Garth Battista's Cormorant crew, at sea.
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.
(15Aug05) This issue will rerun the taped seam essay. The 1 September issue will continue the Bobsboat series.
THE BOOK IS OUT!
BOATBUILDING FOR BEGINNERS (AND BEYOND)
is out now, written by me and edited by Garth Battista of Breakaway Books. You might find it at your bookstore. If not check it out at the....ON LINE CATALOG OF MY PLANS...
...which 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.
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Left:
Garth Battista's Cormorant crew, at sea. |
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Taped Seams
HISTORY...I remember seeing taped seam construction first in an article in the old Small Boat Journal about Sam Devlin's efforts. That was probably about 15 years ago (time flies). But by then the method was old in England. I think it was "invented" by an Englishman in the late '50's and was quite common there by the 70's. The Mirror dinghy was done that way with kits meticulously made from plywood with notches and tabs to fit the pieces together like a balsa model airplane kit. I visited England in 1982 and saw hundreds of Mirrors stacked on end at Portsmouth. Around the same time kit makers like Clarkcraft were selling kits of kayaks made that way but they called the method "sewn seam" which I think threw some of us off. "Sewing plywood together with wire - that sounds hard!" I said to myself. Harold Payson and Phil Bolger tried it in the early 80's with several designs that are still around. Harold called it "tack and tape" because at the time he didn't like using wires to temporarily fasten the panels together. He used small nails and adhesive tape, then hot melt glue, but eventually came around to using wire like everyone else.
My own taped seam history started about 1985. I made a Payson/Bolger dory with taped seams even though it was originally designed to be made on a ladder frame with chine logs in the old fashioned way. Payson's book "Build Your Own Boat" had the complete dory plans and also included the side panel expansions! It was easy to build a taped seam version with no ladder frame. Harold used polyester resin in his projects probably for the same reason others have used it - it's cheap and available. So I used it too on that dory. I tried ordinary automotive Bondo to fillet the seams instead of the resin/filler mixes that Payson advised. That boat had but one layer of glass inside and out. I used it for about five years until it got crushed by another boat in a tornado. The transom tapes were ripped (but the polyester resin held), and the boat was sort of opened wide. I gave it to Jim Huxford who repaired it and rowed itfor a few more years. It might still be around somewhere. In many ways my boat Sportdory is a rework of that old dory.
Next for me came the Payson canoe, multichine taped seam boat. Also built of cheap plywood with polyester resin and automotive Bondo in the late 80's. It eventually went to Bob Archibald who may still have it.
Next for me was Piccup Pram in 1989. Cheap plywood and polyester resin and Bondo again. I still have it and use it. It's seen a lot of use.
Next was Roar (which evolved into Roar2) about 1990. Cheap plywood and polyester resin and Bondo. Still have it and it has seen a lot of use.
Next I think was Toto which sort of evolved from the Payson canoe. Cheap lauan plywood with epoxy resin this time but still with Bondo fillets. Still have it and it's seen a lot of use.
The last was WeeVee which used cheap lauan plywood and reverted back to polyester resin and Bondo. Still have it but it hasn't gotten the use of the other boats.
"What's with all the polyester resin and Bondo?" you ask. Anyone who mentions using these in the rec boatbuilding newsgroup gets pounded and made fun of. Even 15 years ago Payson was attacked for building with polyester. I didn't know any better and have really had no troubles. Whenever I use one of my polyester boats I tell it, "You'd better start falling apart soon. You're making those experts look bad and they are going to pound me on the newsgroup and make fun of me." So far my boats haven't listened.
Polyester has certainly worked OK for me. My boats are stored under cover as a rule (although some have been outdoors for months at a time). That may be a factor in their longevity with polyester. Where I live you can never expect to get your money back on a homemade boat, even the cost of materials. I think when we started 15 years ago we got polyester for $13 a gallon (good stuff too) while epoxy went for about $70 a gallon. Now we know where to get much cheaper epoxy. So now I advise epoxy and it really is better. Of course if you are using expensive plywood, etc., you need to use epoxy.
But now to the main story - how I tape seams.
SECURING THE JOINT WITH WIRES....
