White cedar problems

[John Michne]

Back about 4 or 5 years ago, I decided to figure out how to plank a guideboat rather than strip it. I used flat sawn white cedar, which I had on hand. Big mistake. I managed to plank it using the Grant lap, varnished it, and traded it for a new custom-built fiddle. The boat is now back in the shop with some serious problems. The flat sawn white cedar cracked like crazy. Last year, we filled all of the visible cracks with thickened epoxy, but more cracks opened up over the winter. Some of the filled cracks even opened up further.

The plan is to sand the varnish off the outside, fill the cracks with Durham’s Rock Hard Water Putty (or epoxy?), sand it smooth, lay on 4 oz. fiberglass/epoxy, and finally paint it.

All of the brass, gunwales, and decks were easily removed, and the sanding is just over half done. I invite the forum to make suggestions, and I will post progress.

Lesson learned – white cedar is fine on a stripped boat, but don’t even think about planking with it.

 

[Dan Miller]

Sorry to hear you had problems.

White cedar itself is not the problem. Thousands, if not hundreds of thousands of small craft have been built using white cedar (both northern white and Atlantic white) for planking.

Flat sawn is definitely not your first choice. However it does appear with regularity on factory-built lapstrake canoes, including Rushtons. Ideally you would find white cedar stock that is live-edge and sawn through-and-through. Varying sweeps in the planking stock allow for laying out so that the sweep of the plank follows the grain.

Did you back out your planking, or force the cup into the planks? If the latter, the stresses of trying to straighten back out would lead to cracking, especially with flat sawn stock. Backing out is an essential step in any type of smooth-lap construction.

The Grant lap is also more prone to cracking than a feather lap, due to the hard corners in the lap.

What were the storage conditions? If heated, the boat dried out and that led to cracking.

White pine was the guide boat builders planking stock of choice. Possibly it resists cracking more than cedar. Durant claimed the builders chose pine because it absorbed less water than cedar. Most probably, it was because it was readily available throughout the Adirondacks.

 

[John Michne]

Thank you for your reply, Dan. No, I did not back out the planks. I recall reading somewhere (in Durant?) that Hanmer did not believe in backing out. Who am I to question the old masters? I also figured that since the white cedar was more flexible than pine or red cedar, it should conform to the curves of the ribs fairly well without backing out. It is interesting to note that there were a couple of planks that were in effect quarter sawn, the result of flat sawing the log through and through. Those planks did not suffer any cracking.

The boat I built following was planked in quarter sawn Eastern white pine, again no backing out, with the Grant lap, and without problems. I do have another boat planned, with a rib set and spruce stems ready to mount. I don’t have the planking stock yet, but plan to experiment with backing out, at least at the turn of the bilge. I have a curved sole and blade plane from Lie-Nielsen that showed promise on some test pieces.

With every boat I build, I learn something new. Someday I’ll be good at it.