Today is Thursday and I have a bareboat class going as I write this. Class started Sunday and will continue next Saturday and Sunday. Last night I received an email from one of the students with a list of questions she had come to mind over the past few days. Each and every question was really good. Some were easy and are already in the lesson plan for the next two class days.\u00a0 Others made me think.\u00a0 The two questions that made me think the most are “What is the fuel burn rate to operation for the boat we will be taking?” and “How do you figure the estimated amps used vs. battery capacity and charging.”\u00a0 My answers in the email;\u00a0as to the first question, 3\/4 to 1 gallon per hour; with the second question I tried a delaying action by saying “This answer is too long for an email.\u00a0 We can talk about it in class.”\u00a0 For 9 out of 10 people, these answers would have been good enough.\u00a0 Not this time.\u00a0 I was quite impressed when I got the next email asking for more in-depth information.\u00a0 That’s how “a captain” approaches things.\u00a0 So, for you captains out there, here is a more complete explanation.<\/p>\n
Fuel Burn Rate<\/strong>:\u00a0 Unless you happen to be in Death Valley, running out a gas in a car isn’t much more than inconvenient.\u00a0 Running out of fuel in a boat puts the boat and everyone on board at risk.\u00a0 Unfortunately, without an accurate\u00a0fuel flow meter (not something most boats have)\u00a0how much fuel you are using is a\u00a0question that is always going to be a best guess.<\/p>\n In looking at the\u00a0engine manual for a 50 horsepower motor found in many Catalina 42’s, fuel consumption rates are listed as varying from .55 to 1.3 gallons per hour.\u00a0 A number of variables enter into the calculation.\u00a0 Propeller pitch, revolutions per minute, wind, current, and waves are all factors.\u00a0 Even the condition of the bottom is a major factor, meaning the same boat in the same relative conditions may consume more fuel per hour if the bottom hasn’t been cleaned in three months.\u00a0 Over time, experience with a specific boat is going to give you a good idea of the normal fuel consumption for that boat.\u00a0 For example, I crewed on a trip from Cabo San Lucas to San Francisco on\u00a0a Catalina 42.\u00a0 We found that we\u00a0averaged .75 gallons per hour (GPH).\u00a0 In that case, we were motor sailing close hauled at approximately 2700 RPM.\u00a0 This was moving us nicely along at about\u00a07 knots.\u00a0 2700 PRM is a good cruising speed for that particular motor, so I would keep that part of the equation.\u00a0 If you are not motor sailing, then add some consumption … how much I am not sure, however I would think .25 GPH might be a reasonable overestimation.\u00a0 On that trip, we had some great conditions.\u00a0 If things were a little “bumpier” maybe add another .25 GPH.\u00a0 At this point, we are up to about 1.25 GPH, and I would be comfortable using that figure for most conditions on that specific boat.\u00a0 Now, lets use that figure in something practical.\u00a0 That same Catalina had a 48 gallon tank.\u00a0 Always leave a reserve …\u00a0in this case lets say 1\/4 tank, or 12 gallons, giving us 36 gallons of usable fuel.\u00a0 At 1.25 GPH, that allows motoring for 28.8 hours, at 7 knots\u00a0a range of about 200 miles.<\/p>\n That works great if you are motoring straight through.\u00a0 How about when you motor for a day, then sit at an anchorage for 3 or 4 days.\u00a0 During the time in the anchorage you run the motor to charge batteries.\u00a0 Maybe that’s where the .55 GPH comes in.\u00a0 If so, don’t forget to count that time when figuring range.\u00a0 So let’s say you anchor\u00a08 days over a two week bareboat charter,\u00a0running the motor\u00a03 hours a day to charge your batteries (whether or not that’s enough is the topic of “Part II.”)\u00a0 You just lost about 13 gallons of your 36 available gallons, meaning you only have about 23 gallons available to use.\u00a0 A range of approximately 130 miles.<\/p>\n How does all this work in real life?\u00a0 I love Mexico.\u00a0 Chartering out of La Paz is outstanding.\u00a0 A great plan is to go as far north as Agua Verde, about 100 miles away.\u00a0 I hope you have good wind, because if not, given the above numbers you are going to be pretty much out of fuel about 70 miles short coming home.\u00a0 I know, I know, that extra 12 gallons of reserve will get you 67 of those miles.\u00a0 Close but no cigar.\u00a0 You are still out of fuel.\u00a0 And you are taking a chance on sucking all sorts of nasty stuff (like algae and water) off the bottom of the tank, clogging the fuel filters and possibly the injectors, meaning a sizable repair bill.<\/p>\n Even on a day sail all of this is good stuff to know.\u00a0 Always check your fuel level.\u00a0 I would recommend not trusting the gauge.\u00a0 Always check the tank itself.\u00a0 Know how much fuel you are starting with and an estimate of your hourly consumption.\u00a0 I like to use 3\/4 GPH for the Bronze diesel powered boats, 1 GPH for the Silver Fleet boats, and 1.25 GPH for Gold Fleet boats.<\/p>\n Be safe out there.\u00a0\u00a0As a friend of mine likes to say, there are three types of sailors.\u00a0 Beginning sailors …\u00a0paranoid sailors … and retired sailors.\u00a0 A little paranoia regarding fuel consumption is not a bad thing.<\/p>\n","protected":false},"excerpt":{"rendered":" Today is Thursday and I have a bareboat class going as I write this. Class started Sunday and will continue next Saturday and Sunday. Last night I received an email from one of the students with a list of questions … Continue reading