How strong is construction of this catamaran in storm?

Discussion in 'Boat Design' started by gp333, Feb 3, 2011.

  1. gp333
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    gp333 Junior Member

    Forget as this is solar boat etc. I talk about this type of construction. This is very close to trimaran, as middle hull very close to sea.. and probably in storm helps...

    [​IMG]
    [​IMG]


    I know this cat is fast on good weather... but what can do this 'thin rails' in high storm.. when waves 10-12 meters or more...

    Can more experienced persons say own meaning here...?
     
  2. Boston

    Boston Previous Member

    Solar panels are kinda heavy so I'd think its somewhat top heavy. My bet is they avoid any heavy weather like the plague. I wonder if water ballast in the amas would help it out some in rough weather

    cheers
    B
     
  3. gp333
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    gp333 Junior Member

    but on other side this yacht have 'on top' lot more than solar cells only

    [​IMG]

    and it is similar construction :)
     
  4. Boston

    Boston Previous Member

    OK then they both avoid serious weather like the plague
     
  5. gp333
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    gp333 Junior Member

    you wish say that catamarans and trimarans not good by bad weather?
     
  6. Boston

    Boston Previous Member

    Well as I move towards my retirement build I've put a lot of research into the issue and it seems that while a monohull can survive large waves better a cat can move more efficiently, so there's a trade off depending on conditions that must be considered. The cat tends to be built for smoother water and the mono's tend to be built for rougher water. So although each will find its optimum speed in the smoothest water possible the envelope for effective operation is narrower for the cat.
     
  7. daiquiri
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    daiquiri Engineering and Design

    With apparently so little buoyancy margin in those slim amas, filling them with water would definitely kill any residual righting moment, imho.
     
  8. PAR
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    PAR Yacht Designer/Builder

    I'm reminded of the uncharted atoll, that all the major multi hull designers seem to be living on, somewhere in the south Pacific. I can't really blame them, as the south Pacific is a nice place to hang out, though apparently communications with family, friends, clients and the rest of the world is forbidden on this atoll. Considering the surprising frequency, these guys seem to set sail and end up be drawn by the "sirens" of this atoll, never to be heard from again, maybe a word of warning . . .
     
  9. Ad Hoc
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    Ad Hoc Naval Architect

    The boat in question MS PlanetSolar is scheduled for a circumnavigation. Being solar powered, it is not going to be fast, taking an expected 140 days. Cruising speed is a mere 8.5knots.

    So at 8.5knots, in large seas she would slow down and just "wallow" or "bob" like a cork, ie heave and roll and pitch contouring the sea state. Since being out in the ocean these waves will be long period waves, not short crested. The motion wont be much fun!
     
  10. gp333
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    gp333 Junior Member

    I was say on start5: forget solar power!
    I am post 2nd image with lot more power in engines...

    Question is about construction...
     
  11. Ad Hoc
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    Ad Hoc Naval Architect

    Sure is. But to answer that question, it needs qualifying. What is the vessels duty and purpose. That defines the structure. Since being solar her speed is 8.5knots, not 40knots. If she were doing 40 knots, the end result would be very different!...therefore what the boat is "designed" to do is very relevant to the question you posed.

    Thus, she is solar powered, relatively light for her size travelling slow and trans-ocean.

    You cannot simply separate technical aspects of a boat, as each discipline affects others, and need to be understood and hence put into context.

    In other publicity photo's I have seen, the cross beam structure "looks meaty". Thus without knowing any more, she appears fit for purpose. But only time will tell.
     
  12. PAR
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    PAR Yacht Designer/Builder

    Considering her energy gathering and storage limitations and consequently her propulsion restrictions as a result, saving weight must have been a huge mission in the process of engineering her structure. I can only assume, particularly in light of her project budget, she's sufficiently stout for the tasks asked of her, though I'll bet her design team sweats bullets with each passing low pressure area.

    I think you need to refine you questions a bit, as their broad and seemingly innocuous nature suggests you are looking for answers where none really exist. Is there something specific you had in mind?
     
  13. gp333
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    gp333 Junior Member

    :) simple refining question:

    This catamaran construction, with not strong engines (but not so small like in solar example) like 2 x 80HP as example in bad weather condition (by any sea) and no exist additional decks on top:
    [​IMG]

    YOU HAVE FULLY MY IDEA IMAGE NOW ABOVE

    monohull vs. this multihull concept like that...
     
  14. Boston

    Boston Previous Member

    80 hp wouldn't drive the gen set. I think your looking at more like 800 hp. The question your driving at would require a pretty detailed analysis of the actual design specs. Which is unique to each of the two boats. You'd have to go to the original designers of each.

    in the end these guys run from bad weather as best they can and after that as Par pointed out they just mostly sit there and bob around in a rough sea waiting it out. The non solar boat most likely has the power to make sufficient headway but the solar boat seems like it would be in a wait it out mode

    cheers
    B
     

  15. gp333
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    gp333 Junior Member

    80 hp wouldn't drive the gen set. I think your looking at more like 800 hp.
    RE: I say 2 x 80HP... yacht is as 30 meters long and no exist above decks!
    plus as you see main "power" is from 2 sails!


    The question your driving at would require a pretty detailed analysis of the actual design specs. Which is unique to each of the two boats. You'd have to go to the original designers of each.
    RE: sure I know :) these are some general thinking only


    in the end these guys run from bad weather as best they can and after that as Par pointed out they just mostly sit there and bob around in a rough sea waiting it out. The non solar boat most likely has the power to make sufficient headway but the solar boat seems like it would be in a wait it out mode
    RE: ugh, I say from start forget solar power.. i talk about cat construction!
    you ask here exactly what i mean and I just post above by full 'vision' image. bi-plan cat
     
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