If the engine doesn't start, it drowns?

Discussion in 'Inboards' started by CaptainAB, May 8, 2010.

  1. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    adiabatic diesel is close to a solution
  2. murdomack
    Joined: Jun 2007
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    Location: Glasgow

    murdomack New Member

    Your father was right, it has happened to me a few times in the past. When I re-engined, five years ago, the installation drawings asked for 1" inlet diameter. This meant that I doubled the size of my previous intake, seacock, filter, pipes etc. I have not had a blockage since, so I assume that the previous installation was inadequate.

    As someone above has said, if it is done properly, alarmed and easily accessible it should give little trouble.

    Can you run your dry exhaust overboard without compromising water tanks, fuel tanks or cabin accomodation? You couldn't on my boat.
  3. Brent Swain
    Joined: Mar 2002
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    Brent Swain Member

    No problem . I run the dry exhaust out the transom. It is wrapped in fibreglass house insulation ,then 3 inch muffler tape, then siliconed, for an overall diameter of 4 inches. Cool as a cucumber outside ,after days of motoring in the tropics.
    No matter how well you do a saltwater intake , there is no insurance against something plugging it from outside, in the middle of the night. Dry exhaust and keel cooling is far more reliable , period , no matter how you do it.
  4. apex1

    apex1 Guest

    W R O N G !

    ALL major superyacht and megayacht builders prefer wet exhaust! Why?

    Keel coolers are vulnerable.
    Dry stacks like to burn. (your cucumber may be cool, the stack isn´t)
    Engines gain from wet exh. elbows.
    A proper setup of raw water inlets is on both sides of the hull. (yes, two ways to fail, but none to clog)

    And so on.....

    If a keel cooler fails (and they do), you are completely fu(ked. When a inlet is clogged, you have a chance.

    This discussion...

    ..no I said that twice already.


    (no regards)
  5. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    ....keel coolers on steel boats are NOT exposed to the world, they are incorporated in the keel, double section, exposed tube type, keel coolers are what Apex is referring to, and yes they are very vulnerable to damage. Integrated type design allow coolant to run freely in a very large area of the underwater sections of the steel boat, in fact they are so efficient that the thermostat will be working to regulate, as sea water temp is quite stable and water cooling compared to air cooling is 16 times better.
  6. apex1

    apex1 Guest


    integrated keel cooling is a perfect solution.

    Unfortunately restricted to lower power ranges in all sizes of vessels. Just because the surface of the disposed steel is nearly never sufficient to provide enough area due to conductivity. (the lack of)
    In Aluminium boats the situation is far better, but still not always sufficient.
    A 400hp engine requires some 20m² of skin cooling area on a steel vessel, still 6m² in Al. That is "net" cooling area! The painting has to be taken into calculation!!!
    The raw water flow / coolant flow of such engine is about 1 liter per hp/min.
    When the keel cooler breaks, you have 400 litre of raw water going through your engine, every minute. In a environment that cannot cope with it. ANd you have ZERO chance to do anything (except sailing).

    Coolers outside of a hull are just a idiotic idea.

    Brent mentioned his Father being a "steam boater", he did not mention the cubic miles of raw water every steamer pumped through his systems every day!
    A ash ejector pumped 5 - 8 cubic meter of raw water a minute! A condenser the same and more. All generators, circulation pumps, injectors, rudder machines, and so on had to be directly or indirectly water cooled. RAW water cooled. The raw water inlets on a 3000 tonnes freighter in the 40 ies have been almost of the size of a barn door, accumulated. Did they fail? Yes, some. Do we fail? Yes all.

    And this insane ***** fears raw water in a ship................

  7. Landlubber
    Joined: Jun 2007
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    Landlubber Senior Member

    "Do we fail? Yes all."

    ...and this of course brings us all back to earth...KISS Keep It Simple Stupid.

    ...seems we go around in circles Apex on this web site...some believe you, some do not, but we all get back to BASICS no matter what in the end, and , of course, you are right.
  8. tunnels

    tunnels Previous Member

    Check out this site !

    I have had this info for a while and just found the printed copy i had filed away .
    This has the basics and a little more besides , worth storing away for that rainyday and wanting something to read !!.

    I have info about mufflers as well just need to keep hunting .
    All to do with size of motors x hp x muffler sizes x shapes and lengths of pipes etc etc its what i have worked to over the years and never ever had a problem of any sort :D
  9. apex1

    apex1 Guest

    Ja, ja tunnels, we all have some info.

    Experience is how the info gets into life, everyday life. Or worse, life at sea. Everyday life at sea, over month´s and years.... at sea.


