Quick building strategies

Discussion in 'Multihulls' started by simon, Oct 17, 2007.

  1. rapscallion
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    rapscallion Senior Member


    I bet you post on sailing anarchy... with a rapier wit like that you have to be careful.... you're liable to poke your eye out.
     
  2. waikikin
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    waikikin Senior Member

    Raps, dunno if thats rapier wit, just sounds like sh=t bagging to me, probably one of the most unhelpfull aspects of the Oz marine industry & all too easy to get dragged down by, the perpetrators let themselves down by their involvement, rather encouragement & support are much better & more valueable to all involved in my estimation. Regards from Jeff.
     
  3. Alan M.
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    Alan M. Senior Member

    Most people will push the building method they are comfortable with. I haven't seen the KSS system at work so I can't comment on it, except to say that I wouldn't build using polyester or vinylester resin, which seems to have been the resin used in the recent KSS workshop. For such a small extra investment compared to the cost of the boat I would always choose epoxy.

    I do have experience with building in Duflex, using Bob Oram's technique - right side up, in female frames. I can probably reel off fairly comparable hull build times to KSS.

    In 8 days after starting from scratch, including setting up a strong back on a sloping dirt floor, and setting up the temporary frames, I had all the Duflex sheets pressed together, and a complete 44 foot bridgedeck catamaran hull along with half the bridgedeck floor built, ready for bulkheads to go in. If I had been pushing to get the hull turned ASAP, I could have done that one day later - after installing a couple of bulkheads.

    Duflex requires relatively very little fairing - it naturally bends into very fair shapes, and all the fairing that is needed is to blend the tapes in.

    You could have a pair of faired hulls, and a bridgedeck floor joined up, in probably less than six weeks if speed was your aim.

    But for a fully fitted out 44 foot cat you are still going to be looking at probably 3000 hours as a minimum. If you want a decent standard of finish and fitout, then closer to 4000 hours for sure.

    I would expect that even if KSS saved you some time building the hulls, your'e still going to be up for similar total hours for a similarly fitted out boat - I'm sure it is simpler to fit out a hard chined, flat keeled boat which requires no floors, compared to a round bilge boat.
     
  4. Fanie
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    Fanie Fanie

    I feel the same as well. If one goes into production I would think the KSS would become much more attractive, and especially on large items.
     
  5. rwatson
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    rwatson Senior Member

    We are getting some heated comments here, and pride is always feature of professionals, and I learn a lot by the points raised. But I am a bit put off by the last bit of innuendo "no idea regarding fairing " - I would be much more interested in facts like - "the keel line showed wavy lines on xyz boat" or something concrete. Its a lot more usefull to understand a point of view if specific examples are shown or discussed. I have read one of Robs articles where he specifically spent less time on fairing to get a demonstration hull ready for testing by a certain date, so there is always background info to understand as well.
    But back to the subject - quick building, I must admit as an interested observer (potential user of some method or other) the flat panel method makes the most sense so far, based on the hassles of getting any type of "goo" to to stay put on a non-horizantal surface. But the comments on getting the internals in place before putting a hull on impress me too. It makes just as much sense to finish and locate key bulkheads etc before the hull exterior - like the methods that use some of the frames as permanent component. Fiddling around in confined spaces, once again on non horizontal surfaces, sound like something to avoid, if possible.
    I am interested in web sites that show a step by step applications of any type of methods for evaluation, but obviously people like to protect their good ideas. So I will keep on getting bits of advice here and there, sifting the discussions - and sifting the rhetoric and the facts.
     
  6. doug kay
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    doug kay Junior Member

    Could someone just explain what KSS is exactly, I've googled it but without success. I take it it is building with foam in one form or other. Thanks. I don't think it helps if writers opinions are simply dismissed or ridiculed, let's keep it friendly and we'll all learn something and you may encourage others to take up this wonderful hobby.
     
  7. doug kay
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    doug kay Junior Member

    Thank you for that excellent post rwatson. I have an idea which may be useful in cats. and a way to avoid the weather hull lifting and that is water ballast. Suppose a false bottom was built into each hull and filled with water it would weigh nothing under normal sailing conditions but should a hull try to fly then? Discuss please.
     
