Sapelle vs. African Mahogany

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bobinpowayca
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Location: Poway, CA

Sapelle vs. African Mahogany

Post by bobinpowayca » Wed Jan 23, 2013 4:29 pm

Hi, (I also posted this in the wood section) - I'm ready to buy frame material (deciding on Malahini or Geronimo) so went to the hardwood source here (Frost Lumber in San Diego) - they have available Sapelle in finished 4/4 (25/32 net) and African Mahogany in both 5/4 and 4/4. Both looked nice although the Sapelle had generally much straighter grain and fewer bows.
First thing I noticed is the Sapelle was VERY heavy (like white oak or soaking wet fir) compared to the African Mahogany, which seemed very light weight. The advantage I see for the african mahogany then, is that I can plane the 5/4 down to a net full inch, and still be much less weight than the sapelle. I'm a novice but to me it seems better to have a full inch in frame thickness as far as a better landing for the planking and truer fairing.
The disadvantage (?) is that the african mahogany is way down the hardness list (845 psi), right down there with doug fir, whereas the sapelle is midrange hardness (1500).
Any thoughts on african mahogany or sapelle would be greatly appreciated. I don't think they have the dark phillipine mahogany at this store. Thanks a lot, Bob
Bob
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Built the Glen-L 17 (1988), Geronimo (2018)
PBR support (1968)

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DrBryanJ
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Re: Sapelle vs. African Mahogany

Post by DrBryanJ » Thu Jan 24, 2013 3:56 am

I bought 4/4 african mahogany for my frames. Planed on both sides came out to about 7/8 thickness. It is working nicely. Needed 13 ft or longer pieces for keel and stringers and african mahogany was not available so switched to sapelle. It is much heavier and a little harder to cut. Both plan nicely with my hand plane. Haven't tried to bend chines or shears yet. I think both would work fine, but I would use the 4/4 african mahogany due to the weight.

Bryan
Bryan

Building a malahini "Mona Lisa"

My wife said "If I build a boat, she's getting a divorce."
We're still happily married, but now she just wants "the dam boat out of the garage."

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Iggy
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Re: Sapelle vs. African Mahogany

Post by Iggy » Thu Jan 24, 2013 8:57 am

I've only worked with Sapelle. I had it planed down to both 7/8" and 13/16" thickness, and it is plenty strong at that thickness. You don't need the full 1", you really don't. The BOM is 1" nominal, which means anything from 3/4" up to 1" is perfectly suitable. If you scale the material on the Malahini patterns, its showing 7/8" thick battens, chines, frames, etc.

Khaya (African I believe) was a bit more expensive, and the quartersawn wasn't as straight grained, so I chose Sapelle instead.

Sapelle was lighter that white oak and I liked the look better even if it was slightly more expensive.
Ian (aka Iggy)
My Malahini Build

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kens
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Re: Sapelle vs. African Mahogany

Post by kens » Thu Jan 24, 2013 6:58 pm

I did some testing with all the various woods I had on hand, and found that the weight of the wood had a pretty much straight answer to its strength.
You had mentioned that mahog was lighter than Sapele. I found my Sapele samples a lot stronger than my Mahog samples, and saplele was heavier too.
I did notice that all the strongest woods were also the heaviest.
I am not an engineer, nor did I write down specific numbers, but I hope you get the idea.

Mahogany is considered the 'standard' wood to use, and I found it only 'average' for strength. There are many woods stronger than mahog; any oak, yellow pine, ash, sapele, hickory, are all stronger. Some of my Spanish Cedar was stronger than mahog.

Mahogany is considered good because:
it is slow to rot, holds screws well, glues well, swells little when wet, doesnt dull tools, relatively light, looks good, and believe it or not it is only 'averadge' in strength. It is all the 'other' properties that make Mahogany superior.
Sapele is my favorite because I can get it cheaper than Mahog, the difference in weight isnt much, and saplele looks better than mahog. Sapele is a cousin to mahog and is a very fine wood.
Oak is over rated, everything about it takes extra time; then it warps, splits or checks !!! :roll:

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