The Matinicus Double Ender- Part 21

Fair warning- This is a longish post. I waited much too long to write this stuff up, so there is a lot of material to cover! As always, to start at the beginning, click HERE.

My latest chores on this boat project have been to complete the rudder assembly, including tiller, tiller extension, and rudder blade, plus the daggerboard which I glued up and shaped as well. Way back in Part 13, I detailed the rudder layout, making patterns and mock-ups of the parts, then fabricating the core pieces and assembling all the gudgeons and control line sheaves and what-not. Kick-up rudders are not hard to make, but they must be laid out carefully, and checked for proper operation, at least with paper or mylar patterns. They do have many parts, compared to fixed rudders, but the boat can be beached without removing the rudder, or sailed (at least downwind) in shallow water.

The first thing I had to do on picking the rudder back up, was to cut out the tiller and mortise it through the rudder head. If you remember, this boat has a Norwegian style "push-pull" tiller, to get around the mizzen mast which would otherwise be in the way of a conventional tiller. I found a nice piece of ash for the tiller, made a pattern, then traced it and cut it out.

Tiller pattern.

The tiller itself is mortised through the sides of the rudder. I laid out the mortise, then drilled out most of the waste with a forstner bit. I made a router template and cut the mortise with a top bearing bit from both sides, then trued up the hole with a chisel, being careful to square it up in the process.

The waste is drilled out with a forstner bit from both sides.

Router template.

The mortise is chiseled square and true.

I like to cut the mortise first, then work the tenon on the tiller. Its much easier to fit the tenon to the mortise than the other way around. I actually cut the tenon shoulders with the table saw on the rectangular ash blank before sawing the tiller's curved shape, to make it easy to get square shoulder cuts. Then I sawed the tiller out, and finished up the tenon on the bandsaw and tuned it with a rabbet plane. The tiller is held tight to the rudder with a wedge through the tenon (this is sometimes called a tusk tenon). The mortise has a pitch that matches that of the wedge, which when tightened pulls the shoulders of the tiller's tenon up tight against the rudder.

Sawing out the tenon on the bandsaw. A rabbet plane will tune the fit.

Tiller, tusk tenon, and wedge (made of wenge).

Tiller, tusk tenon, and wedge (made of wenge).

I still had to cut and drive the brass pins that secure the gudgeons and serve as axles for the up and down haul sheaves. I cut these just slightly long, drove them through, then peened over both ends to secure them in place.

Gudgeon pins and sheave axles are driven in and peened.

I like this picture. This is the up-haul sheave.

The next job was to fabricate the tiller extension. This is really just a long push-rod. I decided to make it though, in two parts. One, the basic rod with a universal joint at the tiller end, and two different length extensions to allow some freedom with crew placement fore and aft. I made a long extension to use solo, with the skipper further forward, and a short one to use with the skipper aft, and crew forward. This may or may not prove to be useful, and only time at the helm will tell. But I have the option. To do this, I drilled out the ends of the rod blanks, and epoxied in some threaded air-hose couplings. The two different length extensions have male threads, and the fixed length push-rod has the internal female thread. I drilled these out by hand and eye, but I would have been better off taking more care with a machine setup. The extensions don't sit perfectly, but they are good enough.

Brass hose coupling is epoxied into a hole in the end of the tiller extension.

The male thread is epoxied into each of the two handles.

I used a dremel to clean up squeeze-out on the threads.

All of the extension parts are made from spanish cedar, round or oval in section. I cut these out like a spar, eight-siding, then shaving round. I then fitted the universal joint, scavenged from an old Laser tiller, and glued it into the tiller extension's end. This sits on a pad to elevate the push-rod a little (I think my rudder could have been set higher). At this point, I still need to wrap the tiller extension ends tightly with marline and epoxy the lashing, to help strengthen the couplings. The wood tube wall is kind of thin in those locations.

Tiller extension and long handle are screwed up tight and faired round together.

Tiller extension and short handle.

Mortise for universal joint fitting.

U-joint mounted to pad on tiller.

U-joint mounted to pad on tiller.

Tiller extension with long handle.

With these parts done, I moved on to the rudder blade and daggerboard. I glued up my rough blade blanks (spanish cedar, again) and cut them out as squared rectangles to shape the foil sections. It is better to have the ends square to lay out the foil sections, and any plan-form shaping will be done after shaping the foils. An accurate center line is scribed along all of the edges, and a half-foil template is laid on the line at the foil's end and traced. Note: These foil shapes are my own concoction. I used to loft Naca sections, but now I just draw them out in the computer, based on my required thickness. For these boats, anything close to a foil, and smoothly finished will do.