    I know that you know.
    But believing ME is not the issue, facts are speaking for themselves, no matter who provides them. (I know I am not everyones darling, and I can stand that very well)

  10. mark775

    mark775 Guest

    Brent Swain, you don't know enuf about boats to have "days of motoring" (as you put it). Don't lie. My most recent deckhand's most recent slickers have more experience than you and you shud consider taking notes rather than trying to salvage your ego.

    Tunny, Re: 9. Don't over crank your engine.
    When you over crank an engine that
    doesn't start, (when bleeding the fuel
    system for example), there is no exhaust
    pressure to empty the muffler. Water fi lls
    the muffl er and can then back up the
    exhaust hose into the engine.
    If you must crank your engine for
    more than one minute at a time, close the
    seacock and remove the impeller from
    your raw water pump until the engine can
    be started. Stop the engine immediately,
    replace the impeller. Open the seacock.

    -I have known these guys since they started. They build a fine genset.
    The founder's son, Jeff Johnson as I recall his name, once told me "I know these things...I am a real engineer...I went to school" right before he suggested glassing 4" "bulbs" into the bottom of an Egg Harbor yacht to accomodate engines he was trying to sell ("It's done all the time"). Real-life boat experience or common sense may not be the strongest suit.
    If one runs the to-be-injected water to available height (a foot, or more, above injection point), tap into this line before it gets to the top and let 1/3 of the water drain over the side of the boat but where it can be seen from the helm, that will accomodate all the water flow that can be generated by cranking. Don't forget the vented loop. The exhaust GRP and hose don't need all of the water that the engine needs to cool - it'll be fine.
    To know if one has lost water flow, immediately, an external sensor on the exhaust mixing elbow shud be installed. Set to maybe 140°F., within an instant, as quick as any other type sensor and more reliably, one will know when waterflow is reduced. Paddlewheel sensors have proven unreliable - lever arm sensors may be good but it seems that they wud restrict flow and I trust a temp alarm clamped right on the elbow.
    Also, Lugger sells that Gen-Sep thing, which you can simply do yourself by glassing Green Thread pipe into the bottom of the waterlift and losing water seperate from air. I did this on a yacht twenty years ago and all one can still hear is "hush".
  11. Submarine Tom

    Submarine Tom Previous Member


    The original poster has been gone since page one!

    No one would have noticed that, you're too busy arguing like school children trying so desperately to be right.

    Good luck with that.

    Joined: Oct 2002
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    Location: Conn in summers , Ortona FL in winter , with big d

    FAST FRED Senior Member

    "ALL major superyacht and megayacht builders prefer wet exhaust! Why?"

    The swells expect to use the top of the boat for lolling about, so sticking the exhaust out in the transom , heat , stench , smoke and noise works better on a charter bucket.

    For folks with dry stacks the use of a "hospital critical" style muffler will make that 500 hp diesel sound like a VW. But it weighs 200+ lbs .

  13. tunnels

    tunnels Previous Member

    The boat i worked on had 2 x 3000 hp and all the exhausts came out under the hull under the water and it was so quiet Each muffler was big enough for a person to crawl inside the pipes. The big pipe near the top was for the main engine ,the smaller one was for the gen set the pipe flang at the bottom was where it connected to the pipe that went out through the hull bottom !.

    Attached Files:

  14. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    So if the gen set was running and the main engine wasn't the gen set exhaust could blow back up the main engine pipe?

    Not the first megayacht builder to fall for that one.

    Was it German or Dutch built?
    anybody else is just a wanna be

  15. mark775

    mark775 Guest

    "Was it German or Dutch built?
    anybody else is just a wanna be"
    - I have been involved with some fine boats built by Delta Marine and seen less-than-perfection come from Germany. Great stuff from Australia/New Zealand, as well. Tho, on average, the best come from Germany, you and Richard are stretching that sentiment quite a bit! Any good yard is striving to improve and good and bad can come from some of the best (even my hometown Delta, I'm embarrased to say, has dabbled in "EuroStyle" and sometimes tends to use more putty than structural elements that can withstand vile weather) I spent a winter on the Abeking day-sailer Extra Beat http://www.abeking.com/Extra-Beat.39.0.html?&L=1 (parts of steering gear, Swagelok lines, shafting, some keel work, sound insulation in engine room, roller furler, all hydraulics and misc. have my signature) and there were many mistakes in construction (tho, I will add - if I were to like the soul of a big sail boat...this wud be it)
    Also, Subperson, there is nothing desperate to what I am saying. I was trying to teach how to do this. If that is unwelcome, I will stop - in the meantime, lest someone take it as reasonable, nonsense such as your last posted and that of BrentSwain needs to be pointed out.
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