  8. rwatson
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    rwatson Senior Member

    Doug - the info on KSS was dropped in a few pages ago
    http://www.kelsall.com/methods.html
    compliments Yipster
    The water ballast idea is perfectly viable, has been used on many production yachts already - but is probably going to be best dealt with in a new thread on that specific subject, - it certainly won't contribute to fast production of cats.

    To take the fast building subject further, I found a site
    www.scrumble.com.au
    building a Bob Orram 44c, very comprehensive visual description of the techniques, replete with commentsa like "spent days re-fitting panels until it fitted etc"
    It reminded me of just about every other building method I have read. Things are better though in that there is no overhead glassing involved , which was certainly a feature of at least earlier KSS techniques.

    Both techniques have in common flat panel preparation and then assembly, though the KSS technique of moulding the foam in situ is a swish idea..

    I am getting the feeling after considerable research that the fast boatbuilding technique may end up being function of the style and numbers of boats (multiuhull, mono, one off, production). For example - MacGregors would seem to have the asembly line technique down to a fine art, and he is very wary of soft panel foam cores. But for one off builders, doing plugs for GRP would be a waste of time, and maybe weight becomes a bigger issue for some boat designs than others.

    Those people that commented on price being a function of ease of build have a great point. The proof would certainly be in the price - to coin a phrase.
     
  9. Alan M.
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    Alan M. Senior Member

    One of Bob Oram's designs (that I know of) has provision for water ballast.
    The "Mango" 38.

    Regarding the "Scrumble" website - Tom is doing a superb job of his boat, but I don't think a super fast build is his main goal at this point in time, so it's probably unfair to judge how fast Bob Oram's construction method can be based on Scrumble.

    I had no difficulty in fitting at least 2 bulkheads in a day - coved and taped on both sides. They don't need much trimming at all, in fact I learned from someone who is currently building his third 44C that if one of the pre-cut panels isn't fitting well, you have made a mistake somewhere.

    Neil of Coolcats has got the build technique pretty much nailed down, and he gets his hulls together andfaired VERY quickly. Most of us doing a one-off like me, spend a lot of time thinking about our next step, and I have to say I do take some time to simply step back and enjoy the experience.
     
  10. doug kay
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    doug kay Junior Member

    Alan, I suspect it's a matter of whether you're building one boat or several. For production runs it pays to buy the equipment to cut down labour costs but for the backyard builder this isn't viable. I just can't understand why posters get so worked up about it, ya pays ya money and makes ya choice.
     
  11. rob denney
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    rob denney Senior Member

    G'day,

    Bruce, My fairing cv includes the English 12 Metre Crusader ('87 Americas Cup), Ondine 4, (80' maxi), and more plugs, moulds and boats than I can remember. I have sold tons of bog to most of the gig Australian commercial builders and hundreds of cedar boat builders, then stood back and watched them turn most of it into dust. I was also involved in the development of the Powerboard, the only mechanical fairer I know of that actually does a reasonable job. I have far better things to do with my boat building time than waste it giving my boats a show room finish.

    Raps and Jeff, Ta.

    Alan M, A huge proportion of the boats in the world are built from polyester or vinylester. Used properly, they are excellent materials. Proper use is using a mould, and ideally infusing or at least vacuuming it. Secondary bonds and hand lay up, I agree, epoxy is best. Speed of cure is also a plus with the esters, you don't spend time waiting for things to cure. However, they stink, and styrene is not good for one's brain. Epoxy, on the other hand, is an allergenic, and once it gets to you, your building days are over.

    8 days for a hull and half bridgedeck is impressive, you have my respect. I have seen Scrumble and they are doing a great job, but there is still a lot of fairing in of the tapes required if a show room finish is required. Chined boats are definitely easier to fit out (minimised if the fit out is computer drawn) , but don't perform as well as round ones. Probably not an issue for most cruisers.
    rwatson, there are some pictures of the latest KSS build technique on the yahoo harryproa chat group photos section. You will need to join to see them. Any questions, please ask.

    doug, few large cruising cats have hull flying problems, so water ballast is not required. If you do fit it, remember that everything has to be beefed up for the max load, resulting in a heavier boat, which will be slower when the ballast is not used.
    regards,

    Rob

    regards,

    Rob
     
  12. Fanie
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    Fanie Fanie

    One of the time problems is always the time you take to get the glass wetted and applied quickly. Ideally you'd want to glass a whole structure out before any of the glass started to cure which makes the best structural bonds wether overlapped or layered.

