Considering Homebuilding a ~50' Catamaran

Discussion in 'Multihulls' started by Iridian, Jun 10, 2021 at 4:17 PM.

  1. Iridian
    Joined: Jan 2020
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    Location: MD

    Iridian Junior Member

    Lets get it out of the way. Yes, I'm an idiot, most boats won't get finished, cost way more then expected, and take way longer then expected, buying a used boat is a better idea, the only reason to build a large boat is a labor of love, it's better to go sailing then bury yourself in fiberglass dust, and resale value will be terrible.

    All that being said....

    In 4-5 years, if I'm still inclined and have spousal support, I am thinking about home building a large catamaran.

    In looking at designs, I think either a Schionning Arrow / G Force 1500 or a Grainger Raku 52, best fits my needs.

    Why go so big?
    1. I'm tall, 203 cm. I want a boat with sufficient standing room to stand up straight, but not too much freeboard relative to its length.
    2. I believe that catamarans don't truly hit their stride in the 35-45' foot range due to freeboard, deck clearance, and hull width, especially with performance hulls.

    Why home build?
    2. I've had enough of playing video games for 3-4 hours a night on weekdays, and 6+ on weekends. I want to do something constructive with my time.
    3. My work is on the computer, all day every day, and very its all very abstract. I want to build something with my hands.
    4. I love sailing, and I love catamarans.

    Guesstimate Budget/Time to build/Other?
    1. Estimating 400-500k USD completed build.
    2. Estimating 6-10 years at 25 hrs/week.
    3. Intend to have a permanent building next to my house with sufficient room, ventilation, and heating to enable largely comfortable year round construction.
    4. I've limited composite experience, and intend to gain it throughout the next few years in various projects.

    All that being said, two questions for you guys at this time:
    1. What books/planning would you suggest in the next few years as I continue to solidify the idea and plan?
    2. What risks do you see, excluding motivation, and how would you mitigate them?
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Is a sailing or a power cat? There are other aspects that will make a huge difference. For example, is there a large salon in the bridge, how much beam in the hulls, what kind of cabinetry and finish? The interior is more than half the cost for a nice, not luxurious, finish.
     
  3. Iridian
    Joined: Jan 2020
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    Location: MD

    Iridian Junior Member

    Definitely a sailing cat. I'd like to keep the weight down for performance so minimizing interior joinery and woodworking will be part of the plan.

    In both designs, the saloon is sizeable but not huge.
     
  4. kapnD
    Joined: Jan 2003
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    Location: hawaii, usa

    kapnD Senior Member

    Half a million and ten years?
    Better to just steal a boat you fancy, and sail away in her till the law catches up with you!
    Then write a book about it while you’re in jail.
    There’s no fiberglass itch in jail...
     
    redreuben likes this.
  5. Rumars
    Joined: Mar 2013
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    Location: Germany

    Rumars Senior Member

    With your height the only option is to go custom. If you look closely the G Force 1500 has 1.95m standing height in the saloon, and 2m in the hulls, wich means you can't stand up straight inside. I doubt the Arrow has more headroom. Even if you find a boat that has at least 2.1m everywhere, you still need to redesign the complete interior, it won't fit you properly otherwise.

    A flat panel kit boat does not require big composite experience, everything is prelaminated and precut. Your job is to tape the seams, then it's a fairing orgy. For that you should invest in the best tools possible. The interior should also be designed as a precut kit, no complicated joinery needed.
    If a more rounded hull is desired, then infusion on a stringered mold with thermoformed foam is not very difficult.

    Best advice I have is to downsize the interior and systems as much as you can stand. Empty hull space is cheap and makes the boat better, so plan on a 40ft interior on 50ft hulls.
     
  6. oldmulti
    Joined: May 2019
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    Location: australia

    oldmulti Senior Member

    Please look at the following web pages that may give a hint of the structure you could be building. The cat is a large, complex and has hundreds of parts to it. Each has to be done well. My guess is if this is a home build you are in for 10,000 hours and 10 years. Even going to a 45 footer will reduce your build time, expense etc significantly. An for those who suggest the page numbers should be specified please look at the web address which shows the page number.

    Multihull Structure Thoughts https://www.boatdesign.net/threads/multihull-structure-thoughts.62361/page-38 Item 570
    Multihull Structure Thoughts https://www.boatdesign.net/threads/multihull-structure-thoughts.62361/page-39 Item 573
     
  7. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    People shrink (in height anyway) as we get older, in 10 years you will be an inch shorter, and won't need quite as much head clearance !
     
