Pierre-Yves Gabi cartops his AF3 in Switzerland!
Contents:
Contact info:
Jim Michalak
118 E Randall,
Lebanon, IL 62254Send $1 for info on 20 boats.
Jim Michalak's Boat Designs
118 E Randall, Lebanon, IL 62254
A page of boat designs and essays.
The 15aug02 issue reruns an article about making your own oars. The 1sep02 issue will be about boat camping.
ON LINE CATALOG OF MY PLANS...
... can now be found at Duckworks Magazine. You order with a shopping cart set up and pay with credit cards or by Paypal. Then Duckworks sends me an email about the order and then I send the plans right from me to you. The prices there are $6 more than ordering directly from me by mail in order to pay Duckworks and credit charges. The on line catalog has more plans offered, about 65, than what I can put in my paper catalog and the descriptions can be more complete and can have color photos.
|
|
Left:
Pierre-Yves Gabi cartops his AF3 in Switzerland!
|
|
|
Making Oars
I decided to rerun these rowing articles that first appeared here in the winter of 98-99. I've left out some of the details that appeared in those issues and added other details.
MAKING A SET OF OARS....
I'm going to show drawings for 7' oars which are about the most useful length for me.
WHAT KIND OF OARS....
The oars I make are really derived from the patterns of the late Pete Culler. They are characterized by having heavy square looms inboard of the locks and long narrow blades in the water. An example is shown in Figure 1.
The square looms are easy to build, help balance the oar, help locate the oar in the locks, and keep the oar from rolling around on the wales.
The long narrow blades go against modern thinking of spoons, but for long distance rowing, long and narrow is the way to go. The average mortal can only pull so much of a load, in spite of what an Olympian might do. The Culler blades can match the mortal's pull. They might slip a bit when starting a heavy boat from a standstill, but once up to speed, the have full grip on the water. They balance better. They are less fatiguing. They have less windage. By the way, the oars of traditional Irish caurrahs have no blades on their oars. Neither do the paddles of some traditional kayaks.
WHAT YOU NEED...
Oars are made from four materials - wood, glue, leathers and varnish.
For wood, I use 1x6 pine boards. The pattern shown in Figure 1 will just barely make an oar from a 1x6. I try to buy a single board long enough to get out both oars. For example, for a pair of 7 foot oars, I buy a board 14 feet long if I can. That way the oars will be a close match on weight, stiffness, and color I like to use soft wood like pine, It is easy to work and makes a light oar. It need not be clear wood although clear is easier to work Small solid knots are fine and look good too. I've never worried too much about grain because the sticks get laminated and tend to stay straight. But the straighter the grain the better.
For glue I prefer plastic resin "Weldwood" glue and doubt if there is anything better for making oars. Pour some in a cup and squirt in cold water until it has the consistency of normal woodworking glue like "Elmer's. I've found it to quite true that this glue will not set properly until it is a t 70 degrees F for twelve hours like it says on the can. But don't hesitate to use epoxy if you already have it on hand.
For leathers I don't use leather. I bind the 8 inches just below the square section of the loom with synthetic mason's twine, about 3/32" diameter. It lasts for years.
For varnish I use ordinary oil based spar varnish.
Now let's talk tools. The tool I use the most in making oars is a bandsaw and I hate to say that because it's not a cheap or small thing that everyone will have. The problem is that you've got to saw a 2-1/4" thick blank. Hand saws will work and the effort should get you in shape for rowing. After all, oars were invented long before the bandsaw. But I see Dave Carnell has built oars using his table saw and others have built oars with a sabersaw.
HOW TO BUILD...
First cut the 1x6 boards to the proper length. lay out the centerline with a straight edge. Then draw the pattern for the center piece, the one with the blade, around the centerline. Cut out the center lamination following the line closely with your saw, because the outer laminations of the blank are made from the off fall and there isn't much extra.
You can draw patterns of the outer pieces and cut them out. But it's easier to glue the pieces directly to the center piece and trim them after the glue cures. Trial fit the outer pieces. You may have to trim them for the proper shape where they blend into the blade area of the centerpiece. When you are satisfied, butter them up well with glue, and clamp them in place. You may need to tap in a a light temporary nail to keep the pieces from sliding around on each other because almost all glues are quite slippery until they start to set. Try to get glue squeezed out all around. And be sure the blank is resting straight while curing. Walk away from the blanks until the glue has cured hard.
