Considering Homebuilding a ~50' Catamaran

Discussion in 'Multihulls' started by Iridian, Jun 10, 2021.

  1. TANSL
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    TANSL Senior Member

    So why you wrote : "That's not so"
     
  2. comfisherman
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    comfisherman Senior Member

    If only we could ascertain from the title the OP's prefference.....


    OP has a realistic budget and time frame as well as a realistic age to have the energy for such and undertaking. Having been 25 and building and working boats family/relationships coalesce around it in a way that's less common at an older age. Being 6'7" does make for a tough one. I'm two inches shorter and cannot imagine being bigger.

    My honest opinion is this. You sound like you're in it for the long haul, and have more realistic expectations than most who grace these pages.

    Compile the features you like, start traveling to ports as we return back to normalcy and start to chase down the designers of one offs you see that catch your eye.
    The investment in a one off design may look a bit off putting upfront, but amortize it over 50 years of use tailored to you and it's a wash. Even if it takes some time to find a good fit on the right architect.
     
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  3. guzzis3
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    guzzis3 Senior Member

    Yes there are so many reasons to prefer a smaller boat. I'd never go over 10 meters, and have serious reservations about over 9 meters. There are so many reasons apart from cost to build and maintain such a boat. Deploying an anchor alone when just overtaken by a storm, approaching a dock especially in any sort of current or strong wind, manhandling the rig. Everything gets exponentially bigger, heavier and harder.
     
  4. guzzis3
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    guzzis3 Senior Member

    Hi,

    Be aware I am blind so I may mess up editing this post. Sorry.


    Fair enough. Also the cost isn't the killer if you spread it over many years.
    Richard Woods, easy mistake. He is very patient. If you keep your email concise I am sure he would be happy to answer you.

    Trimarans are more work and money to build but in the sizes you are considering the Tristars offer 3 seperate living areas. I don't know how many people you plan to take along, you may have a clutch of kids before you finish. Don't build in plywood. See the many other threads here on that.

    Glass is cheap. Foam is expensive, but from utek it becomes similar to plywood. Timber requires epoxy which is expensive. Polyester resin is the cheapest but osmosis is a worry along with water saturation. Vinylester is a good half way option.

    It's a death by a thousand cuts. The hull is stop stop GO. Time to set up but then big big slabs of hull skin and bulkheads get done in short order. Then you join them around the structural bits (beams etc) and it's done.

    Then you have to position and drill every hole. Get plumbing to join up. Get a nice edge on EVERY little bit of visible interior. The fridge is slightly bigger than you assumed now it doesn't fit...thinking swearing and rework. You can't quite get that bit of wire to go where you need it, you cut a hole a little too big and have to fix that...

    A longer boat is theoretically faster and rides a bit nicer but apart from cost and time to build everything gets exponentially heavier. You have been at sea for over a week, it's blowing a gale, it's night freezing and your stuffed. You have to go on deck to unravel sails or a shroud has broken. Your chances of breaking something or hurting yourself are high,and the consequences on a huge boat are that much more serious.

    The reason I've always felt a 32' cat is my maximum is that precise reason. It's night, I've been overtaken by a storm but I made it to harbour. Now I have to down sail and anchore alone because the crew is sick and exhausted. I reckon I could manage that on a 30ish foot cat. A 40 would probably be beyond me.

    Remember a 40' cat isn't 1/3 bigger than a 30'. It's well over twice as big. Proportional to weight not length. The 50' your talking is probably 5X the boat.

    6' headroom in a 30ish bridgedeck cabin cat is common now. To maintain those proportions you want 7/6 x 30' or 35'. I'd probably got to 12m/40' and it would be prettier. As above a 50' cat isn't 25% bigger it's probably half again or something. For example the tristar 51 is 25000lbs the 41 is 12000lbs. Twice the boat, twice the work, twice the money.

    As I suggested before unless your taking a cult along with you this boat will have fantastic amounts of space. Build big hulls, 40' long 7' inside. They will come out about 7 or 8' wide. Probably 240 sqf of floorspace each. Plenty of room for bathrooms big beds, dining table galley workshop... steam room table tennis cinema... and leave the deck open. Less money time and you can play baseball when weather allows...

