which cat for me?

Discussion in 'Multihulls' started by Grizz, Aug 31, 2008.

  1. Grizz
    Joined: Aug 2008
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    Grizz Junior Member

    so if aluminum can't make a good catamaran, are there any successful trimarans built of aluminum?

    curiously,

    Grizz
     
  2. jaydh
    Joined: Aug 2007
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    jaydh Junior Member

    tin cats

    Hey guys,

    Grizz...got your pm, apologies for the delay. Look at www.far-away.net and check out Chameleon and Mozart. Both alloy cats same shell I believe with different layouts. Once again, larger then what it seems you were thinking of, but hell, fun for a looksey.

    I see a few digs at aluminum for cats in this thread. I'm about as far away from an expert on this, but a wise man once told me to beware the experts! Thought I'd throw this in the mix to play cheerleader for aluminum.

    My lovely wife and I are building a 14m alloy sailing cat and we too were wary up front. Heard all the horror stories....was it Alco in the States that had a bad batch that screwed up some larger power cats in the NW area? Rampant corrosion, too heavy, PHD needed to weld/design aluminum, etc, etc.

    Alum is fairly popular in Australia. They love the stuff here and a few guys have been turning out alloy sailing cats for years. 40some foot range is the average size I've come across. 4mm hulls and 3 or 4mm deck for the sheets. We routinely weld 3mm and that's less then 1/8" yeah? 2mm easy also....welding straight forward...keeping it from distorting...now that separates the men from the boys! Years of cruising noticed the experienced cruising Euros preferred alum monos....hey!...if the French like it can't be that bad. ;-)

    We have four mates that have the same cat as we're doing and know of 10 or so more out there. They all go fast, are pushed hard and have even hit steel things at 10 knots. No dramas. Corrosion not the boogey-man as rumored (though one can't be stupid and ignore it). It's easy as hell to work with and the end result only limited by your own patience and skill. Quick to build....no curing times/windows, etc....and ya don't even have to paint above the waterline if one chooses.

    Anyone out there thinking of building a cat in the 40-50 foot range do take some time to check out alloy. It'll either be for you or not, but at least worth the effort to research. Alloy is fun to work with and decent results obtainable by amateurs like us. Below a few pics - the one without the cabin is ours...the other two a mate built in the same shed last launched a year ago.

    best - Jason
     
  3. jaydh
    Joined: Aug 2007
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    jaydh Junior Member

    crap...pics didn't upload...will try again later in case anyone interested...

    - J
     
  4. jaydh
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    jaydh Junior Member

    pics

    trying again...
     

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  5. Grizz
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    Grizz Junior Member

    Wow Jason that looks good. 3mm is right at 1/8" and I've welded that no problem. 2mm seems thin, but engineering and good welding technique takes care of that. What type of internal framing? What size and spacing? Are you MIG or TIG welding the 2mm sheets? Are you using ply for interiors? Are you using foam for insulation?

    Please post more pictures if you feel inclined, I appreciate the ones you've posted.

    I love the tikis but they seem like throw-aways. Your boat looks very comfortable and long lived...

    Regards,
    Grizz
     
  6. masalai
    Joined: Oct 2007
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    Location: cruising, Australia

    masalai masalai

    Arrr Jim, little terriers are better rat/mouse catchers ***** cats need to be "altered" as cats are boats and ***** is part of something else again....

    Now a little bit more serious, 40ft is a nice comfortable size range for a cruising cat - I like a beamy 20 to 24 ft on fairly slim hulls - look at Bob Oram Designs 44C (my choice is the 39C with forward cockpit) http://www.boboramdesign.com.au/39-c/ or the Fusion 40 which is available as a kit or built in USA http://www.fusioncats.com.au/

    I suggest, buy for resale, as big as you can afford and most importantly TRAVEL LIGHT for weight kills any advantage of a cat - - If you like to add this, that and many other things too then DO NOT GET A CAT....
     
