Potentially Stupid Concept (Houseboat?/Landingcraft?)

Discussion in 'Boat Design' started by LLL003, Dec 13, 2019.

  1. LLL003
    Joined: Dec 2019
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    Location: Cardiff, Wales

    LLL003 New Member

    Long story short I'd like to build myself a boat at some point, and I had a somewhat crazy idea I'd love to run past someone who knows what they're on about.

    The gist of it is a ~80 ft vessel, steel hull, that's a live aboard houseboat for myself and my family, a workshop for myself, and can beach itself to offload a vehicle / cargo (unfortunately, not the camero shown below!)

    I'd love for it to be diesel electric with useful range on pure electric, and enough solar to meet the full hotel load and recharge the propulsion batteries a bit. I intend to run the generators off of vegetable oil to keep the running costs down a bit too, so hopefully this will be about as green as you can get without sails. Ideally this would have range to cross the Atlantic (obvs on diesel not battery!). If I only had to run the generators say 60% of the time while cruising that would be a win in my book.

    Ideally, I'd like to get this designed professionally, and do a good portion of the work myself for monies sake.

    As for why the workshop and the landing craft-esc nature, the line of work I'm hoping to get into would greatly benefit from a workshop with mill,lathe, etc etc, and a way to quickly and easily move heavy wheeled items ashore, both to a concrete slipway or a beach in the middle of nowhere. If i could say more I would!

    I've attached a photo, take this for the sketch on the back of a napkin that it is! I intend to get it professionally designed when the time comes, but I'd love some early conceptual feedback.

    Thanks! - Thomas

    [​IMG]
    [​IMG]
     
  2. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    The 3/8" has got me intrigued !
     
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  3. JSL
    Joined: Nov 2012
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    JSL Senior Member

    interesting project. Kind of skinny Probably okay for protected waters. Your Camaro is in the 'spray' zone so expect it to corrode quickly
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    How does running generators with vegetable oil save money ?
     
  5. bajansailor
    Joined: Oct 2007
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    Location: Barbados

    bajansailor Marine Surveyor

    Bear in mind that the upper limit for operating vessels without professional crew (ie crew that have qualifications) is 24 metres (approx 80') loadline length.
    Have you got a Million (or two or three even) spare to throw into this building project? Even if you do some of the work yourself the cost will still most probably be twice or three times your anticipated cost of construction.
    A barge shaped hull form like the one shown in your sketch is not going to be very efficient in terms of miles per gallon (or more likely gallons per mile) - no matter if you are using diesel or vegetable oil. And transatlantic range is probably not very realistic.
    It would probably be a lot cheaper to buy something secondhand, and then adapt it to suit?
    There are a lot of 'little' RO/RO vessels trundling around - here is a nice 24 metre RO/RO that was last heard of in the BVI's last year.
    Vessel details for: PRIME MOVER (Cargo) - MMSI 503457300, Call Sign 24867QB Registered in Australia | AIS Marine Traffic https://www.marinetraffic.com/en/ais/details/ships/shipid:695519/mmsi:503457300/imo:0/vessel:pRIME%20MOVER
     
  6. Mr Efficiency
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    Mr Efficiency Senior Member

    A bit of a haul from Darwin to the UK with that barge !
     
  7. bajansailor
    Joined: Oct 2007
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    bajansailor Marine Surveyor

    For sure! I very much doubt that she drove halfway around the world on her own bottom, hence more likely she was shipped.
    Marinetraffic has not heard from her for over a year now, so I wonder what has happened to her?
     
  8. LLL003
    Joined: Dec 2019
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    Location: Cardiff, Wales

    LLL003 New Member

    Thank you for your replies!

    Its critically important! :D


    From my research, running a generator on used vegetable oil would use ~16% more fuel by volume for a given output power, however used vegetable oil is (in my area in 100 micron filtered) only 33% the cost, so overall its about 40% the fuel costs. Doesn't play well with common rail engines though from my (admittedly limited) knowledge. The main disadvantage is unreliable quality requiring you to have the ability to filter and treat the fuel on board, and having it delivered to a marina is a lot less convenient than filling up from a pump.


    The hull is more what was quick and easy to throw into sketchup to get basic dimensions, I plan on it being significantly less blocky, although the bow is somewhat constricted by the ramp, so I'm never expecting it to be particularly fast or efficient.


    Not quite yet, some day though! My "backup plan" is to go with secondhand and adapt it, although it would mean a lot less compromises if from scratch, so that's what I'm aiming for!

    Thanks all!
     
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  9. Quan Kwota Quinn
    Joined: Jan 2020
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    Location: Oregon, United States

    Quan Kwota Quinn New Member

    I think
    Potentially Stupid Concept
    could be the default title for a majority of threads on here. And to be clear, I'm very happy about that. This is the most imaginative website I visit!
     
  10. gonzo
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    gonzo Senior Member

    What is the budget? Diesel electric will cost a huge amount more with little gain unless you run the engines over 2000 hours a year. Barges are terrible in open seas, but can be made to work. However, if you intend to carry a large car, have sufficient living space and load cargo, the boat is way too small.
     
