How far can our sailboat take us before we run out of gas?

Imagine you’ve taken your sailboat out on a three-hour tour. The day begins, and you’re happy on your boat. The wind is in your sails.

And then suddenly, it isn’t.

The shore is four nautical miles away, and a storm is brewing. The crew is feeling slightly disgruntled. You go to turn on the engine, and you discover you don’t have enough fuel to return to shore.

Sailors who understand gas mileage and fuel consumption won’t ever have this problem. Here’s what you need to know.

The Constants

Units of Measure

Your engine’s horsepower hp
How much fuel you have on board gallons
How fast your sailboat can go nautical miles/hour
How efficient the fuel consumption is pounds/horsepower
How much the fuel weighs pounds/gallon

 

The Constants Aboard the Sea Shanti

Units of Measure

Your engine’s horsepower 40 hp
How much fuel you have on board 60 gallons
How fast your sailboat can go 5 nautical miles/hour
How efficient the fuel consumption is .4 pounds/horsepower
How much the fuel weighs 7.2 pounds/gallon

 

The Formulas

How many gallons of fuel does the Sea Shanti use per hour?

The Formula

Gallons per hour = (Specific Fuel Consumption X Horsepower)/Fuel Specific Weight

GPH = (.4*40)/7.2 = 2.22 GPH

How long can we travel on the Sea Shanti’s fuel supplies?

The Formula

Travel Time = Gallons per hour X Gallons of Fuel Onboard

Travel Time = 2.22*60 = 133.2 hours

How far can we travel on the Sea Shanti’s fuel supplies?

The Formula

Total Distance = Time Traveled X Average Sailboat Speed Motoring

Total Distance = 133.2*5 = 666 nautical miles

BONUS: How many days can we travel on the Sea Shanti’s fuel supplies?

The Formula

Number of Days = Travel Time in Hours/Number of Hours in the Day

Number of Days = 133.2\24 = 5.55 days

In Conclusion

If you’re going to be a sailor, you’ve got to learn the risks and how to deal with them. Sometimes that involves math, a fate more terrifying than sirens.

By | 2018-03-22T17:02:21+00:00 January 25th, 2018|School|4 Comments

About the Author:

Fain is the Shanti’s official historian and emissary. He’d like to be a politician one day despite his poor mother’s pleas to the contrary. He’s in the Communist phase of puberty now, and he spends a lot of his time debating the equitable distribution of labor, particularly where the cleaning of litter boxes is concerned. He’s currently working on a novel of his own and attempting to convince Autumn that anarchy is not a viable political system.

4 Comments

  1. Ellen @ The Cynical Sailor January 26, 2018 at 2:24 pm - Reply

    I do find math a bit terrifying 🙂 We’ve never been in the position where we didn’t have enough diesel to get to a safe harbor. Not sure I ever want to experience running out.

    • Autumn Ware January 26, 2018 at 5:42 pm - Reply

      This was math that we conned our poor teenager into doing when he was asking questions about our travel plans. Fain actually wrote this. (I just hadn’t had a chance to add him to the blog users yet. He’s there now!) I can’t say as I fully follow it all, but it was cool to watch him figure it out. 🙂

  2. Steve January 31, 2018 at 3:22 pm - Reply

    Neaubeard, infamous pirate and now what appears to be a budding mathematician.

    • Autumn Ware February 7, 2018 at 5:10 pm - Reply

      Indeed! Otherwise, how will he know we’re divvying up the booty equally as all good pirates should?

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