Is my hull shape decent?

Discussion in 'Boat Design' started by stonedpirate, Feb 7, 2012.

  1. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member

    heres a dude swimming alone in the middle of the atlantic from a 14 foot boat: http://www.youtube.com/watch?v=8vbAWrfUPBk

    The way i see it, all oceans have been crossed by 10 footers.

    That dunlop guy crossed the pacific in a 10 footer. That old dude crossed the atlantic in an 8 footer, indian was crossed in a 9 footer.

    Someone just has to do all of them for the record to be broken.

    Clearly, it is possible.

    Not to mention serge going all the way round in 12 foot.

    Its the almost impossible mission.

    As for liferafts and holed boats.

    Basically, the volume of my boat is so small, that a hole can sink me in under a minute.

    The boat is a life boat. Do you need a lifeboat for your lifeboat?

    As for visibility, radar transmitter and masthead light. If i get hit, i get hit, just like all the other 30 footers that get hit every year.
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    There's nothing in any of this worth dying for. Hey stonedpirate, get in touch with Kay Cottee and see what she says, the fact she is still alive is a miracle at sea.
     
  3. TrustedShips
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    TrustedShips Mr.

    If that is your approach, then why bother designing the boat at all. The very purpose of design is to ensure ensure that it is at least safe to travel on. Speed, luxury, come later.

    Yes, I would recommend a life raft on a life raft, since you are on a mission to circumscribe the globe and not a mission to get drowned. I am talking about an inflatable life raft.

    Also see if you can provide some kind of subdivision or double hull.

    An since you chose to ignore the link, let me quote from there:

    "Steven Callahan (born in 1952) is an American author, naval architect, inventor, and sailor most notable for having survived for 76 days adrift on the Atlantic Ocean in a liferaft.... A naval architect by training, Callahan has designed and built boats, taught design, lived aboard, raced, and cruised boats of all kinds.... Callahan departed Newport, on a 6.5 meter sloop he designed and built himself, singlehandedly sailed the boat to Bermuda, and continued the voyage to England.... In a growing gale, seven days out, his vessel was badly holed by an unknown object at night storm, and became swamped, although it did not sink outright due to watertight compartments Callahan had designed into the boat.... Unable to stay aboard "Napoleon Solo" due to it being full of water and getting overwhelmed by breaking seas, he escaped into a six-person Avon inflatable life raft, measuring about six feet across. He stood off in the raft, but managed to get back aboard several times to dive below and retrieve a piece of cushion, a sleeping bag, and an emergency kit containing, among other things, some food, navigation charts, a short spear gun, flares, torch, solar stills for producing rainwater and a copy of Sea Survival, a survival manual written by Dougal Robertson, a fellow ocean survivor.... No rescue was initiated from Callahan's use of an EPIRB (Emergency Position Indicating Radio Beacon) and many flares. EPIRBs were not monitored by satellites at the time, and he was in too empty a part of the ocean to be heard by aircraft. Ships did not spot his flares. While adrift, he spotted nine ships, most in the two sea lanes he crossed, but from the beginning, Callahan knew that he could not rely upon rescue but instead must, for an undetermined time, rely upon himself and maintaining a shipboard routine for survival. He routinely exercised, navigated, prioritized problems, made repairs, fished, improved systems, and built food and water stocks for emergencies.... On his 76th day afloat in the raft, fishermen picked him up just offshore, drawn to him by birds hovering over the raft, which were attracted by the ecosystem that had developed around it. During the ordeal, he faced sharks, raft punctures, equipment deterioration, physical deterioration, and mental stress."

    Callahan was a proper Naval Architect, he had provided subdivision for his boat, he was carrying life raft and flares too. Still he just drifted for 76 days helplessly.

    Also you may like to see this:
    See this vid at 00:51
    http://www.youtube.com/watch?v=nvh2hCxUvJA&feature=related

    This other boat will be somewhere between 10-15 m long in moderately rough weather:
    http://www.youtube.com/watch?v=hAOc0SSyE3E

    and this, people trying to right a capsized dinghy:
    http://www.youtube.com/watch?v=SZDXxcyqjjc
     
  4. stonedpirate
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    stonedpirate Senior Member

    You miss the point.

    A lot of people argue that sailiong around the world in a 30-40 foot boat is dangerous, foolhardy, too small to be visible, chance of getting hit hight etc etc.

    You can have all the safety precautions in the world, people still die every year on 30-40 footers. I am not saying its not dangerous.

    There is a percentage of people that will die driving their car to work.

    A percentage will die from flying in airplanes.

    And a large percentage will die from sitting on their fat asses at home watching tv and eating burgers after they get off the internet saying i am a dangerous fool.

    I have known 3 surfers that have died in the past 10 years. One shark attack, 2 drowned.

    Live and die how you want, i've made my choice.

