Fuel efficient boat?

Discussion in 'Boating' started by DANZIG, Dec 1, 2007.

  1. DANZIG

    DANZIG New Member

    Messages:
    6,672
    State:
    West Virginia
    With fuel prices climbing I have been wondering a couple things.

    First, (aside from the obvious, the type of motor, a good tune-up and removing unnecessary weight) what a person can do with the boat to help with fuel efficiency. A good coat of wax, certainly, but are there any other tricks to help out?

    Second, just out of curiosity, what style of boat is more fuel efficient?
    Off the top of my head, I would think a bass boat type style, on account of the low profile.

    Any thoughts?
     
  2. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    Good question. I'd think a flat bottom jon boat would be more efficient as all it does is ride on top of the water. Bass boats have too big of an engine to be considered fuel efficient.

    Reading about Congress trying to set the average mpg for autos to 35 mpg, we had better be doing something with these old style outboards or were gonna be back to oars. God, what a thought.
     

  3. BLKCLOUD

    BLKCLOUD New Member

    Messages:
    378
    State:
    Pulaski Tn
    purchase a new motor..
    with that said, I used to run a 20 foot bass boat with a 1989 200 hp Johnson GT.. I kid you not..it drank 20 gallons per hour at 60 mph.. 3 miles per gallon
    I now have a new 2008 Merc optimax..175hp on a 22' deck boat..it will run 48-50 mph.it averages 6.5 miles per gallon..
    the new motors have really come a long way.
     
  4. Mr.T

    Mr.T New Member

    Messages:
    2,553
    State:
    MO
    Run the motor at about 2/3 throttle and you'll burn a whole lot less gas, no matter what boat it is - there's a sweet spot where you get best fuel economy, typically in the neighborhood of 3000-4000 rpm -- above that and below that you're miles per gallon will suffer. Varies by motor, boat and prop combination of course.
     
  5. catfish kenny

    catfish kenny New Member

    Messages:
    6,064
    State:
    Iowa
    OK what is the differance in props....say a 2 blade or three etc.?
     
  6. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Nothing more efficient then a flat bottom boat that is well trimmed.
    A well trimmed flat bottom boat is on plane when its sitting still. There is really no noticable hull attitude transition between sitting still and going 30 MPH.
     
  7. Katmandeux

    Katmandeux New Member

    Messages:
    1,618
    State:
    Checotah, Oklahoma
    A displacement hull is the most efficient.

    Watch a sailboat under power sometime...gets where it's going with no noise, fuss, wake...it just glides by, using a tiny engine, and pints of fuel.

    Of course, they draw more water than a planing hull, on plane.

    Canoes are another good example, and they draw next to nothing.
     
  8. Pirate Jerry

    Pirate Jerry New Member

    Messages:
    613
    State:
    Yulee Florida
    The higher a boat sits (Less hull in the water)when not moving the more efficient it will be provided it is a planing hull and has enough power to get on plane and stay there. A displacement hull is the least efficient as it has to push water equal to the weight of the loaded boat out of the way to move, thus the name "displacement hull". A boat that will get up on plane quickly then stay on plane with a reduced throttle setting will give you better economy.
    After an engine failure on an 18 foot modified V with 4 people and gear on board I had to use my 3 1/2 HP slow trolling motor to get home. Yep, quietly and gently and like the sailboats, very, very slowly (maybe 4 MPH) made it home using only pints of fuel.
     
  9. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Displacement hulls are effecient when you define efficient.
    You can have 25 foot displacement hull that will reach hull speed with a 10 horse diesel engine.

    Yes thats efficient as heck for a boat that size. Try that at home with the bass tracker or the pontoon.

    Now to hull speed. The way I understand it.
    That displacement vessel has a terminal velocity, or hull speed.
    If you can reach 13 knots with a 10 horse diesel and 13 knots is hull speed then you could cram a 30 horse diesel in it and it would go 13 knots!

