Build time 40ft catamaran

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

  1. oldsailor7
    Joined: May 2008
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    oldsailor7 Senior Member

    Nimble Motors.
    Quite agree.
    When I built my B24 Tri (with an unskilled helper), it took six weeks for the basic build, but-----
    It took another three weeks to fit it out and rig it to the state in which it could be sailed and raced.
    Actual logged time to build was 482 hrs. But REAL TIME,-start to launch- was nine weeks IE:- 1512 hrs.
    That's more than 50% more time, and a fact like this has to be taken into account when you are planning your build.
     
  2. david@boatsmith
    Joined: Aug 2008
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    david@boatsmith Senior Member

    We pulled the first Ariki hull in Jan 2012. We delivered that boat in May 2013. That was the hulls with beams, decks, houses,rudders,windows,hatches, bulkheads,floors,bunktops,and windows. This included the time to build the molds for the house,foredeck,aftdeck,beam tops, beam bottoms, companionway hatches, deck hatches.
    The 2nd boat we started in mid June 2013 and are almost complete. This is a completely well equipped boat. A pair of Ariki hulls is $57,000. A very simple Sail-away boat is over $300,000, a well equipped nicely finished boat runs over $500,000. That's all that stuff people are talking about. It all has to and or made get bought and it all has to be installed.
     
  3. bluebox3000
    Joined: Sep 2013
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    bluebox3000 Junior Member

    So sizing this up. Original thought was a budget for about 3000 hours for a basic 40 ft catamaran so if the hulls are about 15-20% and the rest of the structure somewhat more we are upon about 50% or 1500 hrs for completed external structure, painted, windows in and all internal glassing etc.

    So where do the additional 1500 hours go?

    Internal finishes 500 hrs?
    Mechanical and electrical tasks (outboard engine), galley, head fitout, steering 500 hrs?
    Rigging, winches and everything sail related 500 hrs?

    Just throwing out some numbers....
     
  4. cavalier mk2
    Joined: Mar 2010
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    cavalier mk2 Senior Member

    Less is more....what you don't put in will let you sail sooner is the essential message of KISS....(keep it simple stupid)

    It really is silly to compete with the amenities of land when the object is to be on the water.
     
  5. groper
    Joined: Jun 2011
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    groper Senior Member

    Nope... im at 1500hours now, and the outside is still not finish coated, nor non-skid applied... i still have the forward half of the boat hulls internal filleting and taping to do.

    This thread could go around in circles forever, best thing to do is read through some of the threads and blogs online, from people who are building the type of boat you would like. You can see how long things are taking, whats involved and decide if what theyve done appeals to you. There is plenty of builds located on this forum in the boatbuilding section, and more good ones at diy-yachts.com --- Im sure there are MANY more in all sorts of websites across the net.

    What you need to decide, is the method on which you would like to build, the design you wish to build considering the previous point, and what premises you have to build as this limits certain methods.

    There is no magic bullet - i for one wish there was - but the more detail and high level of finish you would like, the more time it takes. If you dont care about finish, and dont have bugger all fitout, its going to be pretty quick - but the resale value of it will be poor. So once again, time is money, how much time you have to trade is entirely up to the individual... The skill and dedication varies wildly from person to person also...
     
  6. catsketcher
    Joined: Mar 2006
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    catsketcher Senior Member

    You can make it simpler if you want. A larger sistership or our boat - a 13.5 metre version called Catchcry was built with almost no internals and then they went cruising. It was basically a shell with incredibly simple amenities inside. The when they came back after having kids grow up in the boat the owner John finished the inside to new so that boat sold for better than if they had finished it first.

    There is merit to this idea. I met one family with a schmick cat where the kids ate outside so they didn't hurt the upholstery. On a sistership to our boat the couple cruised for only a couple of months before they pulled the pin. The boat was immaculate but she couldn't relax and the grandkids were not as welcome as they could be - the upholstery again.

    You will need some internals. A 10 metre cat capsized in the 80s when the hull to deck join split. There were no reinforcing cupboards on the outer hull side.

    On another note maybe you should consider getting a computer cut design. Make all the tricky things at home in a small shed after work without the cost and hassle of renting a large enough one for the construction of the total structure. As I said before it was very nice to be able to grab a piece of interior and glue it in in my last build.

    When I was doing what you are doing - asking everyone I knew how long it took and how much it cost - a builder who became a good friend gave me some excellent advice. He said "Don't take the lowest figure - the one you want to hear. At least take the average of all of the figures you get".

