Lapstrake construction

Hi Folks,

I'm new at boat building but have been woodworking for 25+ years. I'm researching how to build a Rangeley Boat. I have found some great resources. The length of the Rangeley I'm considering is 17 feet long, question i have is do I have to have 17' planks for this job, I have not yet found where they talk about how they handle butt joints for lapstrake contruction for shorter planks. I've order a few more books from the library to research but started to read on this site and finding quite a bit of info. Any help would be apprecited.

Thanks

 

I do it two ways. Butt joints in small hulls creates hard points, especially if you do not intend on using any fiberglass and fairing compounds. These are done with a hand or power planer and then cleaned up by a finish sander. You can do scarf joints as I am doing and is described in this website. In the beginning you can do full sheets with 8 to 1 scarfs. Thats 8 times the thickness of the plywoods. This takes some practice before you do it on expensive woods or good plywoods. Read this link and there are others across the web. You do not need to worry about doing step scarfs, since you have little control over alignment if the scarfs end up a bit out of square. For beginners a smoothe taper is a great way to start.


http://www.shopbotprojectwizard.com/ProjectInfo/ScarferDesigner/

 

Wonderful, easy enough, thanks

 

When you are doing your scarf, use a backing board across the intended joint under the bottom side that makes a more uniform seam when planning and sanding. In plywoods that has the malamine glues, with no color, unlike the plywood with rescorcinol glues, that gives you a better showing of uniform layers, its a bit harder to follow.

 

Tell me Oyster, can I use just a waterproof woodworking glue for this joint (like Titebond) or am I now into a whole different set of glues for watercraft.

 

Well I have only used rescorninol glues before epoxy. I have used Titebond in strip planked canoes and in strip planked construction in small craft construction. You are talking about a very nice hull design. I would not trust the laps to Titebond, in my opinions. Others may not agree. I still go back to the idea that material costs is a very small part for the amount of hours spent to build these hulls. Titebond does not varnish well if you go the clear wood approach, on any project.

 

What do you recommend, I'm looking at Gardner's design of the Rangeley and I'm waiting for a few other books to get a better understanding of the boat building process. So far looks like my choice of wood will be white oak. Believe it or not I spent the first 5 years of my professional career as a naval architect working on submarine hull design, seeing mold loft lines brings back good memories.

 

If you are asking me about what kind of boat? Thats not for me to even address. Choosing a boat is entirely a personal choice depending on your use and tastes. I personally would use epoxy for any scarf joints with plywood construction. I take it that when you speak about white oak, you are thinking white oak for framing, as white oak for planking is surely not to be used.

In framing, white oak has some issues if the oak is not seasoned or carry certain grain orientation. But for any stem bending, white oak of ash, all green lumber is the best for that job.

 

Actually I meant white oak for the planking, I guess what I have read so far from Gardner's points to white oak. He does mention paying attention to grain patterns and scarfing as needed to ensure straight grains but maybe modern day plywood will save me a lot of pain.

Still researching and learning, thanks again.

 

We really need to look at the specific plans and your intent on just creating a neat and unusual boat or making an attempt to recreate a specific hull steming from some past lusting.

Oak for planking was used overseas in the Eurpoean hulls, which is not really necessary in your area. Most the the hulls also stayed in the water keeping the changes to a minimum.

 

So if you were to plank a boat similiar to this that would be used in fresh water only what would you recommend for planking, plywood and if not plywood what type of solid wood? I read that ash can rot too fast, northern cedar or fir?

 

Cedar is still the wood of choice for me. We use white cedar or in some cases its called juniper in some circles. The western red cedars or port orchard cedar is more stable but harder to come by on the east coast. There are many names that the cedars go by, so check with some of your local boat builders in your area. Do a bit of leg work or calling. I would begin by checking with the Apprentice Boat in Maine. Just make sure if someone say use white pine its not the generic type from your local big box store. There is a difference. If you go with plywoods, Okume 1088 is the standard followed behind by Meranti which is heavier and does not bend as good in extreme curves.

Go to this link an type in your zipcode for selected materials as another avenue in the beginning.

http://www.woodfinder.com/

 

I am also new to boatbuilding and am presently working on a 12' lapstrake sailing dinghy. The problem is that the marine plywood I got only comes in 8' lengths. The way you solve the problem is to "scarf" the ends, that is plane them at an angle so that when you finish, you can turn them over and "overlap" the scarfs and join them with epoxy. The book that I am using as my building guide is "How to Build Glued-Lapstrake Wooden Boats" by John Brooks. It depends on the thickness of the wood for the angle of scarf.

flydog

 

TiteBond Original, is a basic interior glue and will release at the hint of moisture. TiteBond II is a type 2 water resistant glue that is as the name suggests, water RESISTANT and will release, but needs a longer soaking. TiteBond III is a type 1 water proof glue, but type 1 can't tolerate complete soaking or total immersion in water, it will fail. All the TiteBond glues are not rated as structural adhesives, so be warned. TiteBond III is great for above the waterline use, especially if glue joint color is important (bright finishes). With all TiteBond products, use fasteners to insure things stay together, with a glue line to lock the joints.