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Thread: Inboard or Outboard... What's best?

  1. #1

    Default Inboard or Outboard... What's best?

    Looking for some opinions and facts on what the advantages and disadvantages between the two.
    Thank you

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    What type and size of boat? How much power do you need and what will you be using it for?
    Tennessee

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    Member bhollis's Avatar
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    Here are a few comparisons that occur to me:
    • inboards are generally more fuel efficient than outboards
    • higher risk of explosion with gas inboards than outboards
    • outboards can be tilted out of the water (avoids sea growth when boat left in water for extended periods)
    • generally easier to work on/replace outboards than inboards
    I'm sure others will chime in with additional pros and cons.
    Last edited by bhollis; 05-06-2007 at 14:44.

  4. #4

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    Need to define which 'inboards' your referring too. True inboards run a straight shaft out the bottom of the boat to which the prop is attached. Steering is accomplished by rudder(s.) The other 'inboard/outdrive' (or IO) runs the shaft out the transom, into an outdrive which pivots to direct prop thrust for steering.

  5. #5

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    Thanks for the replies,
    I would like to run a fishing charter someday. I've ran outboards for the last 5 years, but wanted to get some other opinions. I was thinking of a 22-24 boat. For inboards, I was referring to the I/O.
    I've been a teacher in the bush for 6 years and hope to get a job in S.E. teaching, and chartering during the summer.
    Any who, keep the replies coming.
    Thank you.

  6. #6

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    Well, there's already a bazillion folks running charter boats, and they're about to put the hammer down, in one form or another, but it's a nice dream.

    First off, your looking too small. When I moved here 10 years ago, a 27ft Sea Sport (single diesel IO) was about the standard boat. Now those boats are being sold off (you might look into that) and the guys with enough money are going large, and aluminum. Look towards 29-32ft, with various powerplants.

    IMHO, if your going to get clients to the hot spots, and back in a reasonable time frame, your gonna need speed. The only way to get speed is to turn lots of rpms.

    The new fangled electronic controlled diesels are complex, expensive, hard to service, and because of the rpms... little better than a gas inboard engine when it comes to longevity. Add in an outdrive, with the required gimbal/u-joint assembly, exhaust and driveshaft bellows, two 90 turns (compared to one in an outboard and zero in a true inboard) and it only gets worse.

    Then try to service that diesel, jammed under the rear deck of the boat.

    Nope, only one type of marine engine shines at high rpm running, and that's the outboard. They stay out of your way. They tilt up with any additional u-joints to worry about, or bellows to rip. Plus the other reasons already mentioned.

    While outboards can be serviced when on the water, it's not really a practical deal, there's little to nothing you can do under the cowl if one blows. Just fire up the kicker, or the other engine and go home. Call ahead to your marine engine store, and if they have the same model handy, it could be swapped out overnight. Then your back on the water making money.

    Again, just my opinion, based on running boats with all the configurations mentioned, and a couple that haven't been.

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    Moderator Paul H's Avatar
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    For smaller boats, ie under 30 feet, inboards are generally not a good idea, as they take up deck space, are generally heavier for given hp, with an i/o setup you have a big hole in the transom below the water line, and their is the fuel/vapor issue on board.

    With modern 4 stroke o/b's and direct inject 2 strokes, I think you'll get better mileage with an ob as well. I'm not sure what the price difference is when you factor in the drive system with an inboard. Most of the r&d in the marine power world for smaller boats is in the o/b's so you get modern state of the art engines.

    To me inboards only make sense when you're talking diesel as their are fuel savings, especially if you're talking about a displacement hull or a larger planing hull.

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    Member Sierra Hotel's Avatar
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    Quote Originally Posted by BrianW View Post

    The new fangled electronic controlled diesels are complex, expensive, hard to service, and because of the rpms... little better than a gas inboard engine when it comes to longevity.
    Brian, I agree that a diesel is probably not the most appropriate selection for charters in South Central due to the longer distances having to travel in a short period of time.

    However, I don't agree at all with your summary of of the newer electronically controlled diesels. The data indicated they are more reliable than the older mechanical enginers, they are certainly cleaner, and they are easier than ever to maintain with the electronic analysis aids available to engine technicians. And as far as longevity, the diesels are far more robust than gassers, and will outlast them usually 3 to one in terms of hours between overhauls.