    You will take longer than you think. A few months ago I came back from the boat shed (finishing the 7 metre cat) earlier than I said I would be. I ran up the stairs and said to my wife " Guess what? ". She asked me what was up and the realised it herself "A boat job took LESS time than you thought!" Clever woman my wife and it we worked it out that it was the third or fourth time in 4 builds.

    Do it if you really want to. I LOVE my boat and I couldn't have gotten it any other way other than building it myself. Maybe do what I did and go down and work with the best boatbuilder near you for free for a holiday. That helped me enormously get ready for my first build.

    cheers

    Phil
     
  7. Charly
    Joined: Dec 2009
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    Charly Senior Member

    500 looking for scissors that aren't gummed up
    500 climbing in and out the boat and about 500 hours of quiet reflection:p
     
  8. nimblemotors
    Joined: Jun 2009
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    nimblemotors Senior Member

    I have read through all the builds I can find on the internet.

    Everyone will tell you fairing/sanding is the worst task.
    Working in cramped spaces particularly when it is hot.
    Figuring out complex wiring or plumbing.

    What is easy is assembling things on a workbench.

    I know these are true from my own experience of building things for over 30 years.
     
  9. waikikin
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    waikikin Senior Member

    Having some level of organisation & even task specific tool kits can save a lot of time, A daily housekeeping regime(so stuff gets found) also materials being at hand & ready to go.... One place I worked at, for a short time, was a sh=t hole with 2" of stray chop over the floor..... puffs of dust rising at every footfall, most hand machines broken/blunt/no parts, standing machinery with no sharp tooling & many "frustrations", a mate had worked there in the past but quit after a management/ownership change... originally on order/deposit of a vessel the original proprietor had a list of every requirement down to fastenings for every thing, beltings/ply, you name it he got it in & loaded containers with it ready to go so no material hold ups, the original proprieter was able to work shoulder to shoulder with the build team & the boats(large game) went together in good time. After the change stuff came "just in time", no labour used for housekeeping, engines fitted weeks early(really only positioned to charge progress payment) that had to be worked around, workers scabbing through overs bins to "find" fastenings etc & a high staff turnover. So with a simple change of ownership & philosophy led to the demise of a great enterprise..... Scrooge killed Christmas so to speak.............

    Jeff.
     
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  10. luff tension
    Joined: Aug 2010
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    luff tension Junior Member

    Add at least another 500 hours interruption time for friends arriving to look, offering unasked for advice and also the mandatory social beers.;)
     
  11. rob denney
    Joined: Feb 2005
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    rob denney Senior Member

    Bluebox,
    The obvious way to save on the fitout is to leave bits out, but there are plenty of other things you can do if you are prepared to think outside the conventional box.

    On the boat in the video in post #66 we included the bunks, a full length bench and the ergonomic cockpit seats in the panels. The time savings are huge, as are the weight and materials savings. That boat has a round bilge, but flat ones are much easier to build and fitting floors takes a long time, on your knees or bent over. You can also have lower topsides. The more box like the boat, the more fitout savings are possible.

    As someone pointed out, the rig and deck gear takes a lot of time and money. Use an unstayed rig, with self vanging boom(wishbone or deep at the mast) and most of this (sheet winches, traveller, jib tracks, dolphin striker, fore beam, their fastenings and all the beefing up they require is eliminated.

    Daggerboards, their cases and in hull rudders are big time sinks. They need to be strong enough to hit things at top speed so they and their surrounds must be heavy. Kick up is a better idea, but still have the cases to be built, antifouled and fitted to the hull. Fixed keels remove your shallow draft, and are less efficient both up and down wind. An alternative to all this is leeboards or centrally mounted rudders and centreboard which have no holes below the water and can kick up in a collision. They also give you the ability to sail in much shallower water.

    Motors are a never ending cause of work and anguish. A single outboard on a tender which can be attached at the bow, with the dropped in to the water to power the mother ship is a great option if you set the boat up for it. It also gives you a large tender with plenty of grunt for exploration, amusement (skiing etc), load carrying and safety.

    If getting sailing for minimal work and cost are your prime requirements, then building a stock design will have all the time taking problems detailed in this thread.

    Barra,
    Absolutely agree about taping chines. A mate with a 12m double chine cat used a drum of resin and a couple of rolls of glass, just on taping; more than half a tonne added. Then had to fair it. Unfortunately, round bilge is not easy from flat panels unless you use parallel sections, in which case it is very easy, and need no fairing apart from the bow section. Including chines in an infusion is not hard and in many boats they are actually lighter as the core is simply left out, relying on the curvature to give it stiffness. Definitely less work and weight than taping panels.
    If you want compound curves, then flat panels are not the way to go.

    I know you didn't (otherwise you would not have written such rubbish about it), I just needed you to confirm it so people did not assume you knew what you were talking about when it was being compared with other methods.

