Buccaneer 24 Builders Forum

Discussion in 'Multihulls' started by oldsailor7, Jul 22, 2009.

  1. Saylaman
    Joined: Dec 2007
    Posts: 35
    Likes: 3, Points: 0, Legacy Rep: 43
    Location: Sydney, Oz

    Saylaman Junior Member

    Thanks very much for the information. I appreciate your help.
     
  2. robjgould
    Joined: May 2010
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: UNITED KINGDOM

    robjgould Junior Member

    Buccaneer 24 potential build project

    Hi folks, I'm interested in building a Buccaneer 24 here in the UK and thought I'd post a reply here to introduce myself and the potential project.

    I've researched what's available plans wise and the Buccaneer is a clear winner for a number of reasons. After many years of sailing, building and owning boats I've come to appreciate that simplicity very much rules in my book. Most modern designs are way too busy, expensive, and quite frankly ugly! I know these may be extreme views but if I'm going to invest a large amount of time, effort and money into a project this size, then any potential design must satisfy my needs totally.

    I realise that the Buccaneer is an old design, based upon hydrodynamic theories and construction methods of a byegone era, however the longevity of designs such as this proves that they work. The main problem I have is that I've not sailed on a Buccaneer 24 and hence can only gauge her performance from authentic accounts. I have a number of magazine reports etc. that all praise the attributes of this boat both in terms of her and design and also her construction. Although she clearly isn't in line with modern design and construction theories, my seriously considered response is 'so what?'

    Anyway I'll try to purchase the plans in due course and then do a project appraisal to determine expected costs etc. Nothing new there to anyone using this forum.

    Cheers for now.

    Rob
     
  3. gypsy28
    Joined: Mar 2010
    Posts: 218
    Likes: 26, Points: 28, Legacy Rep: 120
    Location: NSW Australia

    gypsy28 Senior Member

    Oldsailor7, I'm interested in purchasing a set of Buccaneer 24 plans, I cant figure out how to PM you though :confused:
    Thanks,
    Dave
     
  4. oldsailor7
    Joined: May 2008
    Posts: 2,097
    Likes: 41, Points: 48, Legacy Rep: 436
    Location: Sydney Australia

    oldsailor7 Senior Member

    gypsy28

    Just click on my pseudonym (oldsailor7).
    Scroll to "Send oldsailor7 a PM" and send me a message. :D
     
  5. gypsy28
    Joined: Mar 2010
    Posts: 218
    Likes: 26, Points: 28, Legacy Rep: 120
    Location: NSW Australia

    gypsy28 Senior Member

    Hello gentlemen,
    I have received my Bucc 24 plans from Oldsailor7 and will begin making sawdust in the coming days.
    My question is regarding the rudder, transon hung or underslung? any opinions
    Dave
     
  6. oldsailor7
    Joined: May 2008
    Posts: 2,097
    Likes: 41, Points: 48, Legacy Rep: 436
    Location: Sydney Australia

    oldsailor7 Senior Member

    It's just MHO but in thr case of the B24--unless you are going to engage in serious racing, you are better off all round with the transome hung rudder. Apart from anything else is is so convenient to pivot it up when sailing up a beach, or when on a mooring. (and not forgetting-- when you hit a Turtle) :D
     
  7. rcracing2
    Joined: Aug 2010
    Posts: 32
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Burdekin, Nth Qld

    rcracing2 Junior Member

    putting my Buc 24 back together again

    Hi everyone. Ive had my Buc 24 since 2005 but she has only been on the water for about 18 months of that time. For the last 3 years 'Fruit Bat' has been stored out of the weather on my in laws cane farm. Im finally now in a position to put her back together. Before i took her to the farm, she was stripped of all fittings and i had begun to sand her for a repaint. I also modified the front 'berth' by adding an anchor well and some flooring to make it more comfortable. I was having to lug the anchor from the stern locker forward whenever i wanted to use it. Pretty annoying when your trying to enter lake macquarie from the sea with a run out tide and as your going under the bridge(which has to be lifted) your motor dies!
    Anyway back on topic. My biggest problem is that Fruit Bat has fixed, timber hollow box beams and i had to cut them at both the main hull and also the amas to enable her to be transported the 2000km's to her new home. I have some half brained ideas about how to go about joining her back together but no experience to give me any confidence to do so. The biggest issue is that from the cuts i had to make there is 150mm of hollow box section before there is plywood stops(i'll post some pics i took on the weekend hopefully). i had thought of using either a hardwood or alloy box section as a sleeve in the hollow and then glassing the join and through bolting in several places. Im just concerned that a 150mm join wont be sufficient for the loads it will carry. Im really looking for ideas to join it all again,

    Thanks in advance,

    rcracing2
     
  8. Samnz
    Joined: Nov 2008
    Posts: 235
    Likes: 4, Points: 0, Legacy Rep: 47
    Location: Auckland

    Samnz Senior Member

    I wouldnt be too stressed about the repair, it only needs to be as strong as the beam was, and if you scarfed in a piece of timber 150mm would be enough as long as it wasnt more than 15mm thick, which surely it isnt? you can also put a "butt block" inside (on each edge) to reinforce the join if your worried, then a bit of glass and itl be as good as new.
    can you describe the construction of the box in more detail?
     
  9. rcracing2
    Joined: Aug 2010
    Posts: 32
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Burdekin, Nth Qld

    rcracing2 Junior Member

    Thanks Samnz. The box is 125mm across, 123ish in height. The outer skin of the box section is 10-12mm plywood. On the sides in the 'box' are 3 timbers squares each side which is all compressed together. This leaves a hollow section in the middle which is 40mm wide, 100mm high.
     
