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Thread: Gas vs. Diesel

  1. #1
    Member AK Tubes's Avatar
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    Default Gas vs. Diesel

    I'm just learning about "ocean" boats - in the mindset of considering purchase anyway.

    I know diesels are typically quite a bit more expensive, but at what point (boat size) does one have to say gas engines burn too much and go too slow? A friend of mine bought a 38' Uniflite with gas engines and IMHO, it's a pig. Very comfortable, but only 14kts and 28gph!!! Should one expect THAT much more performance from a diesel to justify the cost?

  2. #2
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    Default

    Well, thats a good question. I suspect the diesels really start paying for themself when you are looking at 30 foot boats and larger with twin motors.
    On a smaller, newer boat that has a EFI gas motor then it is a different call at together and very debatable as to which way to go.
    For example, for my SeaSport the 8.1 EFI motor was a $5k option. To go to the smallest diesel it was ANOTHER $12k above that. I average 2.2-2.4 mpg when cruising at 25 mph. I am sure a diesel would double my fuel economy but even running 100 hours a year how long would the payback be? Granted the range is much greater with the diesel but then you need to add another gas tank if you have a gas kicker.
    Only the boater who buys the boat can decide if the additional cost of the diesel is worth it to them.
    Good luck in your decision.
    Tennessee

  3. #3

    Default gas vs. diesel

    I hate to say it, but if you really have to ask how much it costs.....you can't afford it. Fuel is only a part of the total expense of owning an ocean boat.
    If you are worried about fuel get an 18 ft with a 50 hp Honda.

  4. #4

    Default

    More info is needed. But going with the 38' Uniflite example, then diesels would be the way to go.

    It really depends on if your looking for a planing boat, a displacement boat, or the worst of the bunch (like the Uniflite) a semi-planing boat.

  5. #5

    Default

    There wasnt a choice offered on my boat, they use diesel engines only.

    Having them make it twin diesels added quite a bit more. For me I like the saftey of a diesel.

    Keep in mind when you are buying a decent sized boat another 200k is just a small drop in the bucket.

    Stabalizers
    larger fuel tanks
    interior choices
    electronics
    ect....

    It adds up fast

  6. #6

    Default Fuel Burn

    Ah...fuel burn. Well, I ran my 50 hp Honda to Pigot Pt and back, and did some trolling. I guess it might have sucked up 2 gallons.
    How did you diesel guys do?

  7. #7
    Moderator Paul H's Avatar
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    Default

    As others said, it depends on boat size, and isn't a cut and dried comparison. Diesels are typically quite a bit heavier than a comparable gas engine, so you're burning extra fuel to push the heavier engine. If engine weight is a relatively large percentage of boat weight, this is more of a factor.

    As far as factoring in fuel consumption to boating expenses, it is a considerable expense. It really hits you if you look at older boats. It's tempting to see an ocean capable boat for under $20k, which seems pretty affordable. But if you're burning 60-100 gallons every time out, that bargain isn't. If you look at some of fairly popular aluminum cabin cruisers in the 22-24 foot boats with a single 115-150 you can cover alot of ground burning 1/2 that much fuel. I only burned 12 gallons running from Whittier to Disk Island this weekend, and after hitting a few fishing spots and detouring to blackstone glacier on the way back, I burned 35 gallons for the weekend.

  8. #8
    Member Sierra Hotel's Avatar
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    Default The numbers say go OB . . .

    Diesels seldom make economic sense on recreational boats due to the higher acquisition and maintenance costs, and we don't put the hours on the engines to make the economics level out. If you're running a charter, you can make the economics work - but only on the larger boats. Cummins-Mercruiser has been woring hard to introduce smaller diesel engines into the recreational marketplace, but I don't think they're having much success here in cold-water country. The single greatest cost in the ownership of any piece of equipment over the life cycle of that equipment is fuel. If you run only 200 hours per year (that's probably an avid boater out 2-3 days every week), the cost delta in fuel savings will not be offset by the initial capital expense (buying the more expensive diesel powered boat) and the significantly higher maintenance costs (an OB engine might use 4 qts of oil per change, a 5.9 liter Cummins B-series uses 6 GALLONS of oil per change, with about the same oil change intervals).

    OB ENGINE ANALYSIS
    Assuming 10 gph, 200 hours per year, a 10 year life cycle for the engines, $2.99 fuel (escalating 1% per year), you will spend $65,402 on fuel over that 10 year span. (Man, maybe I should sell the boat now!).

    Oil changes will run you less than $500 over that 10 year span, compared to more than $1,500 for the diesel.

    Initial acquisition costs for 230 hp is about $12,000 for Yamahas.

    DIESEL ENGINE ANALYSIS
    Assuming 8 gph (@2500 rpm), 200 hours per year, a 20 year life cycle for the boat/engines, $2.84 fuel (escalating 1% per year), you will spend $49,697 for fuel over the same 10 years.

    Initial acquisition cost for a single Cummins QSB 5.9 230 engine (new) with a ZF tranmission and outdrive is in the neighborhood of $50,000, and you don't have a backup engine.

    Not to mention that the diesels generally require a bigger boat, driving the costs up further.


    I'm a big believer in the diesels, but could never justify the expense for my personal boat.

    SH

  9. #9
    Member Sobie2's Avatar
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    Default

    Well for smaller boats (say boats which would have a single volvo diesel or gas duoprop setup) it comes down to this... do you want to pay more now or later? The premium for a diesel rig is up front at purchase time which can be rolled into a loan. If you opt for the 496HO gas duoprop you pay more at the pump everytime you go out (and more frequently). Personally I know many people who have bought a new boat and then had to nickle and dime it everytime they go out because they didn't budget for fuel.

    Here is what I am planning on my 2 unifilites: my 27' sportfish flybridge has a single 454 duoprop and won't be repowered with a diesel, but my 23' which is in awesome shape and was owned by my grandfather which has an old omc cobrajet sterndrive will be repowered with a volvo d3 190 duoprop.

    Sobie2

  10. #10
    Member AK Tubes's Avatar
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    Default Not worried about anything

    Quote Originally Posted by Ak Steve View Post
    I hate to say it, but if you really have to ask how much it costs.....you can't afford it. Fuel is only a part of the total expense of owning an ocean boat.
    If you are worried about fuel get an 18 ft with a 50 hp Honda.
    I'm not worried about "the expense of an ocean boat." I just wanted some ideas other than my normal opinion offers and thanks to everyone who has had something to say. When I buy one, it wil be bought with cash, in full. The "expense" will be enjoying it. I can handle that just fine...

    Why is it in every post I've read where cost is discussed, there is always someone out there assuming that because someone is trying to put finishing touches on a plan or idea and polls the forum for ideas, that they can't afford it?

  11. #11
    Member AKBassking's Avatar
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    Cool Just Because

    Quote Originally Posted by AK Tubes View Post
    Why is it in every post I've read where cost is discussed, there is always someone out there assuming that because someone is trying to put finishing touches on a plan or idea and polls the forum for ideas, that they can't afford it?
    Because most of us can't afford it, but we do it anyway!

    It is the Alaskan way!

    ALASKAN SEA-DUCTION
    1988 M/Y Camargue YachtFisher
    MMSI# 338131469
    Blog: http://alaskanseaduction.blogspot.com/

  12. #12

    Default if money isn't the issue

    Then range is, as it was for me. A boat powered with a single gas 454 just didn't have the range I wanted. Make sure your boat has it. Montague is a long way away.

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