(This is how I do it. Others have their pet methods.) Not much too it. My boats are all designed from the inside out, so to speak. The dimensions are arranged such that the panels should make kissing contact on the inside edges as shown above. Usually the project is upside down at this time, sides, bulkheads stem and stern fastened together, and you are trying to put the bilge or bottom panels on with taped seams. You put the panels into position and drill pairs of holes about every 12" around the perimeter, about 1/4" in from the edges. You take pieces of soft wire, I prefer stainless steel aircraft "lock wire" but almost any wire will work if it is pliable, and cut lenths about 6" long and form them into a long U shape like a staple. Get inside the project and push the wire staples up through the holes so that the ends now stick out through the outside. Get outside with a pair of pliars and twist the wires until they tighten the panels together. If you overtighten you might break the wire or tear the wire right out of the wood. Eyeball the joints to make sure they are fair. You can open a joint up to maybe a half inch if it will help. If two panels are binding too tightly, you can run a saw down the joint to loosen it up. I think a small gap or V is preferred because it allows resin to flow in and seal the ends of the plywood. But the joint fit is really not too critical.
When all the panels are wired in I like to go over the outer joint with duct tape to further secure things and to provide a dam for future flowing fillets. Then flip the project upright. Here is what the prototype Larsboat looked like at this stage. You can see the duct tape and can make out the wires.
There are variations allowed of course. The spacing of the wire twists can be anything needed to secure the panel into position. You may need more wires in places. Some folks don't use wire. John Bell used nylon wire ties on his Sportdory as you see here:
Not all panels are edge to edge, of course. Bulkheads are sort of T joints and are a bit trickier to fit. They would join like this:
THE INNER SEAMS... 
Flip the boat upright. Prepare to fillet and tape the inner seams by pushing the wires on the interior hard against the plywood with a screwdriver to make them easier to cover. (One disadvantage of using nylon wire ties might be that they won't stay hard against the plywood.)
Then precut the fiberglass tape to length and lay the pieces out in a logical way so you can grab them quickly when needed. I always use 3" wide glass tape. It has no adhesive but is only called tape because of its form. It's edges are treated to prevent unravelling. When loaded with set resin the edges will be bulkier than the center of the tape, leaving a ridge. Some folks don't like the ridge. Some folks cut glass cloth into strips to avoid the ridge. I've tried that too to it unraveled and I ended up with a lot of glass hair flying around. I prefer the ridge which is easily ground down after the resin sets.
THE REAL TRICK TO GETTING A GOOD TAPED SEAM...
...is to do a seam all at once if possible. That would mean putting down the fillet and then the tape straight into it before the fillet sets. If more than one layer of glass is involved you put the extra layers right onto the first ones before they set. This way you avoid all the nasty sanding you face if you let a layer cure first. (Any cured resin system must be sanded before applying another layer, or paint.) It saves a tremendous amount of work. And you can be sure the whole thing is bonded together. So when you start you must have all you stuff together and ready to go.
In epoxy here is how I would do the job. Mix up some unthickened slow setting epoxy and brush it on the joint with a disposable bristle brush to "prime" the joint. (Some say the prime is a waste since epoxy doesn't really penetrate wood as some ads imply.) Mix up another batch with filler to make filleting mixture about as thick as Bondo. I think most any common filler is OK since you won't be sanding it. See Dave Carnell's page down in the links to get his view on epoxy and fillers. Lay down a fillet of the thickened epoxy over the joint and right over the wires. For a filleting tool I would recommend a tongue depressor 1" wide. I've heard a 3D tool like a tennis ball on the end of a stick is even better. In my view the fillet has to be there for strength but it should not be too large, say no more than 1" wide. It need not be perfectly smooth now but you will have to scoop up stray globs with a putty knife. The fillet should look like this:
Next brush some more thin epoxy over the joint and put the tape straight on top. Brush in more resin to saturate. The tape and the brushing will help to smooth out the fillet. Doing it this way you will most likely need to do short stretches at a time, maybe three feet. No problem with slow epoxy. Just do a stretch and pick up again at the unfinished end. When this all cures you will have a good interior joint with no sanding!
Here are two possible problem areas: One is where a temporary form blocks the tape job. Let it go for now and just end the tape an inch or so each side of the form. Finish later when the outside is done and the forms can be removed. Second is at corners such as where side bilge and bulkhead all meet. Fillet the corner with putty. Cut the tapes such that they will all overlap about an inch at the corner. Paste them down one by one into the corner. You will find that the tape is flexible enough to conform to the corner shape and yet the overlap is plenty to provide continuity.
Here is how I would do the job in polyester. The Bondo will usually set faster than you can slap down the tapes with polyester resin. I'll bet an expert would know how to catalyze the Bondo and resin such that you could get the thing to cure all at once as with the epoxy. You might experiment. Unlike epoxy, with polyester you can vary the catalyst to get different curing times. If you don't feel comfortable doing that, do this: Make the fillets in Bondo and let it cure hard. Sand it smooth with rough sandpaper, either a strip rolled into a tube or taped to the edge of a board rounded to the proper radius. Another handy way to sand the interior fillets is with a 2" rubber disk in an electric drill with very coarse paper. Then paste the tapes down with polyester resin as with epoxy. (On Toto I pasted the tapes down with epoxy resin over the Bondo joint.)
