Diesel Boat Heaters

Discussion in 'Powerboats' started by Boston, Apr 19, 2010.

  1. Boston

    Boston Previous Member

    interesting stuff as always Richard

    I didnt think the monotube boilers required a certificate that and I was shying away from the crazy high pressure system and more towards a lower pressure higher volume system
    I know I know it takes more room but that 200 hp 1000 psi engine of there's is not that efficient even at that high a pressure

    I was thinking of one of the old torpedo swash plate models that was originally designed to run on compressed air. Ok I had brief flashes of running the thing on compressed air but that thought only lasted until added up the weight of the tanks and volume of air even at high pressure I would need

    the oil issues I also have researched and yes the water has got to be spotless when it enters that boiler

    the idea of a stoker had not occurred to me though
    is it a requirement and is it really impossible to automate the system with any level of certainty
    now that is disappointing

    I must admit I have no clue what your saying about the dew point issue although the bit about scale in the boiler tubes I was aware of

    my engine room is 12x10x4 or almost 480 sq ft and at that there is another foot of framing bellow in which the diesel is planned to nestle with just enough clearance to drain the oil, so I figure I have about 4.5' of vertical space to play with on a boiler that is 36" tall and a steam engine that is less than that. Basically it kind looks like if I went with the big hi pressure unit from Reliable that its about the size of a auto engine block which it appears to be modeled after.

    I went on the steam forums for a while and soon realized that although steam has come a long way its still not really up to snuff for the fire and forget system that I was hoping for
    sounds like unfortunately you would tend to agree with that assessment

    cheers and no worries
    additional information pro or con is always good in my book


    oh and yes Mark
    I have that twisted need to revisit the entire logic process that concludes with why we do things the way we do these days specially when confronted with a whole new subject
    often by rethinking something from a blank slate new solutions to issues that have been long overlooked can be devised
    I tend to be reasonably good at that and you would be surprised how often I am talking with my friends still at university and I throw them some solution to a problem which has had them stumped for a while
    sometimes a fresh and dare I say ignorant view point is as valuable as any
  2. apex1

    apex1 Guest

    See my answers above in red!

    Hope I did not disappoint too much!

  3. WestVanHan
    Joined: Aug 2009
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    WestVanHan Not a Senior Member

    Boston: the problem with pellet stoves is they need 120VAC -use maybe 500 watts to start and about 300 continuous in order to run.
    I guess they could be converted to run on DC,or use a $$$ inverter

    Mark: One more reason I like the small Kubotas is they can be hand crank started.
  4. Boston

    Boston Previous Member

    some use that much juice of the ac variety but most have off the grid conversion packages available
    12 volt blowers and gas ignition

    it would work fine in a boat right up till you were rocking and rolling in something ugly and the pellets started falling out of the burner tray and down into the ash catch
    my bet is you would want to shut the thing off in anything serious

    I wouldn't use the Scottish type boiler, monotube all the way is what I've been looking at
  5. apex1

    apex1 Guest

    Too nervous, too hot the steam, too high the pressure (related), too much to adjust every moment, as there is no "reservoir". A full time job.

    And there is another restricion:

    the wood pellets do´nt have sufficient energy content to heat a steam boiler! At least not when the size of the boiler matters.
    A scottish boiler of 20m³ would be fine with that fuel though, at least to some extend.
  6. Boston

    Boston Previous Member

    crank that thing up to a certain speed and use a pressure relief valve to bypass the excess to the condenser when variations occur
    there are no seams in a monotube boiler and the diameter of the tube as well as its length is directly related to the pressure it will build
    ok as well as the number of BTU's you throw at it
    although flow rate and also has to do with it
    I have a friend at the local power plant and he operates three huge boilers
    very complex

    that and as I mentioned I kinda was leaning towards the old torpedo type engine

    at the moment I am more concerned with investigating the dynamic interaction of the axe bow configuration in a boat of this size with the typical sea state of that area

    food for another thread though as is this whole discussion about steam

    I like the idea of a diesel heater and so one of the heaters will be of this type
    another heater will likely be a pellet stove and third back up unit may or may not be waranted
    but multiple units is also a great idea

    once I determine the exact construction method and lay out then I can calculate the R values of various components and determine the BTU load at a given temp
    then I'll know if I want a third heater
  7. capt littlelegs
    Joined: Apr 2010
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    capt littlelegs New Member

    I generally agree with this, coal and wood stoves are the traditional method of heating a boat, they work well and are trouble free if installed properly. Keeping the wiring man enough to avoid volt drop with glowplug type burners is essential especially with 12 volt systems.

    I've heard very good reports of the new Hurrican mini furnace and knowing this more common pressure jet type technology very well would suggest this is also worth considering for smaller boats as being fully controllable, economic, reliable and an easily serviced wet system.

    The only issues I have with diesel pot burner types is that they run best at constant high levels which is not always what you want and are low efficiency so are wasteful on fuel, something that has to be considered these days.
  8. troy2000
    Joined: Nov 2009
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    troy2000 Senior Member

    Anything that burns fuel can be a killer without ventilation, and I don't use even tent heaters without it. But the small ones only need a few square inches.

    For my purposes anything more would be overkill, using up space and wasting fuel. Of course, if I ever decide to go sailing somewhere that has ice and snow on the ground, I'll sit down and come up with a plan B...:)
  9. capt littlelegs
    Joined: Apr 2010
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    Location: England

    capt littlelegs New Member

    I like steam engines. My father was a RN stoker mainly on an Atlantic convoy Corvette and from what I learnt about steam engines, their operation and maintenance from a boy onwards I have to agree with Apex, this is crude hands on technology needing constant attention and lots of standing space and more suited to constant running. Still might be possible though with more thought about the limitations and requirements.