Computer lofted foils. Dagger and rudder.

The foil shape is marked on the daggerboard's end.

To maintain symmetry, a series of flat facets are laid out equally on each side of the board, and dressed flat with whatever tool will get the job done. In my case, I used a drawknife, spokeshave, slick, big fore plane, block planes, and any other edge tool I thought would help, to avoid the dust created by a big grinder. There is a lot of material to remove, so it is a real workout.

Facets are marked out and planed flat.

Its a workout with hand tools!

To further complicate matters, each foil has to transition to a square section at the top. The daggerboard has to fit the rectangular trunk opening, and the rudder blade has to pivot inside the rudder cheeks. Also, the transition should be coved, rather than abruptly squared, to prevent creating a stress riser.

A gouge is used to carve the transition from foil to square section.

Once the facets are cut, a spokeshave knocks the hard corners off, much like 16-siding a spar. I then use a shop-made, flexible longboard, sanding diagonally first one way then the other across the grain to curve the sections. When it all looks good, and the transitions are done, I get out the random orbit sander with a nice soft pad and some 120 grit discs, and carefully smooth out the foils. I keep the sander moving, and use a light touch. It works very well. With everything right and smooth, I finally cut the plan-form shapes on the blades. The daggerboard tip was cut at the proper angle, and the leading corner was radiused. These edges were then rounded over and sanded into the foil sections.

The sanded daggerboard.

Nice foil.

The rudder was cut out, with a big circle at the top, which rotates inside the rudder core. The bottom was cut, rounded, and shaped just as I did for the daggerboard. I drilled the hole for the pivot bolt, then assembled the rudder to check that everything worked as planned.

Rudder layout, with pivot location.

The sanded rudder blade.

Rudder in the kicked up position.

Rudder down.

That's where we stand now. The dagger and rudder blades will be glassed, with a couple of biaxial layers on their leading edges. The daggerboard will be coated with graphite and epoxy, but the rudder blade will be painted to match the hull. There are still the spars to make, so we have some work ahead of us, but the launch date is approaching. Stay tuned...

The Matinicus Double ender- Part 20

To start at Part 1, go here.

The decks are now finish painted, and all that remains deck-wise, are the mooring cleats and skene chocks. We'll look at those in a later post. 

The finished deck.

The shop has had, unusually, a little down time recently so I decided we might jump on the launching dolly project. I don't usually include the boats in our "make work" for the shop, but I didn't really have a shop specific project I wanted to do. Ashok lost a few days work due to the hurricane, and I didn't want him to lose more, so with both motive and opportunity, we tackled the dolly. 

This is what the launching dolly will look like with the boat on it.

Launching heavier boats at the club presents some problems. We don't have (and don't want) a ramp for trailers because that would drastically alter the purpose and function of our boating program. For the Boston Whaler (our regatta and Safety Boat), we use the neighboring Yacht Club's ramp, but that only happens twice a year, as the whaler lives at the dock from April to November. The Lasers, Sunfish, and 420 use Seitech dollies. These boats are light enough to slide in and out by hand. My crab skiff Cricket, and others like Chris B's melonseed, and Matthew's flat iron skiff, are too heavy to pick up and put on a dolly. So we use modified dollies, custom built to accommodate our boats. These are like a cross between the Seitech models and true road trailers, and use winches or block and tackle to haul the boats from the water. Cricket's dolly uses Seitech wheels and a carpeted bunk cut to shape. It works okay, but the bunks create a lot of friction, and I still have to lift the bow out of the water and onto the bunk, then crank it up. For Mouse, I needed a better solution, so I designed a dolly with keel rollers and a tongue that extends aft past the axle and bunk. 

Cricket's dolly.

The dolly has to be as light as possible, but strong and very stiff. If I had the equipment, it would be quick work to weld the thing up in steel or aluminum, but I am a woodworker, and wood we got, so that's what it will be. I designed the main beam (tongue) as a hollow box beam, using 3/8" multi-ply skins, with either ply or solid wood blocking inside where needed for bolts or structure. The axle/bunk is made in halves, with the aluminum axle rod sandwiched and glued in between. The boat-shaped bunk will be built into the axle structure.

The aluminum axle is sandwiched between two layers of wood.

I bought the keel rollers and winch from an online trailer parts store (of which there are many), and had the parts in hand before building the dolly. One important note: the winch ratchets in both directions, a necessity with rollers, as the boat can easily get away from you when launching! I made a pattern of the underside of the boat the last time it was upside down, to use when laying out the dolly. Mouse, if you remember, has a flat plank keel, like a wherry. It measures a little more than 4" wide on the outside, enough to sit flat without falling over (I hope) as I winch it up the dolly. The keel rollers are about 7 3/4" overall, with about 6" clear in the center. The outside edges are raised up to keep the boat centered. 

