Newbie needs help...

Discussion in 'Boat Design' started by FadeDude, Mar 19, 2011.

  1. FadeDude
    Joined: Mar 2011
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    Location: South-Africa

    FadeDude Junior Member

    Hey guys.. Ok I have gotten this crazy idea in my head to start building my own boat.. I ahve been "window shopping" for a while.... and have gone out with a freind a couple of times.... but I have decided I want my own boat.. literally.... there are certain design and functional changes I wish to include to suit me...

    I do have a couple of questions, as I am REALLY a newbie. I would aprpeciate if you guys can possibly share your views on my questions...

    1: How big a boat can I stick on a trailor. I don't wish to keep it permanently moored. But I want it bigger than the normal 17ft. I am currently working on a 7m design... 7m x 3m. Will this legally "fit" on a trailor, and can I go to 8m....

    2: Why do most motorized boats have such a HUGE nose that is not really used... I understand theres a cabin underneath... but it seems like the nose space is jsut simnply discarded up top...? Any particular reason?

    3: I am designing a double hall baby cat basically... but I want it motorized, not sail powered (for now). How do I determine boyancy? I need to know where the "flaot" line will be (float line - my own term I guesse) - water-line. I'm sure I cant be expecting to guesse it? and only realyl see whn its in teh water... this influences my design, especially at the back... how do I know what volume will be under the water, I guesse and guestimating the weight plays a role?

    4: How doe sone "build" such a double hull. I was obviously going the Fibreglass route, but can I make the itnernal frame from steel? Or is ti all jsut FB? I know a single hulel is probably just FB, but double hull? Support structures?

    Thats it fow now... trying to get my head around this so I can play with my design a bit mroe.. any thoughts?
     
  2. whitepointer23

    whitepointer23 Previous Member

    the only thought i have is get yourself a set of plans designed for first time builders. there are heaps of good designs available.
     
  3. FadeDude
    Joined: Mar 2011
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    FadeDude Junior Member

    Ok, thanks, fair enough.. I still need to satisfy my curiosity.... to kepe me dreaming my own design...
     
  4. whitepointer23

    whitepointer23 Previous Member

    there is nothing wrong with that at all, i just think if you bought some plans and built a boat you would gain so much knowledge that you could put into your own design. even building a dinghy or kayak will be a great learning experience.
     
  5. FadeDude
    Joined: Mar 2011
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    FadeDude Junior Member

    Thanks. You make sense... I will probably ahve to go that route intially, as I AM totally clueless. :) . My first step is researching in anyway, hence my questions.
     
  6. cthippo
    Joined: Sep 2010
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    cthippo Senior Member

    I'm not sure what the law in in South Africa, but in most places 8 meters is no problem. How big of a vehicle do you have to tow it and how far do you need to go? Take a look at what's on the road in your area to get an idea what can be done.

    I'm not sure what you mean by big noses, but IMHO the standard pleasure boat design is pretty ridiculous. The good news is that there are lots and lots of plans out there that look nothing like what you can buy at a dealer.

    What do you want the boat to do and what do you want to do on it? How far does it need to go and in what kinds of conditions? How many people does it need to carry and for how long? You've identified power propulsion and trailer-ability as design restrictions , are there others?

    Why are you looking at a cat design? What advantages do you see to it? The reason I ask is that cats + trailers = complexity. Can it be done? Sure, but the headaches involved go up exponentially.

    As for construction, look at CatBuilder's threads inn the boatbuilding section. They have a lot of pictures of the one he's working on and he's asking a lot of good questions you will probably encounter as well.
     
  7. FadeDude
    Joined: Mar 2011
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    FadeDude Junior Member

    Thanks cthippo.

    Have JEEP grand cherokee (all tiem 4 and low 4). Wont need to go to far... about 100KM at most... We live in teh Garden Route and tehre are a good number of lakes and estuaries that I want to make use of.

    Ye, big noses, as in, the whole front part of the boat is wasted (on top at least). I dont "get' the design, except that maybe it looks fast.. :) I ideally want to get hte MOST out of a boat, space wise, outdoor wise.

    Use of the boat? Just basically day cruises, maybe a sleepover in teh cabin. My family and I really love it outdoors, and we love the water. Kiddies are just over 2 years and just about 1 year. (2 boys), so in a while it will msot likely be the 4 of us mostly. Ideally I would like to carry at least 6.

    No real other restrictions..... except for I want to try to maxemise space... as to comnfortably spend a whole day, or even weekend, on the baot....

    Why cat? I ahve always been faciniated by them... the Knysna Quays has alot of those BIG cats, *super yachts*, and it has always facinaited me as a child.. I ahve this vision in my head of my craft when its done.... its a real good lookin vision...

