Advanced Commercial Aluminum Catamaran

Discussion in 'Multihulls' started by anthonydimare, Aug 7, 2015.

  1. anthonydimare
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    anthonydimare Junior Member

    I'm looking to learn more about how Aluminum is being used in commercial vehicle design. It seems clear that aluminum in the Aerospace and Automotive industries is much more prevalent. Why is that? What's holding the marine industry from doing the same. Curious to find other who'd like to discuss aluminum structure design and where it can be used to decrease overall weight, and make large marine craft more efficient.

    Let the onslaught begin!
     
  2. gonzo
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    gonzo Senior Member

    In aerospace weight is of crucial importance. In automotive, there is some aluminum, but the bulk is steel. There is nothing holding the marine industry back. Aluminum is used in many vessels, when the material is appropriate for the use.
     
  3. anthonydimare
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    anthonydimare Junior Member

    Thanks gonzo, any examples of industry technique crossover? I'm interested in creating ultra-efficient electric marine vehicles. Weight is crucial to the success of the project which leads me to believe that aluminum would be the ideal material for the majority structure.

    Other questions/ comments: Any good documentation on Aluminum structural design/fastening methods? What's the most robot assist-able joining method?
     
  4. DCockey
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    DCockey Senior Member

    Why aluminum rather than advanced composites if weight is critical?

    What type of vessel and structure?
     
  5. anthonydimare
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    anthonydimare Junior Member

    Cost, durability, engineering design "know how", all point to aluminum being the better choice over composites for the majority of the structure and hull. Don't have the resources or money that Boeing has to dump into a massive R+D disaster. Not to say it wouldn't work, just not the right material for the application.
     
  6. waynemarlow
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    waynemarlow Senior Member

    Aluminium is already widely used in marine applications from small fishing boats to huge fast cat ferries, what is not being used is composite Ali panels such as the high tech car manufacturers where it's often used in chassis and side panels for crash protection.

    But the cost setup of this type of composite panel is huge and requires large volumes. In steps our favourite, Carbon and some of the more exotic fibres appearing on the market at prices Ali can't compete with.

    The other question is why make life difficult for yourself when modern composite processes are proven and are reliable in the marine environment.
     
  7. JSL
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    JSL Senior Member

    Where have you been? Aluminum has been used for many years (45+years in our region) in commercial vessels that benefit from lighter weight.
     
  8. DCockey
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    DCockey Senior Member

    Can you provide any information about your application beyond it being "ultra-efficient electric marine vehicles" and apparently catamarans based on the thread title? how will efficiency be defined? How large will the vessels be? Size factors for different criteria come into play and aluminum may not be as weight efficient for small vessels as it is for larger vessels. How fast? Protected waters or offshore? What production volume is envisioned?

    Perhaps you should spend some time also investigating the current state of boatbuilding with advanced composites. The "optimum" solution for your design may use several materials and technologies.
     
  9. DCockey
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    DCockey Senior Member

    Continuous welding appears to be used for fastening in most aluminum boats. Robotic welding usually needs high volume and high accuracy in other aspects of fabrication to be cost effective.
     
  10. Ad Hoc
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    Ad Hoc Naval Architect

    antonydimare

    It seems you have been ill informed and corrected by several posters above. Aluminium has been used in the marine industry for decades. The US is slowly catching up with the EU and other locations in terms of using aluminium for the marine industry, but make no mistake, it is a fully mature industry.

    You are also mistaken in equating lightweight with efficiency. Efficiency of what?...without context is it a meaningless statement.

    AS for structure, the structure of a vessel equates to around 20-25% of the vessels overall displacement. Thus depending upon what is your design and its SOR, you really need to take a proper holistic approach, just as any naval architect must, to ascertain where/how to save weight and not be myopic and think the material weight alone shall achieve your objective - whatever "it" is.
     
  11. Jetboy
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    Jetboy Senior Member

    IMO - aluminum in marine use has passed its "sell by" date. Carbon FRP composite structures are stronger, lighter, and more resistant to corrosion. Airplanes are leaving aluminum as well to move to carbon composite.

    That's not to say you can't build in aluminum. Just that it doesn't make sense when you can build a better boat for the same or less $ in carbon. From bicycles to automobiles to airplanes, carbon is replacing aluminum and steel.

    My boat has lots of aluminum parts - but only because I can't afford carbon yet.
     
  12. redreuben
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    redreuben redreuben

  13. Ad Hoc
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    Ad Hoc Naval Architect

    Hmm..this statement:

    is at variance with this:

    If it is same or cheaper to build in carbon, than ally..why can't you afford it?
     
  14. upchurchmr
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    upchurchmr Senior Member

    Ad Hoc has a great question.
    In Aerospace I can make aluminum at 1/4 (typical panels) to 1/9 of the cost of carbon composite - these are actual recent examples.

    Boat building is not the same as aerospace - but I don't believe the statement that you can make composite cheaper than aluminum.
    Perhaps the builders capabilities is more important in that statement.
     

  15. Mr Efficiency
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    Mr Efficiency Senior Member

    Jetboy's assessment of relative costs of aluminium Vs carbon fibre seems to be well astray. And I have no idea why it is Aluminum in North America, but Alumin(i)um in lots of other places !
     
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