Build time 40ft catamaran

Discussion in 'Multihulls' started by bluebox3000, Jan 8, 2014.

  1. bluebox3000
    Joined: Sep 2013
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    bluebox3000 Junior Member

    Well, essentially I just don't want to end up "boat" poor..... Without setting expectations and budget I think it is very easy to spend time and money and end up in a different place than planned.
     
  2. rob denney
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    rob denney Senior Member

    Bluebox,
    There are many reasons apart from enjoyment for building your own boat.
    The obvious one is the huge sense of achievement and pride it provides. Others include: You decide the level of fitout and finish and what is in it. You know how to fix it. You get new gear, so you know when things need to be replaced/maintained. You can plan a budget, knowing there will not be any surprises. You get exactly the type, size and layout you require and are able to build to sensible, proven scantlings rather than the overweight nonsense peddled by arse covering bureaucrats.
    How many of them were infused flat panel boats? Do they advocate ply because it is faster, cheaper, lighter or easier, or because it is what they know? There is a difference between not experimenting on your client's boats and not experimenting at all.

    I t was pretty obvious that you had never tried it when you suggested ply boats as a good starting point. Maybe buy ($150) or borrow a vac pump and do a small infusion using a sheet of glass as the table. You will be converted.
    Because the foam is cut from flat sheets, few if any full size patterns are required. It is easier just to measure, draw and cut the shapes on the foam. Then lay out the glass on the table and use the foam as a template to cut it. Easier and cleaner than cutting and joining bits of ply.

    I cannot think of any reason to use ply inside except the desire for a wood finish, and for that I would include a fancy veneer in the infusion. Silky oak or huon pine looks better than gaboon or doug fir.
    Edging ply is no easier than edging foam, but if the ply is not done properly it swells, rots and falls apart. Both are time consuming, frustrating and any misses stick out like sore thumbs. Any idea how many metres of raw edges are in your cat and how long they took to finish?
    With infusion, there are no bare edges to finish. They are exactly the right size and are completely glassed, filled and peel plied in the infusion, so are ready for paint with no more work required.

    Which curves on a multihull contribute to seakeeping? By far the most important factor for seakeeping is waterline length. A distant second are weight distribution, waterline width/draft (to avoid slapping/pounding), bow rake, prismatic coefficient and centreline to centreline beam. None of these are curves.

    Curves provide panel stiffness to thin panels, which can be achieved in other ways (furniture, thicker core, frames, stringers) all of which are easily included in an infusion at little or no extra effort/weight/cost, and looks.
    Fast, pitch resistant hulls are rockerless, with flat topsides. Rocker is added to allow them to tack easily. Round bottom hulls have marginally less wetted surface, as does rocker, but both are more than offset by the extra weight they add.
    Maximium space for least work and weight is flat bottomed hulls, which don't need floors or high topsides. Rounded edge decks on cruising boats are a recipe for a man overboard drill.
    If you can live with the unfashionable looks, an infused flat panel boat will be quicker to build, lighter, cheaper, and with far less of the time consuming, soul (and marriage) destroying fit out and finishing of a curvy boat.
    Non compound curves are very easy with infused flat panels, see the video in post #66. Compound curves can be built with conventional building methods. The more of them you have, the slower the build will be.

    I disagree. Production cruising multis are heavier and less well constructed than an amateur boat built conscientiously to decent plans. Pro built one offs are similar standard to the amateurs, not least because most of the pros were originally amateurs. I say this with experience of several hundred home and pro builders over the years and seeing production builders go broke because they could not match the performance and value for money of the home built boats.

    All the itinerant builders I know (loads in Aus and NZ, half a dozen currently working on projects in Europe) are skilled and hard working. They work as contractors, with no added costs (superannuation, sick leave, holiday pay, insurance, tax, etc) so are extremely good value. They are often cruisers themselves, so have plenty of input into what works and what doesn't and where quality bargains can be found.

    A problem with commercial (as opposed to itinerant) builders is they are generally unwilling to let anything out the door unless it has a showroom finish, which is bad for their image, but which they are not prepared to pay for. Consequently, the owner does. A self build, with contract labour can be finished to the standard and price that the owner wants.

