Weekender/Picnic Vessel, Power and/or Sailing Catamaran

Discussion in 'Boat Design' started by brian eiland, Jul 16, 2010.

  1. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Single Engine vs Twins

    Now here is a subject that I'm sure will draw lots of conflicting opinions. In my opinion there are basically 2 arguments for twins verses a single,....maneuverability and safety-in-pairs. I'm going to start out with the question of maneuverability first, and leave the safety aspect for another time.

    Yes, twin engine/prop boats are generally more maneuverable than single engine/prop ones.
    But let me relay a personal experience I had with a single engined outboard on a 37 foot catamaran I imported to the USA.
    upload_2020-4-11_12-36-44.png

    upload_2020-4-11_12-37-10.png


    I utilized a single Yamaha 9.9 Hi-thrust outboard engine mounted like above. I had rope lines run from the tiller arms to the single outboard engine that would be engaged (cleated) only during low speed maneuvering under power.

    That steerable engine combined with the rudder action provided extremely good control. I could almost 'parallel park' that vessel !!

    That experience leaves me asking, ….'why dual engines for maneuverability' ?
     
  2. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Some more discussions of outboard power on larger cruising catamarans,..
    outboard power on larger cruising cats https://www.boatdesign.net/threads/outboard-power-on-larger-cruising-cats.56260/page-2

    And a particular posting I made on that subject,..
    Central pod/nacelle idea

    If I were looking to use my auxiliary engine in a strictly aux manner, rather than in a motor/sailing demand, I would seriously consider a single engine installation. This engine would be conveniently mounted in a boxed enclosure on the cockpit deck and would belt drive a steerable out-drive leg that would be incorporated into the rear portion of the central nacelle structure. (note: I am suggesting a central nacelle structure for several other reasons also)

    Maybe this rear nacelle might appear as on "Earthling's pod" (attached photo). This saves the cost and weight of the second engine, trans, shafting, prop, etc, and opens up the rears of the hulls for a nice master berth, or whatever.
    [​IMG]

    I say steerable as a result of my personal experiences with an installation I had on a Louisiane 37 cat. I had lines run from the tiller arms to the single outboard engine that would be engaged only during low speed maneuvering under power. that steerable engine combined with the rudder action provided extremely good control. I could almost 'parallel park' that vessel.
     
  3. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    If it was not an outboard being utilized for power, then the box for an engine of some sort could be located somewhere on the aft deck and powering a retractable leg that reaches down thru that central nacelle, preferable more forward than at the stern.

    1) That more forward prop position would keep it in contact with the water better than a pitching position at the stern.
    2) That 'box cover' on the deck might make it much more serviceable.
    3) A variety of engines might be candidates.
    4) For the strictly powerboat version/model, the prop leg might not need to be retractable.
    5) The central nacelle might only need to be a relatively thin structure as it only needs to hide/support the drive leg when it powering in a straight line, not when its turned for slow speed maneuvering.
     
  4. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

  5. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Steyr engine powerhead?

    I have always been impressed with this company's compact lt-weight engines. They have a relatively new common rail diesel 4 cyl engine,..
    A masterpiece of engine design: STEYR MOTORS SEC 4-cylinder - Steyr Motors http://www.steyr-motors.com/news/news-single/a-masterpiece-of-engine-design-steyr-motors-sec-4-cylinder/559c19bd87fe3393ae1798b54c98e341/

    Its light weight
    It puts out 80-170 HP
    It is commom-rail injection, which might allow it to operate in a variety of 'attitudes'

    I'm wondering if it can be hooked up to out-drive leg like that on the 'big red boat', and that outdrive leg's prop end be a duo-prop counter-rotating one off an existing outboard?

    Might be a heck of a set-up, perhaps not the cheapest, but maybe less than twin engines, and their subsequent mounting??

    I've made an inquiry to the Steyr company to see if they have run into any unusual deployments of their small engines.

    PS: I'm spending time up front on this powering subject as it might have a significant influence on the subsequent design of the vessel itself.
     
  6. brian eiland
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    brian eiland Senior Member

    bajansailor likes this.
  7. brian eiland
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    brian eiland Senior Member

    .....from a posting by Manie back in 2009,...with photos attached
    Discussion: Pocket Cruising Power Catamaran Design for Recession Times... https://www.boatdesign.net/threads/discussion-pocket-cruising-power-catamaran-design-for-recession-times.25620/#post-248257

     
  8. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Surfari 50 sailing/fishing vessel
    One of the reasons I got started out on the search for an alternative weekender / sportfishing vessel was when I saw the vessel they claimed they were designing/building for Jimmy Buffett. The Surfari started out as a 44' design, and evolved into a 50' version. There is considerable documentation of her here, and a number of other sites/discussions.
    Jimmy Buffet just bought one of ugliest sailboats I have ever seen... http://forums.sailinganarchy.com/index.php?/topic/168372-jimmy-buffet-just-bought-one-of-ugliest-sailboats-i-have-ever-seen/&
    I just felt it was the wrong vessel for his shallow water preferences/fishing styles. Its a nice looking concept idea, but just totally wrong for him,...and many others.

    Seawind 1260
    So I am proposing to come up with something better. BUT if I was being ask to choose from an existing design, here is one I would very much suggest. Modify her a little bit with some fishing attributes, and you would have a vessel for considerable less money, and even better attributes.

    Check out this interesting video here,


    Some good photos here,
    2021 Seawind 1260 Owners Version Catamaran for sale - YachtWorld https://www.yachtworld.com/boats/2021/seawind-1260-owners-version-2767800/

    One of these vessels could be had for approx 400K, compared with 2.8 M he paid for that Surfari vessel.
     
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  9. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Just happened across this (much) older posting on another forum,
    Cat Fishing - General Catamaran Discussion | YachtForums: We Know Big Boats! https://www.yachtforums.com/threads/cat-fishing.9207/#post60026

    Wonder if he ever found a vessel,...even a smaller weekender one to live out his dream?? Sound like he had a good area picked out.
     
  10. brian eiland
    Joined: Jun 2002
    Posts: 4,948
    Likes: 179, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

  11. brian eiland
    Joined: Jun 2002
    Posts: 4,948
    Likes: 179, Points: 73, Legacy Rep: 1903
    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

  12. brian eiland
    Joined: Jun 2002
    Posts: 4,948
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

    Doesn't appear to be that much interest in this subject at the moment, so perhaps I will just let it rest until we get over the pandemic and into better summer weather and subjects.
     
  13. brian eiland
    Joined: Jun 2002
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    Location: St Augustine Fl, Thailand

    brian eiland Senior Member

  14. fallguy
    Joined: Dec 2016
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    fallguy Senior Member

    I considered them for a moment for the Skoota I am building. At a cost of more than $25,000 each, I could not see it for my boat. Somehow, my recall was $60,000 for two. I got two 90hp engines for $18,000. And not sure what the alternators are in the dtorque with all that powerhead in there, but I am getting 32 amps.
     

  15. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Alternator in dtorque is 25 amp; not bad at all.

    Just price killed me on them.
     
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