    From the Flower Class Corvette Association.
    Flower Class Corvette - A Ship of 925 tons standard displacement when built, which increased to 1,180 tons due to modifications.
    Length - 205 feet overall, Beam - 33 feet, and maximum draft of 15 feet 6 inches at standard displacement.
    Two cylindrical boilers with a single shaft, vertical triple-expansion engine. The two boilers were oil fired, and had a capacity of 40 tons and a working steam pressure of 225lbs per sq/inch.
    The engine was reciprocal vertical 4-cylinder, triple-expansion which drove a single screw. Cylinder sizes were 18.5", 31.0" and 38.5" with a strike length of 30".
    Designed shaft horse-power was 2,750 at 185 rpm giving a maximum speedof 16/17 knots.
    Fuel consumption was 0.5 tons per hour at 10 kts and the bunkers held 230 tons of oil fuel.

    Not sure about the 4 cylinders mentioned!
  10. mark775

    mark775 Guest

    Thanks for the Zena link, Richard.
    Thanks for the WoodViking or whatever it was, Bos.
    You too, Han.
    Ditto, Littlelegs.
    I had no idea about steam - pehaps that's why we don't see 'em anymore!
    Bos, always open to alternatives - I keep thinking how to make fuel out of kelp. Seems one could "mow" some kelp and ferment or whatever on board for the next leg of your trip. I saw on Eco Channel, I think, a guy doing very well making fuel out of another alga. I'd sure like to be independant of others! Kelp grow close to a foot a day in the summer up here - I could mow the same bed every day for fuel! Why don't you research for me the technique, times, etc., for making fuel out of kelp - It will be interesting and I wouldn't have to do it!
  11. Boston

    Boston Previous Member

    Kelp is easy
    dry it out to <5% moisture content ignore the salt content and press it into a pellet in a simple pellet mill which can be either gas or elect


    just about any combustible works as long as its dry enough and can be shoved down the throat of the mill

    that site has outrageous prices but once again I've found this stuff for less than half the prices advertised

    thing to look at is the small mills and the dryers, dryers are just a heater with some goofy duct work and a blower to recirculate the heated air. A cloths dryer would work just fine as well from what I hear but you need to enlarge the capacity.

    DIY dryers can be made for a few hundred bucks and even the pellet mill is not that hard to DIY if your determined
    sea weed has a decent caloric value

    1 short ton = 907,184.74 grams at 4 calories/10 grams or 362,874 calories pr/ton or
    and this is the tricky part
    there is a difference between a Calorie and a calorie, one being in reference to food and the other being reference to heat
    there are 1000 heat calories in 1 food Calorie
    so we multiply this 362,874 by 1000 to find its heat value and thus its btu equivalent in fuel

    362,874,000 calories in one short ton of Kelp pellets vs 14,000,000 btu's in a short ton of hardwood pellets

    ~230 heat calories in a btu means 15,77,713 btu's in a short ton of Kelp pellets

    its was 252 calories in a btu

    oh well you figure it out but kelp works just as well as hardwood as a fuel source although its bound to be a pain in the *** to dry out

    combine that with this engine and a decent boiler set up and I was hoping to have a system that was relatively fire and forget
    oh well
    apparently its a tad more complex than that

    so much for sticking on subject
    oh well, I dont really care at all either way

    I killed a few weeks last winter drawing up that axial vector engine as a double expansion say 400 psi engine
    cant remember what I was thinking the HP or T was but it was fun to play with
  12. mark775

    mark775 Guest

  13. Boston

    Boston Previous Member

    well thats what I dreamed up the random question thread about cause as often as not its a thread I didn't start

    Im not sure you could squish much oil out of kelp but let me go see

    you might find this stuff interesting


    having dealt with a lot of scientists I would bet that if you simply tell them what your up to they will give you there process for making the fuel from Kelp start to finish
    I'm sure they would even avail themselves to answering a few questions along the way as well
    you could start with a small press and filter set up and then kinda play with it from there

    I like the idea by the way as its easier than using it as an external fuel source
    all except for removing the sodium that is

  14. Boston

    Boston Previous Member

  15. apex1

    apex1 Guest

    Biodiesel is NOT what we need in our engines!!!

    "FAME" (fatty acid methyl esther) is a gasket, sealant, hose and engine oil killer!

    But you can process Bio Diesel further into a useable fuel of highest quality.

    The same technique can process kelp into Diesel of about 58 - 60 cetane (that is much more than our fuel from the refinery).
    In fact this technology (a catalytic, pressureless depolymerisation) can process every raw material with a carbon content (that is ALL natural matter, and ALL plastic) into Diesel fuel.

    The drawback, it is a serious investment and cannot be installed on a yacht.
    A plant to process 500ltr. of fuel per hour is about 3,5 Million € investment.

    Than you can put in whatever you want (except metal and minerals) and get out between 35 and 90% of the input weight (depending on carbon content) in plain, best quality, sulphur free fuel. Calculated in % of dry (waterfree) matter.

    Smaller units are possible, but not feasible. A 50ltr. / hr plant is NOT one tenth of the building cost, more like 20%.

    So get some 3,5 mio € out of your wallet and invest in such a plant! Assuming the input material is for free (it should be waste anyway), you can make a hell of a good profit. But for our, yacht related, business forget about it.

    Sorry for disappointing again.

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