  11. Ilan Voyager
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    Ilan Voyager Senior Member

    I spent all my working life as naval engineer and boat builder to make it simple, so I'm in awe while people search complication. Steel with alu superstructure on a 80 feet yacht, electric diesel, a few tons of batteries, a car on the bow and a folding ramp...I guess that this boat if built will be named "Regardless of Cost".
    First the car...a lot of fluvial boats have cars on the deck and there is no need of a ramp. Make a search about barge river boats. If sailing on sea to some paradise tropical place, forget it. But even if you plan to stay in the UK coasts and maybe the EU, the last nuisance you want is a rusting car on the bow. You'll have enough work in fixing the clogged diesel engines. Foldable electric bicycles with big 36V 20 ah bats, or a small scooter, gas or electric are as good for a yacht. It's far less costly to rent a car, if really needed, or to hire a taxi arrived at destination than to try to carry a car on a yacht.
    Second the electric diesel with big bats on a yacht. Furthermore usable with vegetable oil...That will cost and weight a lot of pounds, and at my knowledge, except some very simple stationary working diesels, all the yacht diesel marine engines I know will be fried if vegetable oil is used (pun intended).
    Third...No I stop here...Oh, just a question; how many millions pounds have you for the project? Because that's going to cost far more than a leg and a arm, with the custom made vegetable oil diesel electric and the tons of LiPo batteries. I guess you have not, as people with a few millions pounds hire a naval architect.
     
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  12. sharpii2
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    sharpii2 Senior Member

    The first thing to go in a storm will be the car. It's 3 to 4 thousand pounds will not only cause a more exaggerated pitch but the exaggerated pitch it does cause is likely to totally immerse the car and maybe sweep it clean off. Or it will ram it aft (where it should be anyway). Most landing-craft keep their vehicles as close to amidship as possible. The vehicles only come up to the ramp after the craft has been beached. This is especially true if the vehicles are a large proportion of the vessel's weight. So the car is going to have to live inside the vessel.

    Another thing you should consider is the total weight of your vessel. You are going to need about 4 to 5 hp per ton. In cruising mode, you may actually use half to two thirds this amount. But this assumes you are willing to cruise at an S/L rate of considerably less than 1.0. With a 70 ft LWL, this would be about
    8.3 kts. So, if your willing to cruise at say 6 kts, you may use only 2.0 hp per ton. But it looks like you have a lot of tons here. You may be able to get as much as 60 ton/miles per gallon of diesel if you use direct-drive and cruise at the slower speed. If you go diesel/electric, you will get considerably less than that, maybe about 85%. And, of course, this assumes a reasonably efficient hull shape. So, if all this is true, you will get about 60 ton/miles per gallon of diesel under the best circumstances. Under stormy conditions or with a strong headwind, you will get as little as 40 or even 30. Keeping these realities in mind, you will probably find that you will be driving a diesel tanker if you want realistic ocean crossing capability. Keep in mind that a healthy portion of your vessel's over-all carrying capacity must be reserved for fuel if long passages between refueling are to be considered. Assuming that the overall weight of your vessel is, say 60 tons including half-full fuel tanks, you will need at least: (60 tons * 3,000 miles * 1.15)/((60+30/2)ton/miles per gallon) or 4,600 gallons. This 4,600 gallons is going to weigh about 15 metric tons and is going to require about 231 cubic feet of tankage.

    Another issue to consider is stability. With a motor vessel, you can have both too little and too much stability in a seaway. You should have enough to recover from a roll of at least 60 degrees. But if you have too much, your vessel will have a snap roll which will not only be uncomfortable for the people on board but also dangerous for the cargo. It can be thrown about or caused to slide or roll from side to side. Items and even people can be catapulted from the deck. So a very careful balance between initial stability and ultimate stability must be maintained at all load levels, including tanks empty. This can be difficult to achieve. It is my opinion that seagoing motor vessels are harder to design than seagoing sailing ones for this reason.
     
  13. Ilan Voyager
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    Ilan Voyager Senior Member

    Reading again this thread I apologize but my stupidly ironic words, but over the years I got fed up by the regardless of cost, the under-cheap with inferior materials, the high tech by no technician, and other ill fated projects. Sharpii2 made wise remarks. But I want to add an hopeful note.
    LLL003's houseboat is perfectly feasible at reasonable price comparable to a house in UK, where real state is awfully expensive, if kept simple ie modest diesel engines, moderate speed, steel hull but very good comfort, nice habitability, and enough batteries to cover the house needs during 2 or 3 days.
    It's possible to make it able of coastal cruises by good weather at sea with a reasonable seaworthiness along UK but also to be a river boat if kept in the width of a European class A barge ie less than 5 meters and less of 1.80 meter draft. That opens thousands of kilometers of waterways in Europe and UK so this boat able to cross safely the Channel can go to the Black Sea by the Rhine and Danube rivers, and to the Mediterranean Sea by the Seine and the Rhone rivers. After it can go long around the French and Italian coast with its myriad of old harbors.
    [​IMG]
     
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  14. DogCavalry
    Joined: Sep 2019
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    DogCavalry Senior Member

    "Environmental" options are an increasingly popular fad. But the overall environmental impact is usually much worse for the environment than keeping it simple. Solar panels aren't made of unicorn fur. They have a heavy environment cost which can only be returned in sunny climes. Most locations they are used they are bad for the earth. Vegetable oil, unless recycled from the chip shop, is much worse than regular diesel. Diesel electric is bad. Unless the masses of electrical equipment involved can be made from unicorn fur.

    Bottom line, leave all that stuff in the field with the unicorn, go with solid standard practice. The ice caps will thank you.
     
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  15. Heimfried
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    Heimfried Senior Member

    That is simply not true (i don't mean the "unicorn"). But this opinion is "on the market" and much loved by the guys who like combustion engines, especially large and powerful combustion engines.
     
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