    I do not see the relevance in using a 40+ year old 30' waterline cat (Fastback), a 35' waterline, 35 year old tri and a 30' waterline ply boat to compare with an amateur built new 40'ter. However, even those asking prices will be ball park for the materials cost for a basic fit out, workboat finish, foam infused 40' cat, and are higher than for a 50' proa.
    Self building is definitely not "a fools venture" for someone who is committed and realistic, unless there are other considerations such as shed space, available time, focus, etc.
     
  3. Baltic Bandit

    Baltic Bandit Previous Member

    Rob you keep leaving off the bit that at the "finish the owner wants" there typically is low to negative resale value.

    If I buy a used production or semi production boat for say $100,000k and spend $40k customizing it. I probably will be able to resell it for between $90k and $120k.


    If I spend $150k building my own, I will be lucky to resell it for $30k. as for curves that contribute to seakeeping? well entry shapes, prismatic and stern shapes for three. And done right, not one of them contribute excess weight and something like properly executed prismatic makes tacking and handing in crossing seaways much more agile.

    yes it is possible for a homebuilder to match and even exceed production boat quality. but that's rare. Most homebuilt boats in my experience, resemble Chinese knockoffs of Ikea furniture. Because most homebuilders lack the time and the $$ to actually finish all the work.

    You suggest that its "bad for their image" to have less than showroom finish. I agree. but that also cuts against the homebuilder who cuts that corner. it is precisely this lack of showroom finish that makes the homebuilt look lower quality than it perhaps is. And the age of the homebuild really doesn't matter.

    Self-building is not a fools venture for someone who understands that they are basically building a one-off, zero asset value item that may not work as advertised.
     
  4. groper
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    groper Senior Member

    BB - sorry you're wrong, the prismatic, entry and "stern shapes" are not compound curvature pre-requisites. Any value of entry angle and Cp can be found with purely single curvature surfaces.

    As you clearly havnt built a large cruising cat, and dont understand infused flat panel building methods, you dont understand what Rob was talking about when he talked about compound surfaces adding weight. The problem is caused by compound curves needing more fairing compound to fair them, more internal framing for flooring (its not nice to walk on a round bilge floor) more glue, filleting and tabbing for the said framing, and alot more work / fairing to spile every other peice of framing and cabinetry to conform to the curvy shapes. Every peice must be repeatedly trimmed in order to fit it.

    Believe it or not, there are many good reasons to build a boat, just because you cant see them doesnt mean they are not there. This discussion is not about "building vs buying used" so lets just put that to bed right now. A productive direction for this discussion to continue, is about the build time of a 40fter and the different methods, designs, and other factors which directly contribute to the build time.

    Without a doubt, Rob is spot on... compound curves take more time, the more you have the worse it gets. Plywood and infused panels both share a lack thereof which make them faster to build. Im surprised nobody has mentioned aluminium this discussion yet... ive seen a guy knock up heaps of 6m boats from CNC cut sheet aluminium in no time at all... i reckon this could be a very quick way to go aswell if the builder was capable of aluminium welding. I have never bothered to do a weight study, scantling analysis of such a boat however - they dont really exist AFAIK - 40ft cruising cats in ally? If the class rules are ignored and thus compared on a level playing field - ie they are designed in a similar way to private performance yachts in composites - im sure the weight could be competitive?
     
  5. DGreenwood
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    DGreenwood Senior Member

    Damn!... Please direct me to a well built 40 ft multi that is selling for 30K. I'll be on a plane by morning.
     
  6. nimblemotors
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    nimblemotors Senior Member

  7. bluebox3000
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    bluebox3000 Junior Member

    Valuation and depreciation is a different topic but needs to be a part of the consideration for any large build. I don't think people in general expect their homebuild to rival professional builds in resale price. I however don't think homebuilt boats depreciate any differently than professional built boats. A plywood boat may depreciate faster than other hull materials as it will attract more budget conscious builders building on stricter budgets.

    So the question remains how much of a discount does one need to give of a home built boat vs a professional built compatible boat? I'm not sure, but I would be surprised if it exceeds 50%. I would rather think it is in the range of 20-30% under normal circumstances.
     
