Planking and epoxy

Discussion in 'Wooden Boat Building and Restoration' started by F.H.B., Dec 30, 2009.

  1. F.H.B.
    Joined: Dec 2009
    Posts: 27
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Utah for now

    F.H.B. Junior Member


    Could a dory handle that sort of superstructure, Par? She wants what seems to be about 75' of boat in less than 50' of length capable of sailing. I suppose I could steer her to catamarans, but she likes a mono hull...

    Thanks also to all for the pointers to plans. Can anyone think of a design where the coach house is over full-height living space and it still sails?
     
  2. F.H.B.
    Joined: Dec 2009
    Posts: 27
    Likes: 0, Points: 0, Legacy Rep: 10
    Location: Utah for now

    F.H.B. Junior Member

    Thankfully, we got off topic and on to what we are really trying to do. I will make a new thread with a better topic title.
     
  3. sabahcat
    Joined: Dec 2008
    Posts: 792
    Likes: 28, Points: 0, Legacy Rep: 273
    Location: australia

    sabahcat Senior Member

    LOL,
    doesn't everyone


    Yep
     
  4. Boston

    Boston Previous Member

    so Par a question
    you seem to put a lot of faith in epoxy
    so why if your slathering epoxy all over a cold molded hull do you so consistently speak against tulip wood. yes its not very rot resistive but everything else about it makes it perfect for cold molding not the least of which is its <$1 per foot price. Its clear straight grained material comes in huge lengths, the charictoristic differences between sap wood and heartwood vary only slightly and its got consistent strength, its also light and takes chemical treatments like glue, stain and preservatives extremely well. Slathered with epoxy would it not be protected from moisture and therefor not prone to rot or if so could it not be treated with a epoxy compatible preservative.

    Ive built lots of **** out of poplar and I love the stuff, just not a boat yet. So sock it to me, whats the deal that between preservative and epoxy you still seem to consistently speak ill of this type of wood.

    FHB
    first thing you are going to want to do is realize everything about a boat is a compromise. I been working up to a retirement build for a while now and I still got a long way to go before I can think that Ive pinned down what I want to build. Your girl needs to either back off and let you do your diligence work or do her own. Best thing to do is hang out and read for a few years, speacially the threads that focus on people who are trying to do exactly what you are doing but screw it up. There is some great humor in them but the underlying tradgedy is that someone had a dream and could have been humble enough to realize that for as smart as they think they are, they need help to make it come true, when it comes to a yacht, a lot more help than you may realize at this point in your research. Keep asking questions but do not fossilize yourself into one method or design. The hull is only a small part of the build.

    best of luck and if its really what you want then study first
    build last
    and survive for a long time

    luck favors the prepared

    B
     
  5. apex1

    apex1 Guest

    FHB

    there are (at least) three very dangerous faults in your assumptions.

    First, you believe you know your requirements! That is quite obviously not the case.
    Second, you believe that designing your own boat can save you money. The opposite is true.
    Third, you believe a homebuilt will be cheaper than buying a boat. In more than 90% of the adventures that is´nt the case.

    Build a dhingi to a proven plan, as mentioned above. You´ll get a idea what you are in for.
    Narrow down your requirements (leave the dreams out, they will take place later again).

    Buy a proven plan and build it EXACTLY to the scantlings, when you still are for the homebuild way.
    Pay a NA to customize the purchased plan if need be.

    Or do as advised, buy second hand, save money, stress, a divorce, and time, and enjoy sailing now, not in 8 years!

    Look here to get a clue what requirement can be:
    http://www.boatdesign.net/forums/boat-design/design-spiral-where-start-building-boat-28580.html

    Regards
    Richard
     
  6. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Tulipwood (common poplar) has a nasty habit of breaking across the grain with little force. Now picture a bunch of strips, with the their grain running pretty much along the fore and aft load paths. The natural strains of the boat will tend to break this species across the grain, which places huge structural considerations on adjacent strips. I can see one strip snapping, then it's use as a load bearer is over, so the strips on either side pickup the load and they snap, etc., etc., etc. Epoxy isn't going to fix this. Epoxy and fabric will, but now you're defeating the need for the wood in the first place. Basically this wood is great under paint and most importantly in static load situations. Cabinet frames, furniture, etc. it's wonderful stuff, but not in dynamically loaded structural elements.

