with added weight and it taxed the remaining fuel supply by preventing the boat from running at its optimal cruising speed and adding even more distance. The last straw was the standard fuel gauges, which showed a quarter left in each tank when the engines stopped running. Like most float-driven fuel gauges, they were generally inaccurate, but especially so when the fuel level nears the bottom of the tank.

Now you know what happened, but stop and think about it. The unpleasant situation and the costs associated with running out of fuel could have been avoided if the captain had a FloScan system on board. He would have known that his fuel consumption rate on the way out was far greater than normal and taken appropriate action to prevent running dry long before he got into trouble. He would have also known exactly how much fuel he had in the tanks at all times by watching the system's digital totalizer, which accurately tracks the gallons burned from the full tanks instead of guessing at it. A FloScan system would have saved him over $2,000 that day alone, far MORE than the cost of buying one.

By the way, the captain purchased a FloScan system for the boat before his next trip, but why wait until you get into trouble before you install one on your boat? You might not be as lucky as we were on that trip. We made it back.

Run Faster & Save Fuel
Even the most basic FloScan system provides you with a very important piece of information that will help you operate your boat more efficiently, the gallons-per-hour being burned at any speed while underway. That simple bit of data can save enough fuel that the FloScan will pay for itself in a short time and, if you're like me, you might be surprised to find that your boat actually operates more economically at a higher cruising speed.

Every boat has an operating speed that provides the greatest distance covered burning the least amount of fuel. It's the "miles-per-gallon" figure we are all familiar with in cars. In boats, however, peak efficiency cannot be determined without an instrument that can provide real-time data on fuel consumption while underway. Fuel consumption can vary with changes in sea condition, something you just learned, but once you've establish the point of peak operating efficiency for your boat under favorable sea conditions you can run it more economically. Operating your boat at what we affectionately call it's "sweet spot" saves fuel and fuel is money. Running it just a few hundred RPM faster or slower can dramatically decrease the miles-per-gallon it will deliver.

Let's take a look at my runabout as an example. It's a 23' center console powered by a 225 hp outboard. Before installing a FloScan, I thought it ran most economically at 4000 RPM, which the GPS indicates is a speed of 28 miles-per-hour. It was an acceptable cruising speed and the big outboard loped along smoothly, so I assumed it must have been getting good gas mileage. Then I installed a FloScan CruiseMaster and started experimenting using a simple formula.

(Miles Per Hour ÷ Gallons Per Hour = Miles Per Gallon)

I was amazed to discover that the boat actually operated more efficiently when I pushed the engine up to 4450 RPM, attaining a speed of 36 miles-per-hour. Fuel economy didn't just go up a little, it went up enough to squeeze 50 additional miles out of a 150-gallon tank of gas! Here's how it worked.

At 4000 RPM, the boat was traveling at 28 miles-per-hour, and the FloScan showed fuel consumption at 17 gallons-per-hour. Let's do the math. Come on now, this is really basic stuff, but you can cheat and use a pocket calculator if you have to. The boat was getting 1.65 miles-per-gallon. (28 MPH ÷ 17 GPH = 1.65 MPG)

Then I checked additional throttle settings, jotted down the speed from the GPS and the gallons-per-hour from the FloScan for each and did the math. After fumbling around a little, I found the sweet spot at 4450 RPM, running 36 miles-per-hour while burning only 18 gallons-per-hour! That's a jump to 2 miles-per-gallon. Besides being extremely pleased with the results of my initial introduction to fuel savings by using a FloScan, I was curious why the boat got better overall fuel economy at a considerably higher speed. It didn't seem logical that I could run the boat faster and save fuel at the same time. The answer relates back to the hull design interacting with the propulsion unit. The hull is a deep-vee with lifting strakes. Operating at 4000 RPM, the boat was on plane, but the hull was not lifted high enough out of the water by the strakes to run at peak efficiency. At 4450 RPM, less of the hull was below the water and the engine was actually pushing less mass through it so I was gaining considerably more speed with only a marginal increase in fuel consumption.

Now if you could have a simple instrument for your boat that would allow you to operate it more economically, which in the end means you're going to have to purchase less fuel, wouldn't you run out and buy it? So what are you waiting for?

