Attention Australian builders

Discussion in 'Multihulls' started by rob denney, Apr 18, 2007.

  1. rob denney
    Joined: Feb 2005
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    Location: Australia

    rob denney Senior Member


    Most builders have read about the Kelsall KSS technique for rapidly building boats and wondered if it is really possible to build hulls this quickly. If they are, it makes a mockery of spending weeks gluing, glassing, bogging and sanding strips of wood or foam in the traditional strip plank method, or any of the heat it, bend it and screw it foam techniques.

    Harryproa have decided that this development is too good to miss and have paid Derek to adjust the design of the hulls of the 15m/50' proa we are building for me to race in next year's Solo Transpac. As part of the deal, Derek is putting on a 4 day workshop at our factory in Urunga (midway between Brisbane and Sydney, 20 minutes south of Coff's Harbour) to demonstrate how infusion and KSS work. He reckons that at the end of it, we will have the hull ready to top coat paint, and a 15m vacuum table. It would take more than 4 days to fill and fair the hull of a 15m strip planked boat, so this will be a very impressive achievement.

    The workshop is from 17-20th May (just before Sanctuary Cove show). Anybody who wants to attend is welcome, at a cost of $500 for the 4 days. This includes lunch, morning and afternoon tea, the chance to participate in the build and to pick Derek's brain on the technique. Mostly though it gives you a way to save a huge amount of time building your own boat. Local low cost accommodation is being organised.

    Anyone interested in attending, please email me at or phone 08 92843483.


    Rob Denney
  2. DennisRB
    Joined: Sep 2004
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    DennisRB Senior Member

    This is the first I have heard of the method. Does the design of the hull shape need to be compromised to use this technique?
  3. lazeyjack

    lazeyjack Guest

    I would be extremly suspicious, Aussie boatbuilders are , well, not so great ,they were they silly buggers that reckoned you could form a metal hull with explosives Soon i,m going to post a pic gallery of the worlds worst boats, and guess what, they are all from here!!\
    there are seminar scams here every day of the week
  4. DennisRB
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    DennisRB Senior Member

    WTF? Explosions to build metal hulls? I need some pics.
  5. lazeyjack

    lazeyjack Guest

    i kid ya not, they dig a hole the ground line it wiv allunimium, of ****!! it was so much Bull crap, but i swear it is true
  6. DennisRB
    Joined: Sep 2004
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    Location: Brisbane

    DennisRB Senior Member

    Man you need to find some links, that is amazingly insane.
  7. PI Design
    Joined: Oct 2006
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    PI Design Senior Member

    Hey LazeyJack,

    Rob D is definitely not a scammer, and neither is Derek Kelsall. I used to live near to Derek and have seen boats being constructed using the KSS method. I'm no expert at all, but it certainly seems to be a quick and simple method of construction that gives high quality results. $500AUS for a 4 day course seems good value to me for anyone considering building a multihull.

    Now, using explosives to make a hull, that sounds like fun...
  8. Crag Cay
    Joined: May 2006
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    Crag Cay Senior Member

    Derek Kelsall can hardly be dismissed as an 'Aussie Boatbuilder' and even if your general observations about them are true, extending this to Derek is at best ignorant, and at worse grossly insulting. He is the guy who pioneered glass / foam sandwich and designed, built (and raced) a lot of the early successful big racing multihulls and monohulls including OSTAR and RBI winners. He is a designer and engineer of the highest calibre.

    Like many multihull designers he is constantly searching for ways to reduce the cost of one-off building, principally by reducing tooling costs and labour time. After a lifetime of practical hands on experience with every method under the sun, he is convinced that his KSS technique is a significant step in the efficient building one off glass / foam cored boats.

    The debate about fibre orientation and shape compromise was played out more than 10 years ago around the world at design conferences and in the press, fuelled by some misrepresentation disseminated from a rival multihull designer in Seattle. The conclusion after all the mud slinging ended, was that none of it had stuck to either Derek or his methods and his reputation as one of the great innovators in the multihull world remained intact.

    This is reinforced by the sheer number of his designs that have been built around the world and continue to give excellent service, some after more than 40 years of hard sailing.