TAPING THE OUTER SEAMS....
These are simple compared to the inner seams.
Snip off the wires as close to the wood as possible. Some builders pull the wires out, sometimes first heating them, but I never had consistant luck with pulling wires. Stainless or copper wires left inside won't rust. Plain steel wire will rust although that is really a only cosmetic problem.
Fair the outer seams with putty as required. Most likely you will have to let the putty cure hard and sand to shape, unlike the inner seams. Radius the seams too - you don't really want a crisp sharp edge.
It's best to mask off the sides or any place the resin might dribble and drip. It will always dribble and drip when you aren't looking. Don't expect to outsmart it.
Next cut your tapes to length. Brush the seam with epoxy and slap the tape down and saturate the tape with more epoxy brushed in. Like this:
Usually I advise more than one layer of glass on the outer seams to allow for some abrasion. Often I will put a layer of glass cloth over the bottom panel for the same reason. I have never glassed the total exterior or interior of any of my boats. The second layer goes right over the first before the first cures. Saturate well. Look for dry spots that will appear white whereas saturated glass appears clear. The edge of the second layer should be staggered a bit from the first layer like this to prevent a big ridge on the edge.
FINAL WORK...
After cure, sand lightly but not through the glass. I do feather out the glass edges with a rubber disk sander in a drill with pretty coarse paper. Then I give the tapes a light layer or two of filler to fill any weave followed by another light sanding. Then I try to accept any remaining imperfections and paint the hull. You can wear yourself out being a perfectionist about this and you are welcome to do so. If your boat gets hard use you won't notice those imperfections at all after once or twice to the lake.
And remember those places where the temporary forms stopped the interior tapes. Once the forms come out, sand and rough up the ending points, fillet and tape those final gaps.
YOU'RE DONE!
NEXT TIME...
...We'll figure out the structure for Bobsboat.
Cormorant
CORMORANT, CABIN SAILBOAT, 32' X 8', 2500 POUNDS EMPTY
Cormorant is the largest boat I've ever designed. I always warn folks to think twice and three times before building a big boat because you can buy a good used glass boat for less, maybe a lot less. But a homebuilt boat can have features that aren't available in a production boat and so it is with Cormorant. This one is really a 20% enlargement of Caprice.
Straight enlargements rarely work perfectly and so it was with Cormarant from Caprice. (Don't forget that Caprice was an enlargement of Frolic2, etc., etc., right on down to my Toto canoe.) In this case I narrowed it from a straight enlargement to keep the width within simple towing limits since this large boat is supposed to live on its trailer most of the time. The layout is quite similar. The idea is that the adults sleep in the center cabin and the kids sleep in the forward room.
Like Caprice, Cormorant has water ballast, over 1000 pounds of it. Total floating weight with family is going to be up to 4500 pounds. You don't tow a boat this large behind a compact car but I think towing this sort of weight is common today, all done with expensive large trucks I'm afraid.
The sail rig looks pretty modest with a 207 sq foot main. I'll bet it is enought since this shape is easily driven. I don't think you can go any larger and still hope to handle it without extra crew and gear.Tthe lug sail shown is similar in size to Bolger sharpies and they seem to get by OK. Experience will show if it is too big/too little.
Constuction is taped seam, with no jigs or lofting. Unlike smaller designs this one does not come with a plywood panel layout drawing. Over the years I've learned two things about the ply layout page. First is that almost no one uses it. Second is that with a larger boat the work of finding and drawing and fitting all the pieces to the boat on scale plywood sheets overwhelms all the other work. So part of the deal with doing the design was that there would be no plywood layout drawing. However this is still a true "instant boat" in that all of the parts that define the boat are drawn in detail and you can scale them up on plywood, cut it out and fasten together with no need for lofting or a building form.
Garth Battista, who is a book publisher at Breakaway Books where he publishes sporting books including my Boatbuilding For Beginners (And Beyond), is a true boat nut and has worked himself up from dinghies and canoes to the big Cormorant. He took it initially on a quick shakedown run on a lake near his home and shortly later to Long Island Sound for a week with his family. Here are his comments:
"We had an amazing time living aboard Cormorant (christened "Sea Fever") in Provincetown harbor for 5 days. The tide there was rising and falling about 12 feet a day with the full moon. We'd be high and dry up on the beach for breakfast, swimming off the boat at lunchtime, walking the flats again by dinner. It was a blissful time for me and my wife and two girls. We moved around, took little sails here and there across the harbor (West End to Long Point, then to the lighthouse, then to the East End, etc.) anchoring here and there, usually just running it aground as the tide allowed and staying for a while. Many shells were collected, and tidal pools investigated. Of all the harbors I've ever seen, it is the most alive. It's a couple of miles across and fresh sea water flushes the whole place twice a day. The number of snails, clams, crabs, fish of all sizes, mussels, eelgrass, etc. was just mind-boggling. On high tides I'd go spearfishing (many attempts, no luck) where at low tide I'd been walking around.