    And you can always add the bridgedeck cabin later if you feel cramped in the hulls.

    Anyway...
     
  5. guzzis3
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    guzzis3 Senior Member

    I'm sorry I don't understand this ? If you are quoting me could you show me where I wrote that ? I was blinded by stroke last year and struggle to read.
     
  6. TANSL
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    TANSL Senior Member

    No, I can't, sorry.
     
  7. Ad Hoc
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    Ad Hoc Naval Architect

    Sorry to hear guzzie, i hope you can recover?

    As such, I fear you have misread....since the post/replies from Tansl being noted refer to the poster Gonzo, not you, as Guzzie.
    In your current state, sadly I suspect you have misread this.... so I would not worry.

    It would have been nice of Tansl if he could have noted this - rather than the terse reply.
     
  8. TANSL
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    TANSL Senior Member

    Why is it remarkable, or reprehensible, to give a concise answer? What more can be said?. I could, of course, say a lot of things and embellish them with my language skills (which I lack) but all that rhetoric wasn't going to add anything substantial to my answer. Not for much talk is there more reason. Guzzis3 simply did not say that and therefore I cannot point out where they did. But please, if that's okay with you (and if not, too) let the thread run through its normal conduits. My response to guzzi s3 has not been to try to get this thread twisted, imo.
     
  9. guzzis3
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    guzzis3 Senior Member


    Thank you for the clarification. I apologise for my mistake.

    No. Virtually no chance of recovery. The aphasia improves a bit if I practice my reading daily, but I only improve so much even with practice.

    I'm not looking for sympathy, I just explain my situation so when I make mistakes etc I hope people will understand. Doing my best.
     
  10. Ad Hoc
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    Ad Hoc Naval Architect

    You have nothing to apologise for, you did nothing wrong.
    It is clear that your stroke has left you visually impaired and mistakes can easily occur... such is life.

    It is sad the other poster is unable to comprehend this side of humanity and only sees this as an issue about him.
     
  11. Iridian
    Joined: Jan 2020
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    Iridian Junior Member

    @guzzis3 , appreciate all the information, and I'm impressed with your ability despite the impairment. Tons of good information in this thread! Thanks for the correction for Richard Wood.

    Its good to know where all the time sink will be. Seems to really be a case of knowing your requirements before you start the build. Good thing I have some time to think over it!

    I've thought trimarans a bit, watched some videos on the Neil trimarans, and the Rapidos. Honestly, not a huge fan. I like the opennes of the catamarans more than the rapido style of trimarans, and I'm looking for more performance then what a neil will offer. I'm also concerned about the even wider boat in slips, as it seems a lot of slips are charging by the square foot. Lastly, I don't like how trimarans can slap from ama to ama in waves at anchor.

    With a 40' cat and hulls at 7-8' wide, even considering a narrower hull below the waterline, say 6', we're still under the 8:1 length to beam ratio for decent performance, right?

    Utek looks like a good resource. How truthful are their performance claims, and is the material consistent? Wouldn't want half the foam core be of varying levels of strength... I've thought a lot about building materials, and I'm pretty sure I want to go with Foam Core & Epoxy. Foam core because I want this boat to outlast me, and I don't want a soggy core. Epoxy because I think its harder to mess up then vinylester or polyester, and the elongation characteristics better match the glass.

    I think I'm in the unique situation of not being overly budget constrained, all things considered, nor time constrained. I think the biggest issue for me is going to be the drive to keep working on it day after day. My wife wants 2-3 kids in the next couple of years, so the boat would have to fit the whole family. I think a 40'er could probably do that, but not with any guests on board.
     
  12. comfisherman
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    comfisherman Senior Member

    Can't speak to epoxy as my work is all poly and vinylester. But my boats are heavy commercial tubs.

    Drive kills a lot of these projects. Especially if your popping out kids during the time frame. Abandoned boat projects on every coast of most developed countries from lack of drive as much as lack of money.

    It's worth thinking about, and having an honest conversation with the spouse.
     
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  13. guzzis3
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    guzzis3 Senior Member

    Ok another complicated reply. I'll try to get the quotes in thee right place.