    As far as getting under the deck to work on them - it's a PITA regardless of whether its a gasser or diesel.

    Cheers,

    SH

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    Well, let me toss this up for you to think about. I/O's do not have good fuel economy?
    I am running a 496 ci VP in my 24 foot Sea Sport, 375 hp. Loaded I guess my boat weighs 8,000 pounds. I cruise at close to 30 mph and burn approximately 2.5 -2.8 mg. I have one motor and outdrive to service, not two.
    Personally I cant stand fishing off the back of the boat with all those outboard motors hanging off the trasom. My dog house is only one foot high so it effects nothing and I have two gaint fish wells that I could not fill up if we limited out on everything.
    Negatives of my I/O? I hate winterizing it! Other than that I love it. And it is wayyy cheaper that buying a pair of outboards.
    And the wife is very happy with the heater and cabin defroster
    Tennessee

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    Member FISHFACE's Avatar
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    Quote Originally Posted by Sierra Hotel View Post
    Brian, I agree that a diesel is probably not the most appropriate selection for charters in South Central due to the longer distances having to travel in a short period of time.

    However, I don't agree at all with your summary of of the newer electronically controlled diesels. The data indicated they are more reliable than the older mechanical enginers, they are certainly cleaner, and they are easier than ever to maintain with the electronic analysis aids available to engine technicians. And as far as longevity, the diesels are far more robust than gassers, and will outlast them usually 3 to one in terms of hours between overhauls.

    As far as getting under the deck to work on them - it's a PITA regardless of whether its a gasser or diesel.

    Cheers,

    SH


    I run twin Volvo penta D-4's with out drives and I burn 13 gallons an hour @ 27knts on a 15,000 lbs boat when loaded with diesel. When i need anything done to those motors all my mechanic has to do is plug in this palm pilot device and it gives him the data. I used to have a 24' sea sport, but got rid of it becasue I wanted twin motors and having gas ( very flamable) can make for a bad situation on the water. The other benefit to having diesel is the torque and in ruff seas it's your freind. Someone also posted that outdrives have so many moving parts and cause for problems, but the lower unit of outboards aren't exactley the simplest either.all things have their pos and neg you just have to see your budget and your needs; speed, range, longevity. good luck
    Boatless

  11. #11

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    So doing the math, Fishface get's about 2.3mpg, compared to Snowwolfes 2.5-2.8mpg.

    Yet fishface is running a much bigger boat, and twins.

    Given my choice between those 2 boats, I'd not hesitate to forgo the sparkplug version.

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    Moderator Daveinthebush's Avatar
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    My Honda 90 get about 8-10 mpg. I won't buy anything but Honda.

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    Diesels absolutely get better economy however when I priced the least expensive diesel over my 496 ci it was an additional $15,000 above and beyond the cost of the 496!
    I would love to have a diesel I/O but $15,000 will buy a lot of gas! Even at $3 gallon that is 5,000 gallons. Enough to probably last me 8-10 years if I used the boat as much as I wanted to.
    Tennessee

  14. #14

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    Quote Originally Posted by Daveinthebush View Post
    My Honda 90 get about 8-10 mpg. I won't buy anything but Honda.
    That's some outstanding miles-per-gallon.

    It sounds remarkably like the 'gallons-per-hour' burn rate for my Suzuki 175hp 4 stroke.

    Hondas are nice, that's what I was running, until it broke.

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    Member AKBighorn's Avatar
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    Quote Originally Posted by Daveinthebush View Post
    My Honda 90 get about 8-10 mpg. I won't buy anything but Honda.

    Funny thing about that right there is that I was recently given an 8hp Honda for a kicker. Its a short shaft and I really need a long shaft. Long story short, Honda don't sell parts for it anymore and its a 1989 model. This is per our local full service Honda dealer and Honda Marine (corporate) on the east coast. I would have never thought the leader in the # of motors made in the entire world (so I read somewhere) would not sell parts after that time frame. Maybe they just aren't ment to last that long Either way I wouldn't buy one now.

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