  8. DGreenwood
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    DGreenwood Senior Member

  9. waikikin
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    waikikin Senior Member


    Everyday....... just look in the same spot?:cool:

    With a little stretch, a little paint & spruce up that boat would most likely sail circles around "most" production boats available today, oh & ditch the diesel & hydros for a single OB.

    Jeff.
     
  10. DGreenwood
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    DGreenwood Senior Member

    bb3000
    Take a look at this design.
    http://www.schionningdesigns.com.au/arrow-1200

    I'm not necessarily recommending the design...just showing you an example of what developable panel design can be. I can see a well executed design of that size and finished well, even by an amateur, to sell at well over 300k and considerably more if exceptional. And I can see 150 k doing this.
    Begin with careful planning. Hire a pro for part time help to get you on course and keep you there. He only needs to be around part time if you can arrange it. Then hire a grunt. Find a handy and intelligent kid that wishes to learn, say $10/hr. Have the pro teach you both the basics. The kid does all the clean up, sanding, teach him filleting and taping, sanding and fairing. The pro and the kid are going to take up 20 or 30k of your 150, but they will keep you concentrated on what matters and keeps the momentum. Some onsite advice from a pro will also considerably reduce your total man hours as well. Also it helps for you to have to meet their schedule as this reduces procrastination on your part.

    I really could not disagree more that production cats are anything like a real sailing cat. (that is if you keep in under a million $)
    Most production cats are waaayyy overweight, poorly built and are not what I call seaworthy. Most (not all) are doggy slow, pound in waves, and are overpriced gin palaces. Comfortable at the dock though. A well executed lightweight cat is worth far more to a cruiser that knows what he is looking for.

    Study really hard, plan really carefully, work really hard and you can build something of great value and you'll have a blast doing it. Fall down on any one of those things and you probably won't get it done.

    For what it is worth, (and I do love a lot of different building methods and materials for many different reasons) I think the infused flat panel method described by Mr Denney is an absolutely brilliant method for an amateur to build a real sailing cat. However, I also am a believer in going with what makes you comfortable or have some experience with. Richard Woods cats are a very reasonable route. Both methods will get you out sailing. And that is the point...isn't it?
     
  11. DGreenwood
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    DGreenwood Senior Member

    I agree. Tear out most of that weighty interior and work your *** off for 2k hours and you could have something better than a production cat but not nearly as light as something you could build from scratch in 4k hours.
     
  12. oldsailor7
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    oldsailor7 Senior Member

    Lots of "if" - "Buts" or "Wherefores" here.
    Nothing like actual examples.
    I built a Piver "Nugget". Cost $1500.00
    Sailed it for four years and sold it for $3,150.00
    Likewise a Buccaneer 24 for $2,500.00 Sailed it for two years
    and sold it for $4,500.00
    Built a Wharram Tehini-- less crossbeams and rig and sold it for $10,000.
    Built my Buccaneer 28 for $15,000.00, sailed it for two years and sold it for $32,000.00. Built another for a Florida chap and sold it new for $28,000.
    I also built three Buccaneer 33s in foam/Fglass sandwhich to basic fitout standard, I can't remember how much I sold them for----but Bruce B has one of them. If a boat designed by a recognised designer is well built, it will sell well.:cool:
     
  13. waikikin
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    waikikin Senior Member

    The thing is, you "could" go sailing tomorrow for roughly the same cost as rigging for a new boat & split a revamp into bite size pieces.... but for 6 months not bother & just enjoy so really decide what's needed.
    The boat is pretty cheap, the description says composites & ply, if the structure is mostly foam sandwich could be a great boat with some tuning up.
    Jeff.
     
  14. nimblemotors
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    nimblemotors Senior Member

    well of course you'd say that. OK, then this one:

    $17,000 oh, it is too light now right? It needs a sail, that is too much work.

    [​IMG]
    http://miami.craigslist.org/mdc/boa/4340863996.html

    (my thanks to Sand Crab. :)

    Sorry, don't mean to pick on you, there are cheap cats but they do need a lot of work. Building a new one is also a lot of work. More pride and you get pretty much what you want if you build.
     

  15. groper
    Joined: Jun 2011
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    groper Senior Member

    Yeah well, something like that doesnt cost $150k and 4k hours to build either... is it really that difficult to compare apples to apples??????
     
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