After cure, trim the outer pieces to match the centerpiece. Use a plane and sander to work these pieces to their final lines, being careful that these faces remain square to the other two unworked faces.
Now cut the two unworked faces of the handle and loom of the oars to their final dimensions. Draw centerlines down the two worked faces and lay out the shape of the handle and loom. Cut to the lines and sand smooth. At this point the cross section of the oar from handle to loom is square.
The oar drawing shows how much of the loom is left square. The rest is to rounded. You start by drawing lines on handle and loom that allow you to make the cross sections octagonal. You can draw them using the gadget shown in Figure 2. Then cut down to the lines with a half round rasp where the lines blend to the square section of the loom. Then use a drawknife or plane to remove the rest of the material down to the lines along the shaft. Now she's eight sided. To round it you're supposed to sixteen side it and then round it out. To tell you the truth, I leave mine eight sided, including the handle and the area which fits in the rowlock.
Lastly you need to trim mass out of the blade. I plane the blade down so its edges are 1/4" thick. Then I use the front roller of my belt sander to hollow the blade slightly on either side of the center, leaving a ridge in the center.
I think the only critical part of these oars strength wise is the 1-1/4" section where the blade meets the loom.
Give the oars a good overall sanding, but leave the handles rough.
Wrap the rowlock area, from the square section down 8 inches toward the blade, with mason's twine. Wrap it tightly and use knots to secure it.
Give the oars three coats of spar varnish. That includes putting varnish on the twine binding. It will go a long way towards holding the binding in place. Don't varnish the handles.
An easy and effective "button" can be made be added to the bound area, to provide a stop which will locate the oar lengthwise in the lock, by wrapping it tightly with three wraps of 1/4" shock cord, and tying the cord with a square knot. If the tension in the cord is right, it will stay firmly in place while rowing and yet allow repositioning up and down the bound area to change rowing leverage when required.
A ROWING SEAT/DITTY BOX....
Figure 3 shows a rowing seat/ditty box that I've been using for years. You might have to tinker with it a bit to get it to fit your butt. As for the height of the box, it is nice for a bar placed across the rowlocks of your boat to cross you at belly button height. That would include any padding on the seat such as a flotation cushion which you should have on board anyway. For that matter a stack of two or three stiff flotation cushions can make a pretty good rowing seat.
Here is what the seat looks like for real, this one about 15 years old now. Here are some things you might keep inside the seat: spare oarlocks, a knife, some line, sunscreen, Vasoline, binoculars, compass, whistle, and some energy bars. Always take a lot of drinking water with you also when you go rowing.
OARLOCK SOCKETS...
If your hull's side have limited flare, say less than 15 degrees, you can make some cheap oarlock sockets that are as good as store bought. I got the idea for these, plus the oarlocks that follow, from Phil Bolger who used them on his Spur 2 rowing boat that appears in his book BOATS WITH AN OPEN MIND.
Here is how it's done.
What we have here is simply two metal plates bolted to the wale with the proper sized hole (usually 1/2") drilled in each. Phil had his made of stainless steel. I made mine out of aluminum and have had no problems. I used an aluminum yardstick of the type carried by lumberyards for use with drywall as the basic material. I think the metal is about 1/10" thick and about 1-1/8" wide. I cut the aluminum to 3" lengths, stacked them up and drilled the oarlock hole and the bolt holes all at the same time. Filed off any sharp edges. Clamped the plates in the proper position and drilled the wooden wale. Bolted the plates in position and that's it. These work well because the oarlock bears on the metal parts which are about 1" apart, a bit more than the usual shallow factory sockets. So far I haven't worn them out. By the way, it helps to grease any oarlock from time to time, ordinary Vasoline works well.
BOLGER OARLOCKS...
I haven't tried these but Phil swears by them. It is really a thole pin with a bracket to retain the oar. Phil has always said that thole pins are better than the usual factory oarlock where the oar centers directly over the rotating pin. With a traditional fixed thole pin the oar rotates around the fixed pin as it bears against it and Phil says that is a better motion than with the factory oarlocks. The pin shown here could also be fixed, the bracket rotating around the pin with the oar! I should try these.