    So yes, displacement hulls are effecient as all get out. More effecient then a planing vessel viewed in the proper realm.
    If you want to look at it purely in terms of speed as most people do, no, a displacement vessel would not be very effecient.

    So yes Lawrence, if I'm willing to catfish from a displacement vessel ( I'm open to the idea on the right waters) I could travel all over my catfish hunting grounds for pennies compared to what an outboard would cost to operate. I guarantee we'd all catch more fish if we were limited to a displacement vessel:smile2:
    Just leave the porch light on him, I suspect I'll be late getting home.
     
  10. cantstopgrandma

    cantstopgrandma New Member

    Messages:
    955
    State:
    MD
    The most fuel efficient boat is a kayak.....takes no gas at all to power, and moves pretty good. With a motor, i'd say a flat bottom jon boat is about as efficient as can be because they basically ride on top of the water.....get plenty of motor for it, and it'll be great. for example, i bought a 14'x48" flatbottom jon this year, put an 8hp on it, and it goes as fast as the 8hp pushed a much smaller 12'x32" V-bottom. Then bought a 25hp 2 stroke, and she'll plane at half throttle. I dont hafta run it very hard because its got plenty of power. I dont know about mpg, but the way i been running it, she burns less than a gallon an hour. 29mph top speed, 22 cruising a little better than half throttle. I reckon that aint too awful bad, and no more hours than we've put on the new motor, she'll probly loosen up a bit and get a tad more efficient.
     
  11. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    I would like to build a displacement vessel to cruise the Intercoastal on AFTER I retire. I can take a week to get it out the slip if I want to then.:big_smile:
     
  12. Pirate Jerry

    Pirate Jerry New Member

    Messages:
    613
    State:
    Yulee Florida
    Thats the key. Different strokes for different folks.
    Planing hull : Dang, I gotta get there before somebody catches the last one !!!

    Displacement hull : No problem man, there's always some left...
     
  13. Kelmar

    Kelmar New Member

    Messages:
    30
    State:
    Bixby, Oklahoma
    Lets not forget about the semi-displacement hull. Bought me a 1983 22ft. Bayliner 2270 Explorer about six years ago......luv it.....just luv it! It has a displacement or hull speed of about 6.5 mph. If you need to get somewhere it will cruise at about 17 mph. Boat will hold more stuff than you could care to take. 115 hp volvo penta that sips fuel with one barrel carb. Loaded for fun, 5000 lb or better. Have spent many days on the Navigation channel puttin around at 6 mph. Not as efficient as a true displacement or planing hull, kind of a compromise of both. I also have a 26ft. 1981 2670 Explorer I am rebuilding. Same style of boat only bigger. For retirement I also want trawler/barge. Thats the ticket!

    Mark
     

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  14. hookman571

    hookman571 New Member

    Messages:
    176
    State:
    Maryland
    2072 Grizzly by TRACKER. 50 HP E-TECH with tiller arm. 10 MPG Top speed about 33 mph.(With 2 men) 1000 lbs of boat. 3 mph at idle. Very stable. Great Catfishing, Rockfishing, Crabbing and Cruising boat. Most importantly, my wife loves it. I'm a lucky man.
     
  15. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    In a semi displacement I want 65 feet and 3000Hp in diesels sipping 90 GPH at 40 knots.:big_smile:
     
  16. mverick

    mverick New Member

    Messages:
    16
    State:
    il
    Balance the load in your boat and run at just planing speed and have the prop design to fit in that sweet spot on it's torque curve.

    Or you can idle for hours. Just takes forever to get there.
     
  17. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Higher fuel prices are going to make alternative boat building materials more popular.
    Expect to see more and more carbon fiber machines.
    Even the home built stitch and glue boats are big fuel savers. They weigh less then fiberglass or aluminum and require less horsepower for the same performance.