    We don't see as much of Derek here since he moved out to New Zealand, but I would encourage anyone with an interest in one-off glass / foam cored construction of any type to go and see and learn from someone who was there at the beginning, has done so much at the very highest level and even in his 'third age' is still blazing a trail while other wallow in his wake. If there was a Yacht Designer / Builders Hall of Fame, Derek would be one of the early inductees.
  9. lazeyjack

    lazeyjack Guest

    ok --------------- fine
    but the explosives thing, really they were serious!!:))
  10. lazeyjack

    lazeyjack Guest

    and, I should keep out of debates on that sticky ****, what i know abt glue , can be written on back of a postage stamp
  11. catsketcher
    Joined: Mar 2006
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    catsketcher Senior Member

    Gelignite does float

    The explosive boat was a 35 footer (or pretty close) that sailed in Middle Harbour in the late 80's. Nice boat. They roughly welded the aluminium in simple curves - no rolling of plates, and then put it in a concrete mould. The hull was then filled with water and a charge let off. The shockwaves pushed the plates onto the mould - complex curves with no rolling. Good idea from my perspective.

    As an Aussie builder I must take issue with the sentiments that we make lemons. Aussie multihulls can be darn fine boats.

    On Dereks method - I think it is very well suited to Rob's type of boat. Producing long hulls quickly is just what Harry proas leeward hull needs. I am more sceptical of KSS being useful for a wider audience. Fairing a hull side just isn't that hard! It is the corners and insides that hurt.

    I know some people will scoff at that but on a normal boat I would prefer to have computer cut interiors to reduce times spent building and this means a hull built to close tolerances on a normal jig. Hulls don't take much time to build, it is the interior of the modern cat that takes an awful amount of time. Any large boat will take many thousands of hours to build. Saving two hundred hours or so is not worth it if the design is not what you want. For me the constraints of not being able to develop compound curves and flared hulls means the KSS is not for my particular style of boat. For long thin hulls with few interior parts it could be a lifesaver.

    For my part I would love to go to the clinic just to ask Derek about the boats he has built and designed - Trifle, Toria, Great Britain 1 2 and the rest, winning the first Round Britain, being the first tri in the 1964 Ostar, getting foam sandwich going as a construction method.

    cheers all

    Phil Thompson
  12. rob denney
    Joined: Feb 2005
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    rob denney Senior Member


    definitely not a scam, we should have a 15m.50' hull in 4 days. We have a few boat builders coming, so have some hopes of getting the deck done as well. The iside is, apparently very accurate, and can have a peel ply finish if required. Actually, I see no reason why the table finish could not go on the inside and the outside be sanded (not torture boarded) and painted.

    As for the shapes available, we have a few small changes (very slight V in the bottom instead of a semicircle, and a miniscule amount of rocker instead of none) but nothing that the water flow will worry about. The foam, including the bulkheads and decks are being computer cut by DIAB, which opens up numerous possibilities for other shapes of hull, and implies that the interior is accurate enough for furniture to be pre cut and bonded in. There are some tricky shapes in the windward hull, which is much bigger, so we will get some more knowledge there.

    It is not just the KSS method of cutting and folding a small area of the hull that appeals. It is also the infusion. A 50m sheet of fair, and nearly finished material in a couple of hours on a table beats the hell out of any other technique. It also means lower cost materials (vinylester rather than epoxy, foam rather than cedar in some places) can be used with much less wastage.

    Bottom line is, I know about as much about it as you guys (maybe a little more than lazey), but Derek is a legend, in many ways a genius and in my experience incredibly honest and upfront, so I am prepared to give it a shot. Anyone who wants to see for themselves is welcome to attend.


  13. grob
    Joined: Oct 2002
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    Location: Cotswolds Waterpark, UK


    For the many who might be interested but cannot attend, due to being on the wrong side of the world, it would be useful if you could publish a report and some photo's, with Dereks permission of course.

  14. lazeyjack

    lazeyjack Guest

    some nice boats are built here, but GENERALLY speaking most are crap, wander around the marinas and take a Bo Peep,
    things are getting better though
    one boat I saw sells for trillions, the Grainger cat, long sloping transom , no sill on saloon entrance , no transom doors , welcome ocean roll on in

  15. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    Sounds great Rob, I'd love to attend but have time & budget constraints, $125A a day x 4 is pretty cheap infusion training considering the potential savings on material & labour on what can be an exxy learning curve. Definatly not a scam, I spoke to Dereck at the Sanctury Cove show around 4 years ago leading up to a infusion shot at Toowoomba( didnt get to go to that one either) he was doing & also found him to be upfront & honest about the boats & technique, & of course if ya got the knowledge your perfectly entitled to charge for it. As for the exploding boat I remember an article about the boat Phils described, also saw a training film that demonstrated the manufacture of nose cones using the technique, similar but less exciting as explosions was the stretch formed 20' Quanson trailer sailer built by Graeme Quantril & his Dad(founder of Quintrex) in round bilge alu- 4 stretched formed longtitudinal plates made up the hull skin, they did about 8-9 of them after investing in the tooling & were a sweet looking boat in their day. All the best with the proa infusion from Jeff.:)
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