Aluminium Catamaran in the Kimberley

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    • #2608


      After your thoughts on pros and cons of venturing into the Kimberley on an aluminium catamaran. Most cats I’ve looked at are fibreglass.

    • #2609

      Hi Snow. Power or sailing cat?

      There are many pros and cons when it comes to choosing between an Aluminium or Fiberglass (GRP) boat. In the end, it’s largely a matter of personal choice and cost. Custom built alloy boats are usually cheaper to build than custom built GRP. Both materials do the job well, provided the boat is properly designed, built and maintained.

      There is however, a big difference between power cats and sailing cats. Sailing cats are very weight sensitive, and most modern sailing cats designed for long range cruising are built from light weight composite GRP materials, which are both strong and light weight. You will struggle to find an alloy sailing cat that will come anywhere near a composite GRP cat for performance, until you get into the bigger, 20 meter plus designs.

      The weight of fuel and large engines dictate that most cruising power cats are longer than 15 meters, where the weight factor starts to become less critical. A well designed and built power cat in either material is suitable for long range cruising.

      If you are looking at buying a cruising boat, “well designed and well built” are the two first things you should consider.

      For what it’s worth, my personal choice is GRP composite construction.

      Cheers, Ross.

      • This reply was modified 2 years, 1 month ago by Ross.
    • #2611

      Thanks Ross,

      Boat I am looking at is a sailing cat with two 54hp Yanmars

      • #2651

        Weight of an aluminium sailing catamaran is often subject to erroneous opinions expressed by designers and manufacturers of GRP vessels. A bit of a myth perpetrated by mass production houses.

        Our Mumby Cybercat 48 was dry weight 8,500kg when hauled with a travel lift with weighing capabilities in 2009. At the same time the travel lift hauled a new 48′ GRP cat that weighed 18,500 kg, dry (no water, no fuel).

        Alloy is 4mm below waterline and 3mm above waterline. Length 14.8m, width 7.6m and draft 1m.

        Strength is a whole other issue. Lifting with a Roodberg trailer, such as at Spot On Marine in Darwin, demonstrates no distortion when suspended on the trailer arms. However, GRP vessels may distort and in some cases damage.

        We met two cat families that had their hulls crack when lifting with a similar trailer.


        Jeff Boyd.

        Jeff Boyd and Anne-Marie Fisher</div>
        SY Kaitoro
        Mumby Cybercat48

        • This reply was modified 1 year, 11 months ago by Kaitoro.
    • #2654

      Gday snow                                                                                                                Id reckon the best way to make any comparisons on which material (core) is the best choice would be to count the amount of boats above the 8 to 10 metre range that are made of aluminium in any marina any where. There are many reasons why fibreglass is the preferred choice, pick up a sheet of 20 ml thick duflex with either a balsa or foam core then go pick up the same size 2400 x1200 sheet of 3 mm aluminium and see who wins,  fibreglass/ composite boat construction has come along way in the last 20 plus years, resin infusion , vacuum bagging, duflex kits etc all aimed primarily at weight reduction. Positive bouancy, insulation properties, (much cooler in tropical climate plus less noisey, no corrosion (electrolysis), more paint choices both above and below the waterline, easier to repair if you punch a whole in it, not  every one can tig weld specially not parked on a bit of reef in the middle of the Kimberley, most people can glue to bits of wood together though             Respectfully.    Steve

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