The keel roller. The slotted flanges will be cut off so the plates can be bolted to the sides of the beam.

The dolly tongue beam measures 8" wide from just forward of the bunk/axle to the aft end which allows the roller brackets to be mounted to the beam sides, with clearance for the rollers in between. I'll mount the rollers as low as I can get them and still clear the beam. I tapered the tongue from the 8" width at the bunk, to 3" at the handle and winch. There is a framed up solid wood core at the handle end, with an internal diagonal brace to address the load from winching the boat. I cut a tapered, bird's mouth relief into the core to relieve the stress riser created from the blunt ends of the core. The picture should make that detail clear. 

The winch end of the dolly, with its solid wood core...

... and both sides (webs) clamped on.

I did not do this on Cricket's dolly and sure enough, the tongue end snapped right there. I had to add on external braces across the joint, which solved the problem, but I wanted to avoid the issue on this one. I have seen a similar treatment of core plugs inside hollow masts, which is where I got the idea (Ross Lillistone's blog).

The top and bottom skins (flanges) go in between the sides (shear webs), and rest on ply ledgers glued inside, which also serve to bridge the butt joints in the outer skins. These ledgers were glued on first, along with the winch end blocking, then the sides were set up, upside down, and the bottom web was glued and clamped on.

Clamping up the bottom flange (on the top in this photo).

We fit the top web dry, and clamped it all up. When that cured, we flipped it back right side up, and removed the dry fitted top web so that we could organize and fit the rest of the little bulkheads and blocking. 

We flipped the beam right side up to fit internal blocking. The notch for the axle/bunk can be seen here.

Blocking is glued in where needed for keel roller bolts, etc.

With that done, we glued on the top flange. 

The top flange is glued and clamped, closing in the beam.

The structure kind of looks like a DN iceboat hull, and is built similarly. Some catamaran cross beams are built this way, too. In fact, my single outrigger akas were built just like this, except the top and bottom flanges were laminated into a curve before assembling the beams. The beauty of this closed type of beam, over an open "I" beam, is the much increased torsional resistance they exhibit. Probably overkill for this use, but I do enjoy building engineered structures. 

Curved outrigger box beams (akas). Light, stiff, and strong!

I notched the beam to fit over the axle structure, which will also be notched, creating a half lap joint. I won't finish the axle/bunk until I mount the keel rollers. I need this done to figure the correct height for the bunk. That process will be covered next time. 

The Matinicus Double Ender- Part 19

To start at Part 1, go HERE.

Smallish post this time, but progress is fairly steady. I've been varnishing the coaming, oarlock pads, and painting the sheer strake (finally). The coaming finish is straight forward. Getting the light right to see the wet edge is always a challenge, and I ended up putting a light source inside the boat to see if that helps, and it's a toss up as to whether its worth fiddling with it. I intend to finsh varnishing the oarlock pads, coaming, and rub rail before painting the deck, so I'm putting a coat on each night.

The sheer strake has gone through a couple of different ideas, color wise, since the beginning. I thought I would paint it dark blue, and that would look nice, but I got to thinking it was too fussy, so I changed my mind to Hatteras Off White (an Interlux color). I put that on, and couldn't stand it. Next to the gray hull, it looked too yellow. I stopped by West Marine while I was en route between jobsites, and paid their ridiculous price for a new quart of bright white. Jamestown Distributors has the same thing for $10 a quart less!

Anyway, the sheer is done, for now.

The photos don't do it justice, the gray hull with white sheer is quite nice! I saw this scheme in WoodenBoat, on someone's Oughtred Grey Seal, and like its' understated "yachtiness". It's yare for sure. I'll be happy to finally get rid of that pink occume when I paint the deck.

'Til then, then.

The Matinicus double Ender- Part 18

The coamings required some of the trickiest fits yet, short of the frames. The frames were harder, but there was less at stake because they were painted into the boat, whereas the coamings are finished bright. Any misses will be obvious under varnish. Preparation for the decks and coamings began early, and I covered some of this in previous posts. Deck layout was covered in Part 7, and the curved beams and coaming lamination were covered in Part 12. The curved coaming pieces have been hanging up in the shop, waiting for me to get back to them.