  7. jaydh
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    jaydh Junior Member

    Hey Grizz,

    The 2mm is not in the boat...we just welded some scrap to see if we could do it. Have some 2mm diamond plate for fun cosmetic stuff....that was just a welding comment.

    The full deck has stringers running fore and aft roughly 300mm apart with gussets installed between everything at 300mm again. The side sheets and bottom plates follow the same 300mm spaced stringers more or less without the gussets. Here you have 13 bulkheads per hull (two of which are watertight #4 & #11). without checking the exact measurements of each you can pretty much say they are equally spread out fore and aft more or less. this is of course a very simplified explanation. I'll have to put some shots up before the bottom plates went on and the deck inside.

    We are using MIG. Got a sweet Fronius 2700 and love it. 5183 wire. 1.2mm. Plain old argon. A few sconds and you're welding steel then TIG. Easy set-up, whole thing WITH a 6kg roll in it weighs just 20-30kg or so. Simply love the pretty red-orange thing!

    insulation we're going to try Armacell/Armaflex as opposed to the 2-part spray in others have been using. No ply...all plastic for the finish...probably rigid pvc foam or something like Multiboard. Deck will be a product called Aquadeck from Comcork Australia...made from recycled tires and cork.

    The other guys have been getting their fitouts done in the Philippines and it does look great....full on glass and custom/local wood floors. Will post a pic of that too...we just don't have the time to do that. I heard the full fitout in the PI is 15,000 and takes 7-9 months.

    Thanks for your interest....I too just like to look around and see what others are up to. Pics up sooner or later....

    best - J
     
  8. northerncat
    Joined: Jan 2007
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    northerncat Senior Member

    how much did the fronius set you back?
    sean
     
  9. jaydh
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    jaydh Junior Member

    fronius

    Hey Sean,

    Long time no hello...last time was when we were in Las Vegas, I think??

    The welder was between 10 & 10.5k. Got it new from Queensland welding supply on Lytton Rd Brisbane outer suburb. Was much more then we wanted to spend, but haven't regretted it for a moment. QWS has been great to deal with, btw.

    Looked at several used MIG and they were trash and still half + of the new Fronius. No decent deals were available and we were pressed for time to get rolling. Still happy we bit the bullet on this machine. Not one drama with the fronius push/pull gun and we use it nearly every day since February. One LED light on the interface wants to go out now and then, but it doesn't affect anything else. Will just fix that when it's convenient. Otherwise, not one hiccup.


    best,
    J
     
  10. Grizz
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    Grizz Junior Member

    I have a 300w thermalarc inverter running a miller 1# spool gun. I ran it 3 phase off of my boat generator. Works for me. I'd like to try TIG some day... never have but it looks like fun, and I do fairly well acetylene welding steel so I think I can do it. Unless my motor skills have deteriorated too much!
     
  11. northerncat
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    northerncat Senior Member

    yes great to see the progress of your boat, mines now floating but it's just a motorcat at present, i am thinking fairly seriously of building an aluminium boat next so i may know where to get a cheap fronius in 6 mths judging by your progress :cool:
    have you managed to stay in the figures that you were talking earlier?
    sean
     
  12. jaydh
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    jaydh Junior Member

    sean...sent you an email. sean, grizz here's two finished, same model.....
    J
     

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  13. TomT
    Joined: Oct 2008
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    TomT New Member

    Haven't been there or done that, but I have cruised the net for years. Two places to see alloy cats-www.bodenboatplans.com heavy displacement but designed in steel or alloy. Also an older site home designed home built by a self taught welder Tony Bigras-www.ideaintegrator.com/boats/ Osram VI Historical site no longer active but shows what can be done in alloy lots of
    info but states plans are not made available. The idea of two alloy huls joind by lashings ala Wharram seem to be a great solution to the cycling problems that can bee associated with alloy hulls.
     
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