    Thanks for the info man, getting even mroe excited....
     
  8. Squidly-Diddly
    Joined: Sep 2007
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    Squidly-Diddly Senior Member

    could you post pic of 'huge nose' on a boat?

    Is this what you mean?

    [​IMG]

    I think most if it is that being forward is such a harsh pounding ride. Only tough teenagers could handle it or think it was fun, and only for a few minutes, and they don't have the money for the boat, much less the fuel.
     
  9. Poida
    Joined: Apr 2006
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    Poida Senior Member

    Noses

    Probably a point on the front of a small boat helps the aerodynamics when towing it. Also it looks sleek, the resale value of a functional ugly boat will not be good. I know quite a few people who have built a boat they intended to keep then sold it.

    Build from boat plans for sure, and I would build in timber as it is more easily altered at a later stage to suit want you want.

    Check your laws on trailers as you will need to build one of those as well.

    Of course to get the largest trailable boat aluminium is a good choice.
     
  10. FadeDude
    Joined: Mar 2011
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    FadeDude Junior Member

    Thanks guys, yes that long nose is exactly what I was talking about.. the harsh ride makes sense now... good thing I am not aiming for a speedboat ride all of the time... :)

    regarding timber, yes I ams eeing mroe and mroe "construction pics", where guys are using wood.. I would have thought this practice stopepd with teh vikings? My thoughts are/were that wood would not ahve the durability of metals, or composites? And would skew and warp with humidity.... but ye, alot of guys are using wood. The right wood is probably the secret.....?
     
  11. cthippo
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    cthippo Senior Member

    OK, so powerboat with dimensions of around 3x8 meters, holds 4-6 people for day cruising on calm inland waters with the possibility of occasional overnight trips. That's a good start.

    Do you have expeirence in any particular construction method? If you're a welder or woodworker or have fiberglass expeirience then that may influence the best design for you. I'll start looking around for designs that might match what you have in mind.
     
  12. cthippo
    Joined: Sep 2010
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    cthippo Senior Member

    OK, here are some ideas...

    [​IMG]
    [​IMG]

    This is the Martha Green by Atkins 24' LOA, 8'4" beam and 2' 11" draft.

    http://atkinboatplans.com/


    [​IMG]

    This is the Redwing 26 from Chesapeake Marine Design.

    Length: 26'-0"
    Beam: 8'-6"
    Draft: 1'-6"
    Weight: 4800 lbs
    Power: 20-30 hp

    http://www.cmdboats.com/rw26.htm

    [​IMG]

    From Glen-L we have this 25' Coastal Cruiser

    Length overall 25'0" (*)
    Length waterline 23'0" (*)
    Beam 8'6"
    Draft (hull) 1'4"
    Displacement 5150 lbs.

    https://www.boatdesigns.com/25-Coastal-Cruiser-trailerable-motoryacht/products/802/

    [​IMG]
    [​IMG]

    Another tug yacht, this one from Devlin...

    Length: 26ft 4in (L.O.D.)
    24ft 8in (L.W.L.)

    Beam: 9ft 3in

    Draft: 3ft 6in

    Displacement: 8,000lbs

    http://store.devlinboat.com/kingfisher26.aspx


    These are just some possibilities. Give me an idea what kinds of designs turn your crank and I can find some more suggestions.
     
  13. FadeDude
    Joined: Mar 2011
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    FadeDude Junior Member

    thanks for all the help man! Appreciated. Let me give you a shot of what I am playing with design wise.... its not "architected" or anything, so don';t flame for hulle shape etc... I'm still just conceptualising...

    Regarding experience in building... well I am not an artisan by any means, but I can and have experience in woodworking, welding, fibreglass.. not specialising in anything really. BUt I grew up with a VERY DIY dad.... which forced my envolvement in these kind of things really...
     
  14. FadeDude
    Joined: Mar 2011
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    FadeDude Junior Member

    Current Concept

    This is what I have so far...
     

    Attached Files:


  15. cthippo
    Joined: Sep 2010
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    cthippo Senior Member

    I wish I had your rendering skills.

    What do you have in mind for the cabin?

    Where are you going to put the motor? You can put one in each hull, or use two outboards, or a single centrally mounted outboard. I would recommend against the first idea though.

    Here's something close if it helps you firm up the design in your head...

    [​IMG]

    This is an 8 meter cat from www.orca-marine.co.nz/catamarans.htm

    Available for immediate delivery for $285,000 or available as a hulls and deck kit.

    Based on their website I don't know if I would trust these guys, but they claim to offer plans very similar to what you've drawn...

    http://jetboatdesign.com/Order.php
     
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