    Pangas have already become alot more popular in the states. They offer alot of boat at low horsepower because of the beam.
    They are also proven hulls. They've been run well offshore all over the world with small engine packages.

    The problem with the carbon fiber boats is the labor required to build them and the cost of the materials.
    Right now they are expensive but when manufacturers start switching over and they figure out how to produce hulls at a quicker pace the price will come down.
    The same thing is happening in the LCD and Plasma TV markets right now.
    The cost of manufacturing is dropping due to experience with the product and streamlining manufacturing using that experience.
     
  18. SUNDROP

    SUNDROP New Member

    Messages:
    395
    State:
    Washington
    What about catmaran style hulls? less resistance due to less hull contact with the water and a stable ride. Not as good on fuel as a flat but great wavebuster!
     
  19. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    My 2003 War-Eagle 2072-SLDV with a 12 degree hull and a 2005 Suzuki 140 4-stroke gets 8+ MPG running 30 + MPH That is running the motor at a around 4100 or 4200. Hard to beat.
    I only Hope when I get it sold and Get the Lund 1825 Pro Guide. That the 90 Mercury 4-stroke will also get 5 or so.
    Pete
     
  20. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    The biggest problem with a catamaran is what they draft.
    A full traditional hull will draft half as much as the same size catamaran will.
    You essentially are floating a boat with alot less hull volume which makes it draft more.
    The more draft, the more horsepower.

    No doubt they make good rough water hulls though because of less volume.
    Thats one thing that makes the panga what it is. Its narrower beam is less drag, less hull footprint. They run these things way offshore with what I deem a small engine.
    One 25'x7.5' panga I know of can be powered with 75-125 horsepower.
    Thats alot of boat with little horsepower and it'll handle some bad seas.
    Smaller pangas like the 21 footers take less.

    One of the home builders I know of built a composite 19 foot center console offshore boat. He powered with 115 4 stroke and is hitting 60 MPH.
    He runs 80 miles offshore on this boat all the time.

    Another boat is a composite 20x8 flats boat. She'll float in 2" or less. Her PPI at DWL is 413 pounds. That means it takes 413 pounds of added weight to sink it another inch lower in the water. In a stripped flats fishing form a 25 horse will push her 30 MPH but you can hang a 50 on it. Its a massive boat.

    Another would be a composite 18' flat bottomed dory. 5" draft. 40-70 HP.
    A 40 horsepower will plane this boat and carry it to speeds of 30MPH. About as fast as you want to go on this hull. Its not a speed hull. its designed for close in offshore work. She'll take alot of crap that the ocean has to offer with the right man behind the wheel. Seen pictures of a 16 foot version of this boat doing its thing in swells as high as my house including turning around on the face of the swell. At mid ship the freeboard is only around 13".
    One of the builders of the 16' version has run his from Miami to the Bahamas and back. I agree that 160 mile round trip is stupid but it handles it. He wanted to fish in the Bahamas.

    Right now if you are looking for alot of boat for less buck and fuel economy the only answer is home building. The bigger you build the more money can be saved. On that 18 footer you can build turn key for half of what a comparable model you can buy and with alot more economy.
    Get up into the 26' class lobster boats you can build for a 1/3 of what you can buy for with better economy.

    I've often thought the engine companies were in bed with the boat manufacturers. Boats can be built stronger and lighter. The engineering and technology to do so has been around a longtime. Instead of boats being built lighter engine companies have built larger engines. Right now that type of boat is a custom build proposition which makes it an expensive proposition or a self build proposition.

    The best part is that you get what you want, not what is offered.
    For anybody that has minimal tools, can run a skil saw, and build from simple plans I'd highly recomend building if you want more bang for the buck and economy that will pay for the boat pretty quick. These boats can take it. They're darn near bullet proof with no nails, screws, or rivets.

    Smaller engines are not only more fuel effecient they are cheaper to maintain, take less of a tow vehicle, and less wear and tear on a tow vehicle.