  8. Iridian
    Joined: Jan 2020
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    Location: MD

    Iridian Junior Member

    @Rumars
    I think the raku may have the headroom but I'm not sure. Either way I'm probably going to need to pay the designers to stretch the boat vertically just a tad. 100% agreed on the minimalist interior, I feel like a lot of the wood veneer and joinery ends up looking sort of like a mobile home anyway. I intend to use cnc cut kits wherever possible.

    @oldmulti
    Thanks for the links. If I wasn't so darn tall I would definitely go for a smaller boat.

    I wasn't aware the furniture was part of the structure. I'll need to think through that as I work out the interiors. Do you think the budget is reasonable for a boat of this size?

    @Mr Efficiency even at 200 cm I'm probably still going to suffer on most boats lol. Gotta keep the back intact.

    Any book recommendations also?
     
  9. oldmulti
    Joined: May 2019
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    Location: australia

    oldmulti Senior Member

    Iridian. Budgets are hard. I know people who can negotiate very well an can build a boat for 60% of a guy who just says "I need that" and will pay whatever. Also there are people who are directly importing EG good PVC foam from China at 60% of the price you pay for it locally. This stuff requires time, skill and an accurate bill of materials. Also there is a tendency for EG Schoinning to sell "plans" that require you to buy a full boat kit from a certified source. As stated on Schoinnings web site you cannot build certain designs from his $20,000 plans unless you have the kit. If you are good at negotiation and do not have to much luxury, electronics, top notch sails, deck gear etc. $500,000 may see you to a launch.

    Really understand your needs and you may find a designer who will slightly modify an existing 45 foot design for EG $2000 with a higher roof line in the hulls and bridgedeck. This can save you a lot of money and effort. There are 45 foot French production cats that have a lot of headroom so its possible.
     
  10. guzzis3
    Joined: Nov 2009
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    guzzis3 Senior Member

    No one ever likes my ideas but I'll chuck them in anyway.

    Sailing Catamarans - Nimbus - Round bilge bridge deck cabin cruiser http://sailingcatamarans.com/index.php/designs-2/5-catamarans-over-40ft/188-nimbus

    2m headroom throughout at 40'. Also I would guess Mr Woods would approve a small increase in headroom if you want more. Say 6". He might even offer a chined version if round bilge scares you but hull skins are not - ever- the problem. It's the death by a thousand cuts in making boring bits endless fitting out and the subsequent $ for rig motors and fitout.

    If you are determined to have longer hulls then consider an open deck cat. The hulls will have ample space for all living accommodation unless you belong to a nomadic cult and you get all the benefits of long waterlines without the added cost of the bridgedeck cabin.

    If I was your height this is what I'd build and just jack up the height maybe 10%

    Sailing Catamarans - Meander - open deck performance cruiser http://sailingcatamarans.com/index.php/designs-2/5-catamarans-over-40ft/189-meander

    Build it in resin infused foam glass flat panels keep the fitout light (foam sandwich interior) and it'd sail like a demon.

    2c..
     
    gonzo and bajansailor like this.
  11. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    It says 2 meters minimum headroom. It would be interesting to know what the average is.
     
  12. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    It's not enough to raise the deck a little and call it done. The furniture all needs redimensioning and most of it is structural. A simple example, beds, bunks, setees and cockpit benches are usually not over 2m/80 inches long, but the OP needs something at least 2.2m/87 inches. This can change bulkhead spacing, wich alters span, wich alters panel thickness, etc. Same thing with seat height, he needs them taller, so now the stringer position is altered.
    Of course he can live with poorly dimensioned furniture, I am sure he encounters it daily, but if one spends half a million and countless work hours on something, it should at least fit him properly.
    If I look at Schionnings prices and add the charge for a custom interior, for that money you can have almost anyone in the world do a custom design, plenty of them more famous.
     
  13. comfisherman
    Joined: Apr 2009
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    Location: Alaska

    comfisherman Senior Member

    I can sympathize on the height. While not as tall as you I'm only a few cm off. In a fleet of 1800 Bristol bay boats only 5 from one obscure builder had a ceiling height that was tall enough to fit me. My new build is specifically designed for that after more than a decade hunched over, it's worth it. Does kinda mess with lines of a lot of boats. Mine definitely had a bit of a funky look to it. My grandfather has a similar issue with one of his first boats. There is a grainy black and white photo from 1970 of a bunch of delta seiners tied up abreast and his was pretty easy to pick out....

    I'll say this as someone going from alloy to glass and doing a minimalistic no wood approach...

    Less wood is longer when its s one off. Tabbing and prep work takes forever, the end project is awesome but it does take a long time. Having put together aluminum boats and made the switch to glass, its glacial to do one off glass boats. Worth it for me, but it's a fair assessment worth noting.

