Submersible, convertible, hydrofoil cat

Discussion in 'Boat Design' started by Infinitus, Oct 8, 2011.

  1. Infinitus
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    Infinitus Junior Member

    Battery and electric motor.
     
  2. Infinitus
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    Infinitus Junior Member


    Crew of one. Moi.
     
  3. Infinitus
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    Infinitus Junior Member

    That’s an interesting thought, although the idea does have a few obvious problems. I’m not sure it would be necessary, but I’m not ruling out anything at this stage.
     
  4. Infinitus
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    Infinitus Junior Member


    I understand your concerns. However, I would feel much safer if I am harder to spot, especially in high-risk areas and while exploring inland waterways in South America.

    I would, however, have a (removable) radar reflector during normal operation in low-risk areas (most areas) and I could even have visual reflectors which could easily be hidden if approached by potential foe.

    While moored the boat could be immersed by remote control when left, or even while inhabited with air supplied through a snorkel. How many petty thieves have diving gear?
     
  5. Infinitus
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    Infinitus Junior Member


    This is a concern, of course. An early idea I had to overcome is to enable the two outer hulls to expand longitudinally in order to increase their capacity for ballast such as to enable the craft to submerge without having to be permanently immense.

    Concerning the issue of weight and hydrofoils, I acknowledge your concern but will be keeping the size of the craft as small as possible. It will be more like a floating tent than a Fairline. Further, I am confident in obtaining high-strength and low-weight by optimally utilising geometry and materials and designing the craft purely according to the calculations, not according to any aesthetic ambition. It will not necessarily be designed to submerge frequently, but only when it has to. With that in mind more options are open for alternative ballast tank designs. This could include flexible tanks to aid in pushing the craft down.

    However, if ultimately the calculations show that the disadvantages would be unacceptable and insuperable then I would rethink the project.
     
  6. Infinitus
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    Infinitus Junior Member


    It is not a wind-up, I assure you. It may well remind you of something out of that publication, but what technology wasn't once the stuff of dreams and sci-fi?
     
  7. CatBuilder

    CatBuilder Previous Member

    Ok, inland waterways in South America do warrant a good security plan. Agreed.

    I bet I could get you to come up if I wanted to rob you though... that snorkel is your achilles heel. I could kill you while you were submerged, too. You should go through every scenario you can for your security plan.
     
  8. Infinitus
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    Infinitus Junior Member

    I'm yet to spend adequate time on security, because I first need to establish the design basics for the craft.

    Your comment on S. America is rather discombobulating. I much prefer being told that I am overreacting!

    If I do go with the idea of being submerged while moored, I would include a valve on the snorkel to prevent anything coming in, and possibly sensors to operate it. Air quality monitors in the cabin could alert me to high CO2/low oxygen. I would naturally have compressed air to breathe on standby.

    Defence measures could include high voltage electricity, flame throwers (of the sort used in S. Africa to counter car jackers), and many other options.
     
  9. upchurchmr
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    upchurchmr Senior Member

    Infinitus,

    Pick out one thing and make a calculation.

    You can't have a floating tent with a double aluminum hull capable of withstanding terrible storms, and an automotive engine and batteries and an electric motor all supported on hydrofoils at 40 kts and a retractable mast with out starting somewhere.

    So start with the automotive engine to drive the boat on hydrofoils. Assume a 30' boat to hold all the stuff you need - trimaran, weight might be 4000#???

    How much hydrofoil area would you need in immersed hydrofoil to support the boat?

    Lets just get this boat going before adding flame throwers. ( you must live in a terrible part of the UK to be so worried).
     
  10. Corley
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    Corley epoxy coated

    Wow, I love this thread I was feeling a bit down this morning and this thread has really cheered me up. Proceed with full camouflage and flame throwers good sir but dont forget the tank for sharks carrying fricking laser beams to take care of the survivors.
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    Walter Mitty lives, IMO.
     
  12. Corley
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    Corley epoxy coated

    Marc is right of course it is easy to be overly critical and negative. Its good to see people who aim high in their goals my advice to infinitus is define carefully what you want your craft to be and think on making a good mothership for the boat to reduce its range and endurance requirements. The challenges of that make it worthwhile in itself. Richard Bransons take on a fast submersible (designed by Graham Hawkes) is a good one and an engineering feat in itself that uses modern composites in an impressive way. Its sometimes good to reallocate our enthusiasm to something that is vaguely achievable.

    http://www.popularmechanics.com/technology/engineering/extreme-machines/questions-for-graham-hawkes-the-man-who-built-the-deep-flight-challenger-submersible
     
  13. Infinitus
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    Infinitus Junior Member


    I think that sounds like a good point to begin.

    I started this tread in order to gage opinion, stimulate thought, and for guidance toward direct information sources (primarily books) that go straight to the point with regard to the specific type of thing I am looking to achieve. So far so good, with the exception of the latter. So if anyone has any recommendations please feel free to post away. Of course I am aware of the available book lists but personal recommendations based on need are generally always helpful.

    The entire UK is a terrible place. I’ve already been attacked several times for no good reason (the last time I was walking home from the train station minding my own business when a group of yobs decided to make use of me for their night’s entertainment). Perhaps my perceptions – and experience – of universal violence is simply the manifestation of a negative thought process? Regardless, I’ve heard and read too many stories of lone travellers falling foul of aberrant thugs and villains, so I’ll certainly make an effort to stay as safe as possible.
     
  14. Infinitus
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    Infinitus Junior Member

    Thank you for the link. Very interesting.

    I'm thinking that diesel-electric would be the better power option for this project. The engine, mounted in the central section, would drive a generator which would power two or more electric motors mounted in steerable pods. This would eliminate the need for a long driveshaft and simplify the design in many ways.

    Or would the reduction in efficiency be too great for this to be a good idea, especially concerning the long distances I intend to cover?
     

  15. Corley
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    Corley epoxy coated

    Diesel electric is the most common method of propelling submarines. You have to consider the duty cycle of the electric motors your considering using they also have to be able to be water sealed to quite significant depths. They have reasonable endurance submerged and running on battery power. Ive seen some small submersibles that are relatively light but they are all battery driven.

    Your range aspirations seem counterproductive 13,000 miles means you'll be designing the craft around the fuel load to fully fly a craft like that on hydrofoils seems counterproductive better to leave the craft in displacement mode with slim hulls for reduced wavemaking resistance you can make a seaworthy craft that will not chew its fuel load excessively.

    Diesel motors are heavy that in itself increases the bulk of your submarine as you have to be able to have sufficient payload to carry the fuel they need plus have sufficient ballast tank capacity to raise and lower their own bulk.

    I remember seeing an interesting documentary where they were saying that the limit of a nuclear subs endurance was substantially linked to the amount of food that could be packed in for the crew.

    The Russians did some interesting work in adapting wing in ground effect vehicles into a heavy ground effect vehicle that moved heavy cargo at speed. They still suck a lot of juice but less than an aircraft and may be another means of achieving long distance travel as your mothership.

    http://www.vincelewis.net/ekranoplan.html
     
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