We rigged a 8' x 15' white tarp with tent poles running crosswise as a canopy over our cockpit and hatch, supported along the mast folded down in the tabernacle, so we could escape the mid-day sun. Most days were hot and humid and mild, with only gentle winds. We rode out a nighttime thunderstorm with no trouble, just stayed up and watched the lightning. We attended a few wedding-related events, just walking ashore for one party, and for the wedding itself we returned late at night and rowed our dinghy out to the boat, our sleepy children just awake enough to get themselves aboard.
For our last two days we gave up the shallow-water life and sailed from P-town down to Wellfleet, about 7 miles, surfing along on gentle 3-foot waves with a following wind. We beached the boat at Great Island, walked the beach, had a picnic dinner, swam and played, spent the night, and left the next morning at 6 a.m. to beat the falling tide. Our weather radio mysteriously quit working that morning, so all we had was the prior day's forecast of 10-15 knot winds from the SW.
The wind had shifted into the west during the night, so we had to beat out of the harbor, and once we turned north to return to Provincetown, huge rollers were coming in off the bay, more or less directly into our port side, lifting us, rolling us, occasionally breaking and spraying water into the boat. We stayed well offshore to avoid the breakers in by the beach -- but with the falling tide it seemed that we needed to be nearly a mile out. It went from exhilarating to worrisome to mildly terrifying as we neared P-town and the wind kept picking up, past 20 knots to 25 and higher in gusts, and the waves just kept growing. The swells were in the 8-10 foot range, with a high percentage of them breaking at their tops, whitecaps everywhere.
But bless this boat! With its 1000 lbs. of water ballast, and the leeboard mostly up, we were able to bob and roll and slide over nearly all the swells. The worst of them were very steep and threw us sideways, maybe tilting us to 40 or 45 degrees briefly. We had two reefs in the main and the mizzen rolled down to about half-size, and still we blasted along on this nasty rollercoaster of a beam reach. It was the sort of trip that would be scary fun if it was just you and a buddy, but it's awful when you have your loved ones aboard, and you wonder who might get thrown overboard, and how you'd managed a rescue in the rough conditions.
Anyway -- the white knuckles got to relax as we finally made it past the P-town breakwater, and with great relief ran her aground out on the flats. The gale (or near-gale) continued to blow all day, kicking up 3 and 4-foot waves even in the protected areas of the harbor. The only boats we saw going out were an 80-foot schooner and a big whale-watch boat. A lobsterman we talked to later said he'd stayed in as it was too rough to check his traps.
We had a hell of a time taking the boat out and getting her on her trailer for the trip home -- but all worked out in the end, with the assistance of some very kind strangers; and I'm left with the memories of incredibly happy days. -- And an incredible boat.
All best, Garth
P.S. Jim -- I should also mention that on Sunday afternoon as we turned the corner from our run down to Wellfleet to the close reach upwind toward the inner harbor, the boat just drove perfectly. It seemed we made 40 degrees off the wind. That maybe wishful thinking, but it was an angle far better than I'd imagined a lugsail could manage. It was a joy to sail, in all conditions. My hat is off to you.
P.P.S. The number of people who came over to admire the boat and exclaim at its uniqueness, its coolness, its obvious functionality -- well, they were beyond count. "
Plans for Cormorant are $60 when ordered directly from me.
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.
The AF4G is done and launched. Writeup next issue:
The out West Picara has its roof and some major sail rig bits done:
The down South Picara is getting its innards done.
This long and lean project is a 19' version of Toon2. I'm told this one is more or less complete, left with the 15 % of the work that takes 85% of the time.
This is a slightly modified Veep14. I'm told the sheer is raised a bit and the stern given a bit of flare but the bottom is per the plans. Waiting for a test:
A Vector builder is keeping a website of the project at http://www.geocities.com/michsand@sbcglobal.net/ but in the meantime I got photos of a Vector completed by Pete Mohylsky in Florida. Here he is fussing with his sail. Hopefully a report soon:
Here is a Musicbox2 I heard about through the grapevine.
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)