    I always had the idea that these old washing machines that uses two rubber rollers to dry the washing out or a similar machine should work perfect for wetting the glass out.

    If the bottom roller sits in the mixed epoxy or polyester and the mat is rolled through it, it could wet the mat out as well as squeezing the excess resin back out very quickly.

    The pressure of the top roller if adjusted could determine the amount of resin in the mat. The wetted mat can then be rolled up on a wide roller and rolled off on the item to be glassed.

    Using a software like touchcad that can draw the mat in shapes that can be CNC pre-cut, it should only be a formality to quickly wet the mat and place it in position.

    A CNC machine with a roller cutter (or maybe laser) could pre-cut the glass in the correct sequence and shapes faster than you could apply. Pre-cutting the mat and stacked in the right sequence would of course be better. Software nesting of the pieces would save material losses.

    I would imagine one may be able to glass a complete boats structures in a single day this way, using only a small team of people. Ideally something like a hull would be easier to do if it can be turned.

    One person keeps the mixed resin on level.

    Two feed the mat strips or pieces into the rollers, and rolls it up on a roller as it is fed out, and then rolls the wetted glass onto the surface.

    One person co-ordinates the placing of the wetted surfaces according to a worked out sequence and position schedule.

    One or two or three people roll the air out of the applied material.

    Using a second pair of guys they could also feed and roll the mat up while the first two guys are placing their mat.
     
  13. Alan M.
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    Alan M. Senior Member

    Rob, the difference in wetted surface area between a multi-chine hull and a round hull is small. Balanced against the fact that to be habitable the round hull will need floors, adding significant extra weight, whereas a flat keeled multi-chine may not, (Orams up to and including the 44C don't have floors) the performance difference is probably too small to measure. It's even possible the floorless multi-chine may have an advantage. We raced a home-built, fully laden Oram 38 Mango against a resin-infused round bilged Fusion 40 (which had a vastly bigger rig, and much higher tech sails) at the recent multihull rendezvous, and absolutely thrashed it. In one race which took us 4 hours we beat them by over two hours. There are photo's and an article in this months multihull world - you can see the huge difference in rig size and sail area, as well as the carbon sails on the Fusion vs our dacron ones. A multichined boat won the division.

    It's true there are thousands of poly and vinylester boats around the world. There are thousands of boats with osmosis too.

    A friend of mine is building using infusion with epoxy - it's working very well for him. If I were going down the infusion path I would use epoxy too. In fact, the infusion technique would largely eliminate the main concern with epoxy - that of becoming intolerant to it, because of the minimal exposure.

    There is also the consideration that the esters release styrene for several years - inside the boat, where you live - and as you say, it's not good for you.

    Building your own boat is a major investment in time and money. I just wouldn't use esters - the savings are not worth it IMHO. But everyone has different priorities.

    BTW getting one hull and half a bridgedeck together in 8 days wasn't any particular kind of feat - that's just how quickly it happens using Bob's kits.

    Oh, and good luck in the solo transpac - I hope you do very well. Cheers, Alan.
     
  14. waikikin
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    waikikin Senior Member

    Fanie, what your describing is called a fabric impregnator, have a look at the pro set site, they got a nice 50" model on there, my dad made me one pretty similar & we intend to travel it over our jobs. Your a clever bloke, cause you've independently invented it too. Maybe in our case infusion might be a process that helps in the future too, which hopefully wont disapoint dad after the impregnator effort- should still be usefull on other stuff as well & he hates goo with a passion, & reckons epoxy will cross a room just to make him sticky! All the best from Jeff.
     

  15. Fanie
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    Fanie Fanie

    Hi Jeff, what's the pro set site ?

    Traveling it over a job is a good idea. I had the idea one could use a cart with hoist on a track kind of to get you into high places...
     
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