The start of something new...

[Dan Miller]

Well, it has been a long time coming, but there is finally a new boat in the works at Dragonfly Canoe. Today we finished lofting out the next addition to the fleet (well, except for the keel rabbet). The goal was to design a canoe for the type of solo canoeing that I like to do (typically in a Peterborough Minetta), but to be built using traditional lapstrake construction. So, starting with drawings of a 16' Rushton Ugo, I've made the following changes (awfully presumptious of me, eh?): shortened the length to 15' (not a big deal, this is how Rushton offered a range of lengths), increased the beam to 32" by scaling the half-breadths, increased the depth by 1-1/4" which makes the depth 12" top of gunwales to top of keel. The canoe was lofted full size and faired, and the results (stations) can be seen in the image below. BTW, if you look at Station 4, you can see the importance of diagonals in the lofting process...

This week we'll finish up drawing that keel rabbet, order some green white oak to be sawn at the mill, and look for a suitable red oak keel plank. If we accomplish all that, we'll be cooking with fire on our return from building 16-30s in Clayton next week.

Cheers,
Dan, whose wife would still really like a kitchen sink...

 

[Dan Lindberg]

Good work Dan,

And, red oak in a boat, even a small one that doesn't spent all it's time in the water? How are you going to seal it so it doesn't take on water and rot?
Sounds like a job for white oak.

Dan

 

[MikeCav]

I was wondering the same thing about the red oak. Whassup?

 

[Dan Miller]

There are a number of reasons for red oak. For one, it is historically correct. It is what Rushton used in his canoes and pulling boats. This is specifically mentioned by Harry Rushton and confirmed by looking at existing boats. White oak has a tendency to twist, which is of great consequence for canoes with wide keels (the Rushton keels are 4"). According to one current builder of lapstrake canoes, white oak would be suitable for keels up to 2" or so, but not so good for wider keels. John Gardner also discusses the problems with white oak for canoe keels in his "More Building Classic Small Craft" in the Four Canoes chapter.

Canoes spend so little time in the water, that if properly maintained and stored. there should be little problem with using red oak (red oak will also take up preservatives better than white oak...

Walt Simmons' book indicates he uses ash, but in my opinion, it is not much more rot resistant, and tends to turn black. I'd consider using black cherry, if I could find an appropriate piece...

Cheers,
Dan

 

[Splinter]

Turning black

Cherry will turn Black too. White Oak is the decay resistant wood of choice for this situation, it will turn gray in about a year or two. The tall ship "The Constitution" which is the oldest active ship in the U.S. Navy is built from 8" x 8" white oak lumber. No rot due to it's closed cel structure and high decay resistance. Red oak soaking in water like that will begin to rot in about a month. But, Dan is right. Due to the very limited time the canoe will be in the water, it isn't really going to make much of a difference which wood is used. In fact, owing to the very deep porosity of red oak it will suck up wood preservatives just dandy. A fun test is to take a piece of the red oak you are planning to use about 1" x 1" x 12" long and put one end into dishwashing liquid, take it out, blow air through the other end. You should get soap bubbles forming on the soap coated end. This wood will take preservatives well. I like Thompsons waterseal myself. When it's completely dry make sure ALL surfaces and edges are well coated with more than one layer of marine topcoat. Pretty shape, this new boat, can't wait to see her. P.S. Do you want me to pick up a sink for you on my next visit out? HOBO (Home Owners Builders Outlet) has some good deals. Will probably be April when I get east again.

 

[Dan Lindberg]

I'm always learning something new, I didn't know either tidbit.
thanks,
Dan


"White oak has a tendency to twist"

"Cherry will turn Black too"

 

[bob goeckel]

a UGO? ain't that one o' them foreign jobs? gonna be tough getting service and parts.

 

[Dan Miller]

Normally I would argue for the white oak over red for the same reasons, but those old-time boatbuilders were a smart lot - if they chose one thing over another, given that both were readily available, there had to be a good reason. Given that the keel in these little canoes is only restrained by 3/16" or 1/4" planking and dainty little ribs, stability is the prime concern. If white oak twists, as it has the reputation for doing, it'll win the battle.

FWIW, the Adirondack guideboat builders used white pine (moderately rot resistant) for bottom boards, and Wilbur and Wheelock used white cedar for their keels. I'll poke around at the museum some next week and see if I can tell what some of the other builders were using...

Cheers,
Dan

 

[Andre Cloutier]

red oak you say?

Dan, I've got a lot of red oak, mostly 4/4 rough , some in widths up to 14", some really long stock
what do you need?
give me a rough dimension and if i can accommdate it I'll bring some down
all air dried, about 15-20 years old
oh and a lot of basswood too...
got a total loss fire today, want me to poke around for the sink in the rubble? single or double?

 

[Louis Michaud]

Dan, you've already said how much you liked the Minetta. Comparing the lines, your Ugo Jr has more deadrise, sharper entry lines, softer turn of the bilges and seems to have less volume in the lower part of the hull. What hull behaviour/characteristics are you looking for (improving on the Minetta?) and why?
I know: BIG question!!!! I would like to learn more about hull design.

Best,

Louis Michaud

 

[Dan Miller]

Hi Louis,

All that is true, plus there is a little less rocker in my new design. What are the consequences? I'm not a naval architect, but (given all else being equal, like hull construction), I expect the finer entry and lower wetted surface to make a slightly faster boat, less rocker and slacker bilge may make differences in responsiveness a wash, my version feel a little less stable when heeled due to the shape of the bilge (but I don't think we're as soft as the Placid/Bell *Fire series). I think it will suit my paddling style - I typically kneel in the bilge just aft of amidships, heeling the canoe some, but I'm not a gunwale-to-the-water person (except when playing dead fish polo...). I'll be curious to hear what others think... Someone like John Winters could digitize the design, run the numbers, and tell you what the performance predictions mean. i sort of understand that part of it, but not well.

However, the other factor infuencing this design strongly is hull construction. Since I am building her in traditional lapstrake, I opted for a hull shape that will be a bit easier to plank up. I think it would be interesting to build a Minetta as a lapstrake, but after I get one or two under my belt... Working from the Rushton drawings means I have less to work out up front (keel and stem rabbets, and other construction details unique to lapstrake canoes). There weren't a whole lot of options, as the vast majority of traditional lapstrake canoes were designed for smaller people who paddled in a different manner than I do. Nearly all are for double-bladed paddling, the few that were more "Canadian" in style (like the Skaneateles Onondaga model) are quite rare and non one has taken lines (yet). I've always liked the Ugo, and as an added bonus, I can stretch the molds back out to 16', deck it over, and have my own version of the Nomad sailing canoe.

Cheers,
Dan

 

[Douglas Ingram]

That's looking good Dan.

I like lofting to full size too. You get a good feel for the shape of the canoe that way. Can't get the same feel using computer lofting.

This is a nice way of accomplishing both the goals that you spoke to me about over the phone, a nice 15' canoe that you'll enjoy paddling, and working in the lapstrake method that you want to do. Its also a nice combination of traditions, the Rushton and the Peterborough.

Looking at the drawing it shows a strong link to the cedarstrip shapes that Peterborough used. Its actually quite similar to the Minetta, even though the turn of the bilge is softer. Shouldn't be a problem in a 32" beam.

I do have a small concern about the transitions from tumblehome amidships to flare, and then back to tumblehome approaching the stem. Its a pretty significant degree of change. Before you commit you might want to carve a scale half-hull to see if your drawings look like the canoe that you've conceived of in your mind. A nice half-hull model would also look so nice on your shop wall!