    I should qualify this with Liriodendron tulipifera being the wood we're talking about. An my data on the species:

    Hardness (side grain) - very soft
    Bending strength (MOR) - low
    Shearing strength (parallel to grain) - very low
    Work to Maximum Load - very low
    Max. crushing strength - low
    Modulus of Elasticity (stiffness) - low
    Max. crushing strength - medium
    Modulus of Elasticity (stiffness) - very low
    Shrinkage, Tangential- moderate
    Shrinkage, Radial - moderate
    Bending strength (MOR) - very low
    Toughness-Hammer drop (Impact Strength) - very low

    Unless we're talking about Dalbergia frutescens, which is a different animal all together and not suitable at all for much more then decorative trim pieces
     
  7. Boston

    Boston Previous Member

    interesting
    we must be looking at different sources cause the US Navy Wood Manuel numbers on it place it right about average in most categories and consistently better than Western Red Cedar almost across the board. A lot better actually a wood typically used for planking applications

    I know you have mentioned that my sources are old but having worked a fare bit with the stuff, I know it works going through the machinery better than red ceder which usually means stronger although some woods are so hard they get to the point where they shatter, poplar tends to work well and has reasonable machining characteristics although it does get fuzzy if the blades are dull

    whats your source on the previous
    Ild love to do a little research on this

    another question I might have is when was the last time you used poplar and for what
    I built a set of windows out of it a while back because of its habit of not warping over time
    stuff tends to stay where you put it is what Ive noticed
    a couple of them were fairly large windows as well
    no call back and the customer was happy with them
    worked like a charm
    I think I put metal cladding on them, cant remember

    all that being said I am always open to new input so what was that source you quoted from

    cheers and have a great new years
    B
     
  8. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Again, it's great on windows or as barn siding, but not in a dynamic loading situation.

    The US Navy's wood information has to be a half a century old man, don't trust it.

    Poplar used to be fairly good stuff when there was a distinction between yellow and white, but now it's all basically the same and considered of lesser quality (it's all white now).

    Most of my information comes from the latest volume from the USDA, which covers the majority of domestic and imported woods in the USA. I also have other sources. A commonly used one by others here is Wood Explorer.
     
  9. apex1

    apex1 Guest

  10. Steve W
    Joined: Jul 2004
    Posts: 1,844
    Likes: 73, Points: 48, Legacy Rep: 608
    Location: Duluth, Minnesota

    Steve W Senior Member

    Im curious about the poplar also but i have very little experience with it.Back in the 90s when we were manufacturing snowboards the most common woods used for cores were Doug Fir,Aspen and yellow poplar. The choice was largely regional, based on where the manufacturer was located,we used aspen which naturally i felt was the best choice. I take it from reading here that yellow poplar is not tulipwood, is it a suitable wood for boatbuilding?
    Steve.
     
  11. Boston

    Boston Previous Member

    I always get the "Tulip" variety which is kinda greenish yellow. the white stuff is more closely related with Aspen and is crap Ill grant that one in an instant. Those large opperable windows are definetly under a dynamic load, speacially considering that they are casements and the glass I used was 1 3/8 heat mirror, very heavy stuff.
    I'll go check out those references and see what they have to say as well as maybe conduct a few tests myself to see how the stuff I get actually stacks up to the tests

    cheers
    and thanks for the info
    B

    on a cursory glance ( am heading out to a party ) I can see that the numbers posted in the Numerical data section of the wood explorer when compared to the numbers I have on red ceder place poplar superior to ceder in nearly all categories
    I really have to run but I will post a comparison, not necessarily for you guys but because writing it is helpful to my research on the subject
    Im not as much out to change any minds as I am into learning whats what

