old dogs doing a new trick?

Discussion in 'Powerboats' started by 8knots, Aug 18, 2003.

  1. 8knots
    Joined: Feb 2002
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    Location: Wasilla Alaska

    8knots A little on the slow side

    I have a bit of a question for those of you in the slow boat mode. I am doodling around with one of my dream trawlers.(as seen in my pics in the gallery) I am trying to cram all that into 56' LOA But anyway stay tuned for revised drawings. Here is the question, I am in love with old DD 6-71's and I know in the old LCM8's (landing craft) they coupled these engines up inline with a falk transmission. This will solve the wing engine problem. I like the idea of having 2 identical old fashoned heavy engines. Am I a madman? Would a guy have a prayer of selling or insuring a new boat with old style (non EPA compliant engines)? I would like to hear from a veteran on the practical use of the falk transmissions.
    well I hope some body can shed some light on this.
    Thanks for your time!
    8Knots
     
  2. Willallison
    Joined: Oct 2001
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    Location: Australia

    Willallison Senior Member

    I can't profess to be a veteran, but as always - wanted or not - I have an opinion!:D
    You've touched on the age old question here to some extent - one engine or two....
    There are those that would argue that 90% of modern diesel engine failures are fuel related, so that having two engines is a far less effective insurance policy than having a good fuel cleaning and storage system.
    Proponents of the twin engine installation would argue that not only do you gain the reduncy of a 2nd engine, you also gain the manouverabilty of twin screws, the ability to run one engine at peak efficiency rather than a bigger engine slowly for improved fuel consumption and engine life,.... and so the lists go on.
    Your suggestion of two engines running through a single screw seems to me to somewhat defeat the advantages of having two engines. True, you still retain the redundancy and the ability to run on one (though how this would effect prop selection I don't know....), but you lose the redundancy of a second transmission and propellor. You also lose the manouverability. It may or may not be an issue, but single screw installations usually require deeper draft too.

    But more directly to the question of engine selection....
    I've often wondered why full displacement pleasure (and indeed commercial) craft are almost exclusively fitted with relatively high-revving, turbo-charged diesels. The answer, by all accounts, lies in the greater fuel efficiency they afford. And apparently the reality is that few commercial craft - let alone pleasure boats - rack up enough hours for the increased stress and subsequent wear to become an issue. ( As a sidebar, I recently had to do some work aboard a large - 30m or so - commercial tug. It had a pair of magnificent looking Blackstone straight-eight's. I was surprised to find that they too were turbocharged). So whilst it's true that big, slow-revving beasts like Gardners will run quite literally forever, their days - sadly - seem to be limited.....:(

    That was a fairly long-winded way of saying that they call it progress for a reason:p
     
  3. 8knots
    Joined: Feb 2002
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    Location: Wasilla Alaska

    8knots A little on the slow side

    Will
    As allways thanks for your insight! You are right on the issue of only one shaft and prop. My thinking is that 99 out of 100 the failure at sea will be in the engine not the drive train you are right allso in the fuel condition. but I believe diligent fuel filtering and a fuel polishing system will solve the problem! The fuel load split into 4 main tanks and the use of a day tank(I think) will cross out those negatives. The truth of this boat is that it will be for my own personel use here in Alaska (coastal cruising) She is really way to much boat hence the scale reduction. I am just too old fashoned I guess. I like the idea of "like my 48 chevy" you can tear down the entire vehicle with little more than 3 sockets and a pair of vise-grips. I am into the simplicity of it all! I can see myself motoring out 25nm's to Thumb cove and ride on the hook for the weekend! fuel use will be of little consequence for me! I know not the idel or practical use of a boat of her size. But when I get rich and all then I can sneak on around to the east coast with complete confidence! I know if I had any real smarts I would just go and put a new cat or Lugger in her and be done with it. Don't get me wrong, The morning rumblings in the harbor full of charter boats with those beautifull Cat 3412 TA's makes me all tingly inside! You are just not normal if you don't love things that have 8" wet exghaust and eat diesel.
    well enough ramble for now Thanks again!!!!
    8Knots
     
  4. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    The biggest problem with those old DD engines is the oil leaks. It is a Federal offense to discharge oil in the water. What are you planning on doing with the contaminated bilge water. I know a drip pan works, but these engines sling oil all over.
     