    Woods :D

    You will see here over and over the advice:

    List your requirements. How many people ? What are you bringing onboard and what does each item weigh ? Weight is the limiting factor on multis, while space is the limit on monos. Once you have that list you can estimate your required payload and work back from that. I'll say it again the part of the hulls that is below water carries everything above water.

    Horstman's are different. His designes are "second generation" after Piver's. They have less dihedral so don't walk, but he also has a line of bridgedeck cabin cats. Also Horstman's tris have narrower beam than later designs. His website is a bit of a mess. If you go to the price page and click on the link you get a 1 page PDF of the boat. It has specs and useful pics.

    Go here:

    Ed Horstman Designs https://edhorstmanmultihulldesigns.com/price_order2.php

    And click on a design, you get this (for example)

    https://edhorstmanmultihulldesigns.com/pdf/Trimaran45_3view.pdf

    Then go to the models page for some other info, and the pics page. It's all over the place.

    I am not advocating a Horstman specifically, it's just he has a good range of boats in that size and it is indicative of weights accommodation etc in the size you are looking at. As I said previously I'd build one of the 40' Woods cats in open deck and then look at adding the bridgedeck cabin later if needed. The study plans are cheap enough and you can work out what you can fit in the space. With Woods you can always go cuddy cabin aswell which is an appealing option for lots of reasons.


    I would be surprised if any of RW's boats are that fat. Maybe some Horstmans are that fat, you'd have to ask. I'd think the tris are closer to 10:1 and cats from both slimmer than that. As I said before in all but the lightest winds the limiting factor should be you and your crew, not the boat.

    I was going to test it but got sick again (I've had a series of health problems before the strokes). Rob Denny tested and has just built a big cargo pro using it. I think there are threads here, he has a website (search harry proa). The stuff seems to work fine. Epoxy is twice the price of polyester and vinylester is half way. Each has problems but I prefer epoxy especially for infusion. Even if you say build a round bottom cat you can usually cast everything above the waterline in flat panel and get single curvature, and just cast the hull bottoms in a double curved mold. Like everything else provided you use common good options whatever choice you make will produce a good boat. It's only when people go off the beaten track that you really have to think hard about implications. You can build V bottoms, dory, multi chine all with flat panels, or go rounded to the waterline. It's only if you choose a design with a lot of double curves everywhere that the hull will get hard to build as a one off.

    How many guest rooms do you have in your house after you accommodate your kids ? Yep maybe friends will come out for a day, maybe even a weekend, but long term ? Every square foot on a boat costs many times what it does in a house. Build what you absolutely need, not what you want or you'll end up with a half finished nothing. Ed horstman has a tri about 32' or something that sleeps 1 double and 3 singles. You can get that is a 30ish foot cat even without a bridgedeck cabin. The real problem comes with the washing machine dryer diswasher double over with 6 burners... pool table... baseball diamond...

    You run out of payload before you run out of space. Add up the weight of everything you want to take and that will answer your question of how big you need.

    https://edhorstmanmultihulldesigns.com/pdf/Trimaran31_3view.pdf

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

    Sailing Catamarans - Rhea - performance cruiser with central cuddy http://sailingcatamarans.com/index.php/designs-2/5-catamarans-over-40ft/187-rhea

    Sailing Catamarans - Ondina - V hull open deck cruiser http://sailingcatamarans.com/index.php/designs-2/5-catamarans-over-40ft/186-ondina
     
  14. guzzis3
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    guzzis3 Senior Member

    Rereading above we may have a misunderstanding. When I was talking about width in hull I was talking about maximum beam, ie above the water. Torso and shoulder width. Beam in the materline will be narrower. I would think those Woods boats are maybe 4' on the waterline. Sorry if I was unclear.
     

  15. waterbear
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    waterbear Junior Member

    I think most people, myself included, don't understand what they are building when they embark on a boat building project. We are in love with the idea of the boat, but we haven't necessarily lived he reality. Yes, a 50ft cat has an impressive combination of speed and accommodation, but there are very serious disadvantages too. With this in mind, you might want to charter a couple of different size catamarans (say 40ft and 50ft) to better understand what you are signing up for.
     
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