  10. oldsailor7
    Joined: May 2008
    Posts: 2,097
    Likes: 41, Points: 48, Legacy Rep: 436
    Location: Sydney Australia

    oldsailor7 Senior Member

    A picture or a dimensioned drawing would be a big help to visualise the box beam structure.
    The crossbeams on a multihull are too serious a structure to be altered BG & BG ---or by TLAR.
    The upper and lower members (booms),take all the tension and compressive loads, and the sides (webs) take shear and torsion loads.
    The sides in this case can simply be joined by butt plates of the same thickness and material. The upper and lower booms must be doubled with similar pieces at least 10 times as long as their thickness --- as Samnz has pointed out.
    The ends of these pieces should also be chamfered to a taper to prevent a stress concentration at their ends.
    All joins must be made with marine epoxy and all bare surfaces must be covered with at least two coats of epoxy to prevent water absorbtion.
    Hope this helps. OS7.
     
  11. rcracing2
    Joined: Aug 2010
    Posts: 32
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Burdekin, Nth Qld

    rcracing2 Junior Member

    Thanks OS7. Once i get to 5 messages i'll PM you and send you the pictures i took. You probably know the boat. Its name is Fruit Bat and i bought her from Pittwater when i was working at Hood sails.
     
  12. robjgould
    Joined: May 2010
    Posts: 7
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: UNITED KINGDOM

    robjgould Junior Member

    Hi, the problem of joining the beam sections into a whole unit again is not an easy one to solve......

    Crowthers original beam and water stay method is a light and relatively inexpensive structure, which he very efficiently tied into the main hull. The main loads on his beams are compression loads as the water stays effectively hold the beam in column and take care of bending. The box beam structure used in Fruit Bat is an entirely different engineering approach and creates different loading paths to the original method. (I'm assuming that water stays are NOT fitted as they weren't mentioned in your post?) Your beams are now heavily loaded in bending, with concentrations at the very point you've cut them. Given that the tri was successfully used prior to her surgery, the structure obviously worked as intended. However your concern regarding rejoining the cut parts is justified! A metal beam structure would have been easier in this respect due to the mechanical properties involved. A built up wood and plywood box beam is much more difficult to design and build due to the wildly varying and non linear structural properties of the woods utilised, and also the adhesives and fasteners.

    The loadings on a trimarans beams and attachments are difficult to calculate, and many broad assumptions are made so that common engineering formulae can be used to design them. Generous safety factors are added to counter any deficiency in these assumptions etc. The beam to main hull loadings are generally considered to be some of the highest due to the geometry of this structure. Given that the box beams were designed and installed as a cohesive structure, cutting them as you were forced to do has effectively rendered them 'under designed.'

    Rejoining them using either internal or external sleeves (or combination of the two) will create localised stressed areas that may fail in due course. A great deal depends on the exact structure of the box section beams and whether there is sufficient structure to accept the additional sleeve loads (eating into their respective safety factors)? Generally an inadequately sleeved connection fails either at the sleeve itself, or just beyond the sleeve when the joint is put under load.

    The alternative method is to scarf new pieces in place per the existing scantlings. However, this still breaches one of the biggest principles in wood structures in that you will have a scarf joint on all four faces directly opposite each other. All scarf joints in beams and mast etc. should never be located opposite each other! You won't find any drawings (of repute) telling you otherwise.

    The beam to float connection is less of an issue as they are dealing with different loads and load paths to the main hull connections. Here adding sleeves or scarfing 'may' work if enough care is taken to fabricate and assemble properly.

    Without a detailed analysis of the beams and there connections, it's extremely difficult to design a correctly engineered solution. A structural engineer, or experienced multihull designer would be needed to design a suitable jointing method, if indeed one does exist. To attempt a 'seat of the pants' jointing method may end up with the trimaran disastrously coming apart when under sail.

    The correct solution is to replace the beams with new ones to the same specification and install them in the original manner. This is the only 'safe' way of rejoining the hull, beams and floats, and will remove the ever present headache of whether the joints will fail! Alternatively could they be rejoined using the alloy tube and water stays as designed by Crowther? This would allow the tri to de disassembled any time in the future without any problem. This may not be a consideration to you at the moment, but if Fruit Bat was ever sold on (AHHHHH!) then this demountability would be an advantage.

    Multihull design is problematic and many structural failures have been documented, even very famous and well funded projects. If the experts can so dramatically make mistakes, what chance the amateur? Whatever solution you work out I urge you to have your idea scrutinised by an industry expert. Multihull structures should be built as engineered and designed, with any alterations being approved by the designer (sadly not possible in this case). The question of insurance may also require that a professional approve your method. The worst scenario being if an inadequate repair were to fail and cause harm to third parties, thus nullifying your insurance.

    Sorry to sound so pessimistic but I just wanted to make you aware of the extent of the problem you're facing.
     
  13. rcracing2
    Joined: Aug 2010
    Posts: 32
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Burdekin, Nth Qld

    rcracing2 Junior Member

    Thanks for the info robjgould. The boat does still have waterstays fitted and i should've mentioned that. Part of the reason it has taken me so long to get Fruit Bat on the water is the beams. As soon as i cut the beams and looked inside i knew i has issues because of the plywood stops inside. I had thought of going back to original beams but again, i dont know how to go about the whole process. I'll get some pics up and you guys might be able to give me more info,

    Cheers,

    Robert
     
  14. rcracing2
    Joined: Aug 2010
    Posts: 32
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Burdekin, Nth Qld

    rcracing2 Junior Member

    [​IMG]

    This is a drawing of the beam structure. Around the outside is 12mm plywood with the 2 rows of timber either side on the inside. The hollow that is remaining in the middle is 40mm x 100mm.
     

  15. rcracing2
    Joined: Aug 2010
    Posts: 32
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Burdekin, Nth Qld

    rcracing2 Junior Member

Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.