    A key component to really think about is cost creep over time. Your budget is solid for 2019, 2020, and probably accurate for up to march 2021. Cost creep from regional inflation has global impacts on prices. In 2008 I needed to do a repair project that was rather substantial. But China was gobbling up steel prepping infrastructure for the Olympics and steel was stratospheric in price. We nursed it along for years waiting for it to come down. Did the same thing with composites a few years later when the windmill boom sucked it all up and made the price sky high.

    Key is to really be careful about managing plans and design changes over time. In 2019 my project started we pre bought most components. Had a fun health battle that took me outta the game until this spring. We switched some minor design ideas in the interim and it required the purchase of some extra thru deckfittings. It was a bit astounding to compare the prices of things purchased not 17 months apart from the same source. Magnify that across 10 years and the budget can go out of control.

    Can't speak to the other aspects just wanted to give some feedback on some of the unforeseen potential pitfalls.

    My reccomendation is this, and is advice given to me from an older wiser builder. Find plans for a small dory or tiny cat. Then try and adapt it to your size by modifying beam or even just seat height and gunnel height to compensate for your height and weight. Then compare the time, money, and weight it ended up costing to build vs. The estimated average from the standard plan. It should give you a bit of an idea on how hard it is to adapt, fair, hit weights, and work with materials. For a few thousand in materials its worth the education, and you have something to play with in the decade while you torment yourself with glass dust.
     
  14. Iridian
    Joined: Jan 2020
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    Location: MD

    Iridian Junior Member

    Thanks a lot for all the thoughts guys.

    @guzzis3 The idea of doing a smaller boat is certainly appealing, but if I'm going to be spending a huge portion of my life and a big chunk of change, I really want to get exactly what I want, or it's really just not worth it. It also takes me back to my principle complaint with small cats. The small form factor just isn't enough to fit everything with any decent level of performance, especially since long term I'd like to live on board this boat permanently.

    @oldmulti a kit is definitely on the table, though I expect the markup is pretty insane. I'd rather get just the plans and shop around for the foam and cnc shop. What are your thoughts on a modified Grainger Raku 52? The lines look a lot easier to build and I believe the plans are cheaper as well. Not sure what the height is, so it'd probably still need modification. It's supposed to be an evolution of the Chincogan 52.

    @Rumars I really hadn't realized how much of a mess my height would make this. I'd put some thought into buying a hurricane damaged yacht and trying to repair it, but in watching all the videos of people rebuilding the, the hidden damage, tear outs, amd potential structural issues scared me off. Even excluding that, I'd have to slice off the saloon roof and raise it, and be stuck with the rest of it. In thinking about everything you are mentioning. I think I'll definitely need to find a designer willing to work with my specific needs.

    @comfisherman , thanks for all the info. I've looked into aluminum boats like the Bruce Roberts 1500 Eurocat and the Mumby 48/50. Originally id thought about going that direction and taking some welding classes at my local community college, but a couple of things scared me off. The biggest few were galvanic corrosion, insulation, and portable repairability. I want this boat to last until I'm too old to crank a winch if I'm going to put this much time and effort into it. I want to sail north, and see the fjords and other desolate places not roil in the caribbean 24/7/365. And the logistics of bringing a welder on board are a little rough compared to glass. Excellent point on the inflation index. I'm hoping my salary will keep pace but that's probably a vain hope. Will have to put some thought into it. I'm hoping to use the next couple of years to learn enough and solidify the design enough that I don't make two many changes once the build starts, though that's also probably unrealistic. I already have a hobie miracle 20 I use for leisure sailing, but I've been thinking of building a composite canoe, truck shell, and motor mount to get my hands dirty. I should probably find some other big projects as well.
     

  15. oldmulti
    Joined: May 2019
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    Location: australia

    oldmulti Senior Member

    Grainger is approachable and will modify plans or do a slight redesign and call it EG Raku 54 etc. Grainger's approach to flat panel with separate rounded bottom is good and helps with the speed of build. BUT be warned measure the amount of joining tapes you will have to do with flat panel components, it will measure in the 1000's of feet. Each one of those tapes will need to be filleted, hand glassed, compressed, sanded clean and faired into the surrounding structure. This is a pain as comfisherman is indicating. In some situations its easier to build a throw away mould and layup a eg forward deck structure with hatch indents and reinforcing areas and infuse 2 of those parts instead of doing a bit by bit build up twice. Tomorrow in Multihull structure thoughts I will do a piece on simple female moulding which may give an idea.
     
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