Early Warning System
As with any complex mechanical system, there are problems that arise in boats that can lead to the failure of major components and very costly repairs. Some start small and stay small, like a fouled spark plug that only drives up fuel consumption. Others start small, exhibiting few symptoms, but cause big trouble. A problem as simple as a clogged fuel injector, when left unattended, can lead to a burned valve or piston failure and what would have been a minor repair can turn into an engine rebuild or replacement. Once a minor problem becomes a major component failure, repair bills climb from a few dollars to a few thousand dollars in no time!

There is one early warning signal that accompanies a variety of minor malfunctions that an observant boat operator can pick up on before they cause a major failure-fluctuations in fuel consumption. With a FloScan you can recognize that a problem exists before it gets out of hand because once you have a FloScan on your boat, keeping a watchful eye on the gauge becomes second nature.

As you establish your boat's sweet spot, taking advantage of the fuel savings it provides, make note of the fuel consumption at a variety of RPM levels. If you know that your boat burns 17 gallons-per-hour at 4200 RPM under normal conditions and the fuel consumption suddenly changes by a few gallons in either direction, it's a signal that something is wrong. A drop of a few gallons-per-hour is not a gift from the boating gods, it usually indicates a clogged injector nozzle. You might not feel it in the engine's performance, but you can see it on the FloScan's readout as plain as day. Left unchecked it can cause one or more cylinders to run lean and overheat. In a four-stroke engine, you might get away with just burning an exhaust valve, which requires a costly top-end rebuild. In a two-stroke, the result can be even worse-a burned piston. And then it's time to replace the entire short block.Say you're running and notice that at 4200 RPM, instead of the normal 17 gallons-per-hour, the FloScan indicates a jump to 25. It could indicate a dangerous fuel leak near or on the engine, which can lead to a fire or with a gasoline engine even an explosion. A less dramatic increase to 20 gallons-per-hour is indicative of damage to the propeller. Minor damage to a propeller blade doesn't always create an imbalance, which can be felt as a vibration, but it can still increase fuel consumption considerably. A dinged blade can decrease efficiency enough to cause the boat to burn 10 to 20 percent more fuel at cruising speeds.

Here's another telltale sign. Your boat's been in the water for several months and you notice that the fuel consumption at 4200 RPM has been slowly creeping up. The boat started off at 17 gallons-per-hour, but by midseason it was 19 and now it's over 20. What's the problem? There are two possible explanations. Some engines perform more fuel efficiently at lower operating temperatures and since water temperatures are cooler in the spring and in many places warm considerably in the summer, a small shift upward in fuel consumption might occur. However, it is more likely that the bottom of the boat is fouling with marine plant growth, barnacles or, in some environments, with zebra mussels. Even though you painted the bottom, some of the newer antifouling paints require significant use of the boat to effectively repel weeds and critters. If you haven't used the boat for weeks on end fouling could be occurring, and the first indicator is a rise in fuel consumption, which tells you it's time to pull the boat and power wash the bottom. Just remember, a FloScan at your helm can keep you out of more types of trouble than just running out of fuel and save you money in more ways than just improved fuel economy. It will help you determine the normal operating parameters of your boat and can clearly indicate when there is a problem that can lead to a costly repair if it is not identified and corrected.

Accurate Trip Planning
Going on an extended trip with a boat is a wonderful experience and a great way to get away from it all. Fishermen dream about sailing away to an island where the fishing is outstanding and the crowds are left far behind. If you don't fish, cruising by boat to distant ports-of-call takes your boating experience to a whole new level.

A trip by boat, even a weekend voyage to an offshore fishing spot or a quick jaunt across the Gulf Stream to a nearby island in the Bahamas, requires planning that includes careful attention to navigation and fuel consumption. For short hops, knowing your fuel requirements in advance can help you avoid filling up in places where fuel prices are exceptionally high. If planning a trip of greater distance and duration, careful attention to charting each leg of the journey assures ample fuel to make the next landfall where fuel and provisions can be replenished. Before FloScan, the most critical component of trip planning was left to estimation. Determining a vessel's range and setting the parameters for each leg of the journey so that it falls within your known range, with acceptable reserves in case environmental factors increase consumption along the way, is critical for safety and peace of mind. Yet even today, far too many captains head out on trips without the important data provided by a FloScan.

FloScan systems have been a key component in record setting journeys on the sea and in the air. Larry Graf, president of Glacier Bay Boats, used FloScan fuel monitoring systems on his Honda-powered catamarans to set distance records for outboard powered vessels in both the Atlantic and Pacific. Planning each leg of these voyages and monitoring actual fuel consumption on the water was critical to their success.