  5. Guest

    Guest Guest

    Amen on that! I have worked on 2 comercial boats with Detroits the boats were old and so were the engines My first 2 days on the MV TRADER I was handed a bale of diapers and told with a smile "get to it" Ha Ha! If I choose to really use the DD'S I would have them "completly overhauled" and have them painted blinding white so those leaks could be addressed right away! I think I will have no problem with the up-keep! I am a born tinkerer I want a sparkling engine room and a big warm wheelhouse! The galley can have hotplate on a piece if plywood for all I care! Mostly kidding of course! What do you do for a living Gonz? I see you are a big poster and very knowledgable!
    8Knots
     
  6. gonzo
    Joined: Aug 2002
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    Location: Milwaukee, WI

    gonzo Senior Member

    I build, design and repair boats. I have also worked in commercial fishing, sailing charters and offshore oil surveying. The new DD have different seals. They don't leak like the old ones. Maybe you should paint the engines black, wrap them on Depends TM, and change them when they need it:).
     
  7. Paul Browne
    Joined: Oct 2002
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    Location: Tampa, Florida

    Paul Browne Junior Member

    Hi Folks,

    This is my first post. Off to India now to see some real off-the-shelf old style diesels.

    http://www.satyajeet.com/de2.htm

    Let's see, two 10 kW one-lungers. That's 27 horses total. They drive two props at a screaming 1000 rpm. Neutral and reverse are through two Kitchen rudders, no marine gears. Engine weight 400 kg; that's 880 lbs....each!

    Cheers,

    Paul Browne
     
  8. Paul Browne
    Joined: Oct 2002
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    Location: Tampa, Florida

    Paul Browne Junior Member

    Oops. Belay that. It's 14 kW each, for 38 Clydesdale horses total :)
     
  9. duluthboats
    Joined: Mar 2002
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    Location: Minneapolis,MN, USA

    duluthboats Senior Dreamer

    Hi Paul,
    We want pictures, and get rid of the bull. ;)

    Gary :D
     
  10. Willallison
    Joined: Oct 2001
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    Location: Australia

    Willallison Senior Member

    bull...what bull:?:
     
  11. Paul Browne
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    Location: Tampa, Florida

    Paul Browne Junior Member

    I'd normally be insulted! A direct challenge like that is a call to a flame war! But in this case Gary is only refering to the bull on my website

    http://www.geocities.com/geezerboat

    By the way, I was trying to figure out this nifty forum here, all the bells and whistles like, and I notice that some of you mugs are senior members, some like me are junior members, and others are saddled with being mere "amateurs". I figure that's maybe because you don't have a professional position to put into your "user profile". So I figured maybe I would offer bonafide positions in Geezer Boatworks on a first come first served basis. Executive positions are offered first. President, Rear Admiral, Commodore, and many other attractive positions are still available. Just e mail me for prices! But hurry, this offer won't last long. :rolleyes:

    Cheers,
    Paul
    (Have to figure out this auto signature next.)
     
  12. duluthboats
    Joined: Mar 2002
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    Location: Minneapolis,MN, USA

    duluthboats Senior Dreamer

    Paul, I am very interested in the Kitchen rudder setup on the boat you spoke of. If you get pictures I know we all would like to see them.

    I see you got the jest of my comment about the bull. No flames on this forum. That thing dose get under your skin after about a min. :eek:

    8knots, sorry about the highjack.

    Gary :D
     
  13. Paul Browne
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    Paul Browne Junior Member

    I've never seen a Kitchen Rudder in the flesh. Learned about it from John Kohnen, who posted the following image on the yahoo boatdesign2 group. I don't suppose John would mind if I show it here. It's an old device, but extra nifty.

    Paul
     

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  14. duluthboats
    Joined: Mar 2002
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    Location: Minneapolis,MN, USA

    duluthboats Senior Dreamer


  15. Paul Browne
    Joined: Oct 2002
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    Paul Browne Junior Member

    Hope I didn't mislead you all. The boat I described as having two one-lung diesels was an imaginary craft. The engines are real enough, however. Wonder what they cost? Not much I bet. I just think the idea of using such heavy, slow, simple engines with direct drives and kitchen rudders is about the ultimate for a slow power boat. I think they are often hand started too. So if you used kerosene running lights, you could have an electricity-free boat. I'm not saying you'd keep the fillings in your teeth, mind you, but you could cross oceans with it. Which brings the discussion back to 8's slow boats and old diesels, so he shouldn't mind the diversion. I wonder how much they do shake. 880 lbs per engine! 5" bore, 6" stroke, cruising at 700 RPM!
     
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