    I didn't say you were either. Totally the opposite, when it comes to foam sandwich construction.

    Nor you did, my mistake.

    The 400 gsm is about 0.4mms thick. It is on the inside, so the biggest impact damage is probably from dropped cutlery. The outside is 600 gsm, about 0.6mm thick. 3 times thicker and more abrasion resistent than the 200 gsm on the plywood boat with which it was compared. Both would survive beaching on sand, neither would be much good against a concrete wall, but that is what fenders are for.

    What is the relevance of the French boats? Do you copy their laminates?

    As you have picked holes in the minor details of my post, can we assume that you agree with the important parts of it? ie, that infusion is easier, lighter and sometimes cheaper than ply? That building foam boats with non vacuumed segmented core is a poor substitute for doing it properly with vacuum? If you do disagree with any of these, please support it with numbers, weights, costs, etc, rather than repetitively accusing me of "putting words in your mouth" when I quote your prior posts or web page.

    Baltic,
    Curved hulls to resist torsional loads on a 12m cruising cat hull? The rudder and traveller loads feed into the aft beam, the shrouds into the main beam and the forestay into the forebeam. What is there to cause hull twisting in the skin? Building a curved hull instead of a flat sided one to resist torsion would be a pretty large misunderstanding of the loads and how they are resisted.

    rob
     
  12. John Perry
    Joined: Nov 2003
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    John Perry Senior Member

    Rob, I believe that there can be significant torsional loads on the hulls of a catamaran (or trimaran). At least, that is true for the type of catamaran or trimaran that consists of structurally identifiable hulls linked by two or more cross beams, it would not be true for those catamarans for which the hulls are blended into a large bridgedeck cabin structure since for those boats the cabin structure is likely to carry much of the torsional loading. Also, this would be less applicable to your style of proa where one hull is much shorter than the other.

    About four years ago I did a preliminary but reasonably detailed FEA analysis for a 10m LOA catamaran using ANSIS software. This was basically an open bridge deck design, there was a crew shelter at the steering position on the bridge deck but this shelter was not intended to contribute to the overall structure of the boat. Sorry I didnt keep any stress plots to show you and I dont have ANSIS loaded on my computer now, if I were to continue with this kind of work I would need to start again with Cosmos with which I have little experience.

    I modeled two load cases that produced severe torsion loads on the hulls. One was the situation where the boat is close to a lee bow capsize, with most of the weight of the boat being carried by the buoyancy of the forward part of the lee hull, the rest of the hulls being out of the water. I also modelled the situation where the boat is ashore in a boat yard with mast not stepped and the chocks under the hulls are badly adjusted so that the weight of the boat is supported close to the bow of one hull and the stern of the other hull, a relatively simple load case to consider for analysis. This load case may not seem relevant to actual sailing, but something similar but rather less severe would occur with the boat afloat and with the bow of one hull and the stern of the other on wave crests while the other corners of the boat are in wave troughs. These load situations certainly produced torsion on the regions of the hulls that were between the two main cross beams. For this design all the above water parts of the hulls were single curvature and intended to be made from flat panel material, only the underwater regions included areas of double curvature. There were longitudinal joints between the single curvature panels (i.e. chines, but I am not sure you would use that word for the upper regions of hull/superstructure ?) I think there may have been slight stress concentration effects at the chines, but this was not particularly significant. The stress concentrations that really stood out as big red patches on the stress plots were around the large entry hatches into the hulls and to a lesser extent around the fairly large windows, especially at the corners of these openings and despite these corners being rounded (apart from structural considerations this looks so much nicer than sharp corners IMHO). I tried several measures to reduce these stresses and ended up with enlarged corner radius together with something like three times thickening of the skin panels locally to the hatch openings.

    I was not including the window glazing in this analysis, whereas I know that engineers in the automotive industry certainly do include fixed window glazing in structural analysis and this is quite critical to the torsional properties of a car body shell.
     
  13. bluebox3000
    Joined: Sep 2013
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    bluebox3000 Junior Member

    Regarding the skin. Is the 600 gsm (18oz/sq ft), is that just one layer of cloth or more?
     
  14. groper
    Joined: Jun 2011
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    groper Senior Member

    John, for these kinds of stress concentrations around openings on lightly skinned sandwich multihulls, we simply use some uni directional "rope" which follows the perimeter of the opening. This is much more efficient than increasing the skin laminates.

    There is no problem with handling loads on thin skinned multis which only have single curvature... There are countless examples of very successful multis which prove it...
     

  15. groper
    Joined: Jun 2011
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    Location: australia

    groper Senior Member

    1 layer of said weight...
     
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