    I was curious if the verbal description of its characteristics was comparing apples to apples when considering typical woods used for planking
    seems when you compare the actual numbers things look up considerably for Tulip wood
    the receapt I have for my last purchase specifically says Tulipfera

    in log form I can get the stuff for about 15C a foot
    c4s
    nothing to sneeze at
    as long as it is comparable to other woods typically used for the same purpose

    just out of curiosity whats yellow pine going for these days a board foot ?
    anyone

    dam
    Im going to be late
    ok
    later folks
    happy new year
    B
     
  12. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    A window, even with some fancy hardware attached to it is a static load, not dynamic. Most structural lumber in boats will be asked to accept cyclic loading, particularly planking. This is far from the static environment of a window in a sash, even if occasionally it's opened or cantilevered on hardware.

    Tulipwood, Tulip poplar, Tuliptree, Saddle tree, Awhitewood, Canadian whitewood, Canary whitewood, Whitewood, Yellow-wood, Canoe wood, Green cypress, Popple, Poplar, Blue poplar, Hickory poplar, Virginian poplar, White poplar and Yellow poplar are common names. There are a few others, but less commonly used.

    Again, it was once a prized small boat planking material, when there was a clear distinction between the yellows and whites. The yellows where much favored, by boatbuilder and barn builder alike, for it's durability and rot resistance. Barns all over the midwest have 50 year old yellow poplar on the them as siding. This wood doesn't exist any more, it all got chopped down and replaced with farm raised or inferior hybrid poplars. This transition from the second growth stuff to the present day is about 50 years long, starting in the 60's. Ask any old time midwest barn builder or saw mill operator about the "real yellow poplar" they used in his youth and he'll smile and tell you the same thing, about the wonderful qualities of that old growth and first cut poplar.
     
  13. Oyster
    Joined: Feb 2006
    Posts: 269
    Likes: 9, Points: 0, Legacy Rep: 104
    Location: eastern United States

    Oyster Senior Member

    Happy New year and this thread was worth the read for the start of the new year. Strip plank and epoxy is done all the time in 50 footers. Designing a 50 footer using a computer program and a book is not a good mix for sure without some previous knowledge of what it takes to float a boat. Of course if you have the wallet big enough to do this project, divert some of it to a designer that you can give your perimeters even allowing your wife to pass along some imput, and you stand a good chance of surviving the savage sea. 2.25 thick planks,,,hah PT boats will need bigger bullets.:D
     

    Attached Files:

  14. PAR
    Joined: Nov 2003
    Posts: 19,126
    Likes: 498, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Glad to please Mike, good to see your post . . .
     

  15. Oyster
    Joined: Feb 2006
    Posts: 269
    Likes: 9, Points: 0, Legacy Rep: 104
    Location: eastern United States

    Oyster Senior Member

    Few people would even attempt to build an auto from scratch and will take at least a frame from a known vehicle and convert that to their own liking. Yet many will jump off the cliff in an attempt to design and build investing in this case several hundred of thousands of bucks on something after reading a book? Maybe the next person will attempt an airplane. YOU never know.:p I can see a rowing skiff or a pond boat. Of course this seems to be latest fad. Now where is that thread with the 40 foot boat for free that is all gutted out and planks opened all up thats been sitting around on the hard since I happen to have a couple tubes of 5200 and a gallon or two of kilz laying around. I bet by the end of the month I can have it ready for a late carribean cruise and fishing trip too.:p
     
Loading...
Similar Threads
  1. RMMager
    Replies:
    14
    Views:
    5,011
  2. Rush Wingate
    Replies:
    9
    Views:
    1,149
  3. sdowney717
    Replies:
    4
    Views:
    1,206
  4. timewaster
    Replies:
    7
    Views:
    4,593
  5. rwatson
    Replies:
    0
    Views:
    2,263
  6. Windship277
    Replies:
    112
    Views:
    15,277
  7. shipwright
    Replies:
    13
    Views:
    3,476
  8. Corley
    Replies:
    7
    Views:
    2,324
  9. goingjag
    Replies:
    7
    Views:
    2,509
  10. advobwhite
    Replies:
    18
    Views:
    5,362
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.