Substituting for Mahogany

Discussion in 'Materials' started by APA-168, Aug 1, 2008.

  1. APA-168
    Joined: Feb 2008
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    Location: Barto, Washington township, Berks County, PA, USA,

    APA-168 student amateur designer

    I was reading up on substitutes for Mahogany, and it was implied somewhere that Paulownia could be substituted. Any thoughts on this? Good idea or no?

    If no, then what could I safely substitute for Mahogany that will be fairly easy to get and cheaper, and preferably won't promote tropical deforestation.

    The boat I'm looking to build is a 12' sloop. The wood is needed largely for flooring etc. with only a couple pieces needed for structural applications. Main hull material is plywood.

    Thanks so much in advance.
     
  2. kengrome
    Joined: Jul 2006
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    kengrome Senior Member

    You know ... in places where Mahogany grows naturally the local boat builders avoid using it in their boats. They do not think it is a very good boat building material, and neither do I. The fact is, there are better tropical wood species available for building boats ...

    Mahogany is pretty, I'll give it that. It is also relatively stiff and strong -- until it starts getting wet -- then it begins to disintegrate into short disconnected pulp-like fibers that are worthless in terms of strength.

    For structural applications I suggest using Meranti or Douglas Fir. You can use anything you like for your floors since they are easy to replace. If you're worried about rot, treat each piece with Copper Naphthenate after you've cut and shaped it but before you install it.

    By the way, Paulownia is probably good for strip planking that's sheathed with glass and epoxy inside and out, but it's not that strong so I would use something else for structural applications if I were you.
     
  3. alan white
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    alan white Senior Member

    Things get dropped on floors (soles). Paint the sole boards and you'll be better off. Try a light wood like fir or pine. Because a sole's painted, a softer wood (which dents more easily) can have dents filled upon repainting, always looking good. Softer woods like those mentioned exert far less pull on fasteners when assembled as sole sections are. Harder woods such as oak or mahogany will pull too much, cupping in the direct sunlight to some degree.
    Even cedar is fine for soles.
    I can remeber my father's new house was clapboarded in luan mahogany (only a moderately dense cedar) because of a red cedar shortage at the time, but the luan was dense enough to pull the nails completely out from moisture cycling. If it had been white or red cedar, the fasteners would never have been moved.
    I'm not saying this will always happen---- but the softer woods are more forgiving of moisture cycling (a poorly kept paint job) compared to hardwoods, which are better used in curves or hidden in the interior if not kept up rigorously.

    Alan
     
  4. Butch .H
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    Butch .H Senior Member

    For structural applications I suggest using Meranti or Douglas Fir.Kenneth would that also refer to laminated ribs?(sistering up the ribs in my boat)
     
  5. kengrome
    Joined: Jul 2006
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    Location: Gulf Coast USA

    kengrome Senior Member

    Hi Butch,

    Yes, both Meranti and Douglas Fir are fine for ribs -- but so is oak and many other types of timber. It may be best to use the same material for the sister material as the original ribs if you can, assuming the original specie was a good one for ribs to begin with of course. Oak is very popular for use as ribs in the USA, but we use tropical species over here ...

    There's a really hard, strong, basically rot-proof wood in the Philippines called "Tugas" that is extremely popular with the local boat builders. It is relatively expensive here, and I doubt it is available in the USA because the Philippines imposes a ban on exporting some of these species as raw lumber.

    I can use it to build my boats and then export the boats however, because "manufactured products" using Tugas and other great boat building species are actually approved for export, it's just the raw material that's not exportable ... :)
     
  6. Butch .H
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    Butch .H Senior Member

    Cool thanks Kenneth
    Regards
    Butch
     

  7. Aethelwulffe
    Joined: Jun 2008
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    Location: Tampa Bay

    Aethelwulffe Junior Member

    What is this mysterious mahogany species that "disconnects into short fibers" when in the prescence of water???
    I am currently working on a boat built of a combination of African Mahogany, Obeche, Honduran Mahogany, and a wood known to me only as St. Andrew. The boat was built in 1958. All the Deadwoods ae in fantastic shape, and they are certainly made of a dense African Mahogany. The frames and floors are made of honduran Mahogany, as are all the original planks. The forwardmost planks of almost every course of planking are now Obeche, as the stem was replaced in 1971 to give her a plumber clipper bow and to add a sprit. The stem appears to be live oak. We are re-caulking her. I have noticed no "disentigration into short fibers". neither is the venerable old Matthews 53 we are re-canvassing the decks of, built of Honduran. Nor is the Trumpy. The Chris-craft is disentigrating, but that is because it is a terribly built 35 y/o clamp-seam wreck made of paper-thin luan planks ("phillipine mahogany" as some people call it). I have seen a 400 year old Koa (Hawaiian Mahogany) sufboard that showed no sign of "disentigration. I bet that over the years it has been in the prescence of water.
    Florida mahogany is not a widespread species. Until Cuban mahogany was logged to extinction, most all the little boats built on the beaches of that island were made of Cuban Mahogany. My first boat, salvaged from the mangroves after some refugees putted there way to the Florida Keys. My grandfather and I floated it out after he dropped the Cubanos off at the INS in his truck. I was 16. He declared the hull to be made of Cuban Mahogany (my Grandpa's word and experience in these matters was beyond reproach). Being that the species had been logged off about 100 years before that time, that sort of narrows down the possible age of that tennon-fastened hull. After I went into the Navy and my grandpa died, the hull went into Mallory Square in downtown Key West. Guys beat her up with hammers and saws. They sand blasted her and painted a stupid new name on her with cheap paint that aged quickly to make her "look antique" and turned her into a planter, where she sits to this very day. She has not yet disentigrated into short fibers.
    Ask my friend Alexandro de Silva-Luna (origianly from Sao Paulo Brazil) whom has a shop in Sanford (Florida) why they don't use much mahogany in Brazil. Simple. The stuff can be very hard on saws and planers compared to many softwoods _when harvested green_. It is also very hard to cure in high humidity. They build many boats with green wood...get it? He will go on and on about how when he was apprenticed, there were only two power tools in the shop. Now he has no problem working with mahogany...but preferes African to South american species as I do. Both of us actually would rather work with domestic woods rather than imported.

    Mahogany is a name that comprises many species that are not mahoganies. There are some mahoganies that are not called mahogany. There are many substitutes for mahoganies if you want to sort of match grain before you smear some hideous red stain all over it. There are few woods that allow you to fasten and shape like you can with mahogany. White oak is close, but doesn't often have as good of grain when flitch-sawn.
    A good "substitute" might be Spanish Cedar, but it is nasty stuff to work with (you need a respirator...it is even worse than Myrtani). If you want to build a plywood sloop, may I recommend that you go order up a couple of chunks of Americano White oak? Live oak would be nice, but you can dependably get white oak, and it is a fine floor, frame, and deadwood material. It doesn't take self-tapping decking screws anywhere near as nice as African Mahogany, but if you don't mind piloting, you will do well with it. For the planking, 1088 certified Marine Okume manufactured by Endesa is from well managed areas. If you want all-domestic, your common local variety of marine fir is a fine wood. It just masses a lot more than the Okume, and isn't quite as strong (it is very good stuff though), isn't as pretty, doesn't take paint as well (has to be faired to hide large grain, unlike the cabinet quality outer veneer Okume), but it fastens well and lasts a long time. White pine, cedar (white cedar if you can get it) more okume, or lots of other species work great for a sole, if you are going to have a sole in your little boat.

    More friendly advice: Don't use red oak for ANYTHING...except firewood
     
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