Richard Rutan, designer and co-pilot of the Voyager (the only plane to fly non-stop around the world without refueling) chose FloScan for the critical job of monitoring fuel consumption throughout his incredible journey. Both of these pioneers chose FloScan for accuracy and unquestionable reliability! Their FloScan systems were indispensable and allowed them to push their craft beyond the limits of anyone who came before. If Larry Graf and Richard Rutan trust FloScan, you can too. There's no substitute for using the best, and FloScan is recognized for developing and manufacturing the finest fuel monitoring systems in the world!

Nothing Beats A FloScan
By now you realize that a FloScan fuel monitoring system is an indispensable tool for your boat. What else can you say about a simple device that can reduce fuel consumption while increasing range; track exactly how much fuel you have on board at all times; provide early warning of impending mechanical problems helping avoid costly repairs and frustrating down time; make trip planning a breeze; and make your time on the water safer and more economical. All while saving enough money to pay for itself in short order?

Indispensable pretty much sums it up and like any truly innovative product, FloScan has received the sincerest form of flattery -- inexpensive, poorly designed fuel monitors have come on the market that claim to be "as good as a FloScan". Unfortunately, they can't live up to their own hype because they use cheap plastic flow sensors and inexpensive electronic components. FloScan combines state-of-the-art design with the highest quality componentry using technologically advanced manufacturing techniques to create a system that provides you with unmatched accuracy and durability.

FloScan incorporates a unique opto-electronic turbine flow transducer in the critically important flow measurement portion of the system. It utilizes a neutrally buoyant rotor, which spins with the fuel between V-jewel bearings. Rotor movement is sensed when notches in the rotor interrupt an infrared light beam between an LED and phototransistor. The flow signal is sent to the meter's microprocessor, which computes this data as gallons-per-hour and tracks the total amount of fuel burned since your last fill up on a digital LCD readout. FloScan sensors are made from precision die-cast metal, making them the toughest flow sensors on the planet. In fact, they're so accurate you'll be able to tell the dock master how much fuel your boat will take before he starts pumping!

The economical CruiseMaster system for gas or diesel engine installations provides a continuous gallon-per-hour reading on an analog dial with a digital readout that tracks the total fuel consumed between each fill up.

The FloScan Multifunction Series features an all-digital display, which includes an engine hour meter, super-accurate digital tachometer, and fuel totalizer. And when interfaced with your GPS, displays either gallons-per-hour or miles-per-gallon while running with the flip of a switch.

For twin gas boats, the TwinScan system comes available with a matching Tachometer and GPH Meter, which include features such as engine RPM, engine synchronization, GPH, gallons consumed, and nautical miles-per-gallon. You'll get these features in a clean, aircraft-style instrumentation package that takes up the panel space of just two standard tachometers.

In gas applications, a single FloScan flow sensor is placed in the fuel line between the fuel filter and the fuel pump. In diesel applications, two sensors are employed, one on the feed line and another in the return line. The feed sensor tracks the fuel flowing to the engine and the return sensor subtracts the fuel that flows back to the tank. FloScan recently introduced a new flow sensor design for Detroit Diesel, EMD, and Caterpillar 3500 Series engines which cuts the installation time in half. Certain diesel engines may require fuel pulsation dampeners (supplied) to ensure accurate flow measurement. And FloScan has researched the feed and return flow rates for your diesel engine to ensure Diesel models are prepackaged with all the components necessary for specific engine brands and models so you will have everything necessary to complete an installation from start to finish.

With a model available to fit your boat, it's definitely time to invest in a Floscan fuel monitoring system. They are available at most quality marine stores and marine electronics catalogs. To locate a dealer, learn more about FloScan products, or read letters from many satisfied owners, go to our comprehensive website at www.floscan.com.

Author Biography
Gary Caputi is, above all, an avid  angler from the northeastern United States whose love of fishing and boating has guided his career. He has fished all over the world with all types of tackle and he is also a well-recognized contributor to regional and national sportfishing magazines. He has held staff positions on several and he is currently the offshore editor of Salt Water Sportsman magazine, the largest saltwater fishing periodical in the world. He is the author of Fishing for Striped Bass, the most popular book about fishing for and catching these highly regarded gamefish. He is regularly featured in fishing seminars at clubs and sportsman’s shows and enjoys teaching others how to be more successful fishermen. Gary’s experience with FloScan products goes back over ten years when he installed his first one in an outboard-powered center console. He has been telling other boaters about the importance of fuel management and singing the praises of FloScan systems ever since.