NEXT TIME...
...boat camping.
Contents
Twang
TWANG, POWER SKIFF, 13' X 4', 100 POUNDS EMPTY
Twang is a small light power skiff, light enough to cartop if you keep your mind on weight as you build and if you can figure out a way to carry your motor and fuel in your car. It would also suit well the needs of someone who wants to carry his boat in the back of a pickup truck. She is 13' long, 4' wide, and I'm thinking about 100 pounds stripped.
I've never seen a hull shaped like this before. Look closely at the lines and see that the bottom is dead flat lengthwise for the last 10', and also flat across for the last 7'. That gives the boat good capacity and I'm thinking the ability to plane with a small motor, say 5 hp with a light skipper. So that much is about the same as with my little JonJr. design. But the bow here is pointed and designed to meet a wave with a deep V shape and hopefully be softer riding than a jonboat or flat iron skiff. There is bound to be turbulence where the deep V meets the flat bottom but I'm hoping it won't be a factor on plane since only the aft half of the hull will be in the water then. I could be wrong and we might find out why I've never seen a hull like this. I'm quite certain it is impossible to come up with a new idea about hull shaping because everything has been tried in the past by good people. But new materials and techniques come along so that ideas that didn't work a generation ago might now be valid.
The hull is made with four sheets of 1/4" plywood and I think it will be easily made. The sides and bottom will be a piece of cake. The deep V bow is made from two simple pieces of plywood taped in place. I tried this design first by warping the bottom into the shape of the deep V and got the shape I wanted on the model, but felt quite certain that the amount of plywood torture needed would not please many. As is, there is almost no twisting in the panels. If this little design works I would waste no time trying it at 16' x 5' with heavier plywod. By the way, trying thicker plywood on a design with lots of twisted panels can be impossible. Even going from 1/4" plywood to 3/8" about triples the force needed to twist the panel into shape.
In my opinion these little boats aren't safe with big motors. I'm suggesting 5 hp. They also do quite well with small motors, say 2 hp. The low powered boat would be faster if the stern were swept up to meet the waterline and didn't drag the stern through the water, but only if the skipper sat well forward so that the boat really trimmed that way. Here is what really happens when someone puts a motor on a good rowing boat - one that has the swept up stern. No one ever puts controls on the boat that allow the skipper to sit forward for proper trim. The boat sits very badly trimmed down by the stern to the point where the skipper can hardly see over the bow. And when the power is applied the situation is a lot worse. So if you plan at all to use a motor, build a power boat like Twang and not a rowing boat. If you plan to never use a motor build a good rowing boat. Oars and motors don't mix well at all. Good rowboats never power well and good power boats never row well. In small boats at least, I know of no successful row/power boat. Remember that arm power might be 1/10 of a horsepower, and the smallest motors are ten or twenty times that.
Plans for Twang are still $15 until one is built and tested.
Prototype News
Some of you may know that in addition to the one buck catalog which now contains 20 "done" boats, I offer another catalog of 20 unbuilt prototypes. The buck catalog has on its last page a list and brief description of the boats currently in the Catalog of Prototypes. That catalog also contains some articles that I wrote for Messing About In Boats and Boatbuilder magazines. The Catalog of Prototypes costs $3. The both together amount to 50 pages for $4, an offer you may have seen in Woodenboat ads. Payment must be in US funds. The banks here won't accept anything else. (I've got a little stash of foreign currency that I can admire but not spend.) I'm way too small for credit cards.
Here are the prototypes abuilding that I know of:
Electron: The California Electron in the water. Right now a four cycle 2 hp outboard has been purchased so the original electric idea may wait a while. I'll have a writeup on this one in a few weeks.
Shanteuse: The stretched (16' to 24') Shanteuse still awailts its windows. Here it is on trials for Florida river cruising.
Sowsear: Haven't heard anything lately of the Pennsylvania Sowsear.
AN INDEX OF PAST ISSUES
Hullforms Download (archived copy)
Plyboats Demo Download (archived copy)
Brokeboats (archived copy)
Brian builds Roar2 (archived copy)
Herb builds AF3 (archived copy)
Herb builds RB42 (archived copy)