    And i read all links, most of which i have already read.

    I read fathers day, alone against the atlantic and 500 days, all detail the true nature of being stuck in a small box at sea and none of them romanticize about it.
     
  5. stonedpirate
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    stonedpirate Senior Member

    Last edited by a moderator: Feb 9, 2012
  6. stonedpirate
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    stonedpirate Senior Member

    [​IMG]

    who says i'm not visible?

    can see me from miles away :p
     
  7. TrustedShips
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    TrustedShips Mr.

    Appreciate that you are able to animate the model with 3dMax.


    However, both the video and the image show something very hypothetical. Your model is just surging and slightly rolling. The software does not simulate other ship motions like pitching and yawing. As is clear from the earlier links from YouTube which I have posted, the actual situation is going to be far more complicated.

    The wave height which is visible in the video, if I compare with that 10' model, is below 1 m, ( Beufort scale 3).
    http://en.wikipedia.org/wiki/Beaufort_scale

    and the data for today shows the wave height in Atlantic to be quite higher than that (don't know about bad weather):
    http://www.stormsurfing.com/cgi/display.cgi?a=natla_height
    http://www.oceanweather.com/data/

    So better be prepared for that kind of situation.
     

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  8. stonedpirate
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    stonedpirate Senior Member

    Yeah, the motion of the boat is key framed from A to B with a 10 degree angle roll every 5 seconds.

    It is in no way a simulation, just a pretty picture.

    I am waiting for my new simulation to render that uses computational fluid dynamics to make the ocean interact with the boat give a realistic view of its movements.

    The good thing about max is i can simulate all weather conditions just by increasing wind speed, wave height, choppyness factor etc.

    Takes days for it to render in hi vis though which is a bummer.

    The above video is just a test for ocean and sky. Physics still to come :p
     
  9. TrustedShips
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    TrustedShips Mr.

    :cool:

    Appreciate it.... you are learning and enjoying the whole process....
     
  10. stonedpirate
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    stonedpirate Senior Member

    Good to see you read the whole thread :cool:
     
  11. Stumble
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    Stumble Senior Member

    Ok, to get back to the OP's question... I think your hull design is fine, for this type of trip it really doesn't matter so long as it is strong enough to take the forces involved since your speed is going to be limited to maybe 2kn anyway. Basically just enough speed to find the right currents to be in and stay there.

    I would recommend trying to reduce the weight in the keel though and try to hollow it out to act as additional storage for more food. As I see it this boat is so grossly unstable compared to what you will experience I can't imagine it staying upright, so use that as part of your design. The boat must be fully capable of spending time immersed, and inverted, so all the hatches need to be watertight, and bilge pumps on the ceiling might not be a bad idea.

    A rig that can be taken down and stored below during adverse weather would also be a requirement to keep it from being snapped off by rolling. This though has an advantage, in that you can fit a taller rig without needing to worry about stays since it will be lashed down in the event of bad weather anyway. Say a three piece rig with two sets of sails. One set for the tall set up, then remove a section and switch sails for two sections.

    You might also want to look into using a kite sail for propulsions. It will give you a lot more driving force than the small sails you could carry on a rig. Plus it will fly high enough to get out of surrface effects.

    I am still convinced you have no idea what you are in for, but if you insist... Just remember you are looking at 21,000 sea miles in this boat, so it must be made as strong as possible. Engineering this thing could be an expensive proposition to get the scantlings right, any mistake here could lead to a quick destruction in the souther ocean or north Atlantic.
     
  12. Submarine Tom

    Submarine Tom Previous Member

    Hey, Nutbar!

    Welcome back!

    -Tom
     
  13. old dog
    Joined: Dec 2011
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    old dog Junior Member

    Is my hull shape decent? Answer.

    At least your bum won't look big in it!
     
  14. gonzo
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    gonzo Senior Member

    This photo is of a mast tabernacle leak on a 25 footer. Turn your computer to make the drips vertical, and that will show what the average heeling angle was for about three days. I didn't advance at all in that time. The boat will pick up a bit of speed, climb a wave, almost stand on the transom and flop to one side or the other. The main problem with smaller boats, is that in the trough of the waves, there is little or no wind. The boat can't get enough speed to go forward or sometimes even steer with safety.
     

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  15. JosephT
    Joined: Jun 2009
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    JosephT Senior Member

    I'm inclined to agree with Gonzo. Such a short, stubby hull design is not much more than a glorified fishing bobber. Gaining any sort of direction in rough seas will be tricky, and staying on course will be tough.

    From what I've read ~25ft+ is the hull length range that seems to do best for open ocean.

    It would be REALLY interesting though to see how this boat does in big waves. I wonder if there is any marine analysis software that could simulate that hull in big waves.

    Put the word out and let's see if we can't get a video posted on youtube.
     
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