Law abiding Kiwis.

Discussion in 'Multihulls' started by Gary Baigent, Mar 31, 2020.

  1. Bob Oram
    Joined: Jun 2009
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    Location: oz

    Bob Oram Junior Member

    Old multi, I was on Malcolms boat about 5 miles inshore of Yumi when she went over. We later realised we had seen the flare but thought it was a shooting star. oops
    Gary, Top Gun the 50' pod cat built in Cairns for Wayne ? had the same rudder ventilating issues at around 20kts, as did 'Rontidgu' (excuse the spelling) when I stood it on it's nose at about 23kts in Gladstone Yepoon race.
    Russel, Very much like the clear finished stabilised mono photo you posted on the thread re the kiwi fellow wanting to build the alloy one.
    I think he needs 50' though.
     
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  2. Gary Baigent
    Joined: Jul 2005
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    Location: auckland nz

    Gary Baigent Senior Member

    New 4.5mm thick ply box beam for Groucho; this photograph taken 6-7 weeks ago but since then have finished making it aerodynamic by adding curved near semi-circular leading and less curved trailing edge areas out of thin 2mm ply (rare stuff to obtain in NZ). After fairing and painting, going to shove the platform off the bank at next 3.6 metre high tide.
     

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  3. Russell Brown
    Joined: Jul 2012
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    Location: washington state

    Russell Brown Senior Member

    Hi Bob, How's the Mary river? I finally figured out what you were talking about with the stabilized mono. Just did a re-design of that boat and one is being built on the East coast. I'm going to build one to be able to write a building manual.
     
  4. Bob Oram
    Joined: Jun 2009
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    Location: oz

    Bob Oram Junior Member

    Hello Russell, nice to talk again.
    Very dry in QLD at the moment. The Mary river has stopped flowing until we get some rain. Purely tidal now.
    Interested to see the response to the update of the little power boat. What are calling the design and that particular configeration.
    Regards
    Bob
     
  5. Gary Baigent
    Joined: Jul 2005
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    Location: auckland nz

    Gary Baigent Senior Member

    Will push Groucho off the bank in next month's 3.6 metre high tide.
     

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  6. Bob Oram
    Joined: Jun 2009
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    Location: oz

    Bob Oram Junior Member

    Hello Russell,
    Now that I've retired (and when I sell Slim), I'm looking to build a new power boat for myself for remote area cruising in the Territory/Kimberely etc (the hot version of your Alaska, swapping bears for crocs ). Going around in circles a bit re type/design. From 10mt pod power cat (smaller version of the 12mt one I did in 2009 that I still kick myself for selling), to a 36' LDL retro style mono.
    But I have a suspicion the simplest and probably most effecient boat would be a power proa, say around 45'.
    Any thoughts you would be happy to share.
    Regards Bob
     
  7. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    I would love to see the 10mt pod power cat Bob. I am a fan of yours. Is that the one I've seen on youtube? What a sweet boat. I am building a demountable 10m powercat by Richard Woods. Hardly want to break into this thread, but couldn't resist saying hello.
     
  8. Russell Brown
    Joined: Jul 2012
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    Location: washington state

    Russell Brown Senior Member

    Hello Bob,
    The single outrigger seems like the boat of the future if you want low horsepower and good seakeeping qualities. Seems like if the outrigger hull is long and narrow, you hardly know it's there, except that it keeps you upright.
    You are the perfect guy to design a good one...
    Recently did a re-design of the 24 footer with Paul Bieker for a client on Cape Cod. It's a bit longer but got built with surprisingly few hours and is just about ready to trial.
     
  9. Bob Oram
    Joined: Jun 2009
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    Location: oz

    Bob Oram Junior Member

    Hello Fallguy,
    No, the video shows the 12mt x 5.5mt version.
    With a pair of 60hp HT Yamahas,[spinning 13" x 13.3/8" props] the boat did 21 kts WOT [5200rpm]. [We also use Tohasu, Honda and Suzuki outboards with equal success].
    The boat cruised at 14 kts at 1lpm at approx 3500kgs. I tend to over pitch props a little as I want them to have max grunt down at economical revs. Interestingly, at 8kts on 1 motor the lpm was nearly the same.
    The pod was 9mts x 2.5mts.
    Because it was 'airborne' ie didn't share any airspace with the hulls it was very, very quiet. At an idle the motors couldn't be heard, you had to check the tachos to see if they were running. At cruising speeds [especially with the back door closed] there was a distant humm.
    I think Russell's single outrigger [now called RSO concept Russell :) ] concept has a lot of cred and is probably going to be the way to go.
    It should be remembered that the best way of building a quick, easy and inexpensive boat of any sort , is to 'build less boat'.
    As mentioned on another thread. If you take the accom etc off the bridgedeck floor and put it down into the hull you reduce the height therefore windage, by probably a metre [3.2808 ft]. Obviously you also reduce the build weight, time and cost considerably as well.
    These are all important considerations for anybody but especially older guys doing their simple retirement boat, ie ruthless about getting rid of anything that isn't absolutely essential.
    Which is why I/we use 4 stroke outboards up to about 8 tons disp [in boats up to 15mts].
    One of the many reasons is; Our spare parts locker consists of 2 spark plugs, 1 impellor, 1 fuel filter, 1 oil filter and 2 lts of oil. About 2.5 kgs of weight and about $100 in money laying in a locker. This is for a 6month cruise in remote areas. Ask the diesel guys how much money and weight they have tied up in spare parts.
    I will admit though [having spent about 10 years off and on in trawlers, barges, ships etc.] there is an organic comfort in the quiet throb of a diesel [perhaps learnt listening to Mums heart when young very very young].
    The hulls will be single chine and very simple in shape, which makes them perfect for flat panel construction and materials.
    Reasonable quality plywood is a logical, light, inexpensive, low tech method of building. I have been glassing BOTH SIDES of plywood for NEARLY 40 years [need I say it, using epoxy of course] and have had absolutely no issues.
    Logic would dictate a foam cored cabin roof, mainly for it's insulation properties and slight reduction in CoG, which in turn would very slightly reduce roll and pitch moments.
    Hope this is of interest Fallguy.
    Regards
    Bob
     
  10. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Any discussion about powercats is interesting.

    Here is the one I am building

    13DBA3A3-CFAF-4392-A490-6A175472EF7C.jpeg
     
  11. Bob Oram
    Joined: Jun 2009
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    Likes: 7, Points: 3, Legacy Rep: 111
    Location: oz

    Bob Oram Junior Member

    Hello fallguy,
    Did I read correctly that they are 90hp motors on the boat?
    Wow, should skoot with that much power.
    Bob
     

  12. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    Yes, we put 90s on. A bit worried about the weight of them and the jack plates at 122# each per side, but the spec was F70 which is super light to start. The only reason I went away from RW spec was to get a little more alternator output (double for autopilot), but of course, that morphed to being able to put extra longs on and get the powerheads up 5" with a jackplate and some adjustment to the engines versus the 20" transom..
     
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