Wood Materials Question

[projectfiji]

Good Morning Cruisers Forum,
I spent my weekend reading Buehlers "Backyard Boatbuilding" and Gerrs "Elements of Strength" over the weekend. I'll probably post a million followup questions in regards to the two books, so bare with me.

My question this morning comes in the form of using Cedar planking as a hull material. I have available to me 60 acres of White Cedar, free for cutting (some strings attached, I'll post about that later). Gerr says that White Cedar makes an acceptable planking material on boats up to 45'. I assume this is due to structure issues dealing with weight loads and displacement, but he really doesn't touch on the specifics. I understand it's a slightly lighter wood, is that the reason?

[GordMay]

As noted on page 14 of “Guidance on Inspection, Repair, and Maintenance of Wooden Hulls” (NVIC 7-95) < http://www.uscg.mil/hq/cg5/NVIC/pdf/1995/n7-95.pdf >

Yes - Cedar(s) are not commonly used where strength is a prime consideration.

[SkiprJohn]

Aloha Project,
My friend used douglas fir 2x4s and 2x6s from the local lumber yard on his Buehler "Juno" design. In tropical islands you must haulout annually to keep ahead of the shipworms. He didn't and he had to replace some of the underwater portions of his hull. I helped him haul and when the crane lifted the boat out of the water you could put your finger through the planking in a couple of areas near the waterline but below it. After relaunching with copper sheathing on the bottom he found some dry rot in the cabin and at age 80 could not keep up with the maintenance. He gave away his boat, the new owners never did any maintenance and now it rests on the bottom in Radio Bay. My friend is heartbroken about it and would have preferred to sink it himself rather than see it slowly go downhill.
Just an experience about wood hulls in tropical climates. You really need to find out where you intend to sail if there are haulout facilities if your choice of building material is wood. The other consideration is that many fiberglass hulls are really inexpensive in this economy. If you are intent on building, I'd consider rebuilding on a fiberglass hull. You could use all the rest of Buehler's ideas for completion.
Kind regards,
JohnL

I have used Port Orford Cedar for all of the framing and hatches topsides on the trimaran. So far no issues. A friend of mine had a Tahiti Ketch that was cedar planked. He replace several planks one year, and the next year, when he hauled out, those same planks were completely rotted. He is very thorough, so I am certain he got all of the rot the first time. I suspect he just ended up with some bad stock.
Overall, I think it is a decent wood for most cruising boats. It does not have the strength of some hardwoods, but is generally rot resistant. In your situation, I would go with it.
I know this does not address your question about structure on boats over 45'. I think Gord covered that.