A brief description of the concept is in order, though. The curved parts at each end are laminated from 7 layers of 1/16" vertical grain sapele veneer. The two straight parts are re-sawn from a 5/4 v.g. sapele board, to make two sides, and finished to 7/16" to match the curved bits. The joins from curved to straight are half lapped, with a joint length of 2". I did not make patterns for any of it, but marked and cut the pieces straight from the boat. The curved pieces were hung with with clamps, and temp. screwed so that they would return to their exact location after cutting. I was only concerned with the end cuts of each piece at first. I waited until all pieces were fit and joined before cutting any of it to final width, leaving plenty of room for all the pieces to move up or down to tune the joints. 

The curved ends are clamped up and marked for cutting. 

I first decided where I wanted the joins to be, and marked this location on the ends of the curved pieces. I know its fast to make this kind of cut by hand, but I've got a great sliding table saw with all kinds of hold downs only six feet away, so that's how I made the end cuts.

I have a great table saw, might as well use it!

I used a router with a top bearing cutter and scrap mdf for a guide, clamped to the coaming. I hardly ever use this one, but the ancient old vintage Stanley router had the right cutter in the collet already, so I dug it out. This thing is at least 50 or 60 years old, and is fun to look at, plus it works fine. The big wing nut that tightens the motor in the base has never worn out. The D handle Porter Cables all have replacement bolts with nuts because the aluminum wing nuts they come with wear out so quickly. I set the depth a little shy of half way, and tuned the cut with a rabbet plane afterwards. Half way through the center veneer is a handy visual reference for the correct depth of the first half of the joint. These cuts were made fairly quickly, and the coamings hung with temp. screws.

The vintage Stanley. 

The half lap is evident here on the curved end, where it joins to the straight part.

If you look close, you can see the cut is half way through the middle veneer layer.

I next clamped one of the straight parts in the boat, and roughly marked out the sheer curve and length (left a couple of inches long). At this point, I just wanted plenty of width to work with, so they appear quite high in the pictures.

The straight pieces are clamped in, to determine their length.

This shows the amount of sheer curve there is to cut.

I figured out the correct angle of the end cut on these straight pieces, and made the half lap in one end, checking the fit of the joint on the boat. The first one's easy. The trick is getting the exact length of the piece figured out, to make the joint at the other end. The piece won't fit until every little bit of curve is clamped into the coaming, and there it gets too short real fast. What I did was transfer a reference mark from the deck to the outside of the coaming piece. I then took a thin scrap of ply and butted it to the join at the other end (with the correct angle cut on the end of this stick), bent it tightly around the carlin, and marked the reference on the ply. I lined up the reference mark from the ply piece to the actual coaming, and marked the end cut (at the proper angle), but I also added 1/8" to the length, hedging my bets. I cut that half lap, and hung the coaming back in the boat. It came out longer than the extra 1/8", but it was fairly easy to mark the correct length the second time, and re-cut the joint. The piece won't fit, as I said before, until every bit of the curve is in the piece. I used a mallet and a block to drive the first end tightly in place, and finally was able to snap the section in. I ended up fussing and tuning these joints quite a bit before I was finally satisfied, though on the next one I was more cavalier in my approach. I will admit to needing a tiny shim on the outboard port side aft, but its matched well, and is not noticeable at all.

The half lap fits well. The top and bottom cuts will bring everything to a fair line.

 With the joints all fitted, I marked out the top and bottom cuts around the entire perimeter of the coaming. I made up a gauge block to find the bottom edge, since this was a constant height below the deck. This block has a slot to fit over the coaming, a leg that rides on the deck, and a longer leg that hangs done inside the boat. By running this block all around the boat, the lower edge is marked. I also put a screw reference mark on the jig, to keep the screw heights consistent (the fore and aft spacing of the screws was already marked out).

A simple height gauge block to mark the bottom edge of the coaming.

The gauge in use. Note the tick mark for screw heights.

The top cut was marked with a simpler gauge block that just rode around the deck. I cut the coaming 3/4" above the deck, no higher than the oarlock pads so as not to interfere with the oars. In the curved ends, I sprung in a little more height to give the deck more shape. The transition is tricky, and I did the best I could. Its not perfect, but it looks pretty good.

I then had to pull everything back out of the boat, and cut the top and bottom lines on the four pieces of coaming. I also rounded over all the edges, except right at the half laps, where there would be some final fairing to do after glueing it all in place. One trick I've learned when bonding bright finished pieces with epoxy, is to pre-sand and seal everything with a coat of shellac. This keeps epoxy off of the wood, and out of the grain, making for a much cleaner installation. I tape off the areas to be bonded of course, before shellacking. I mix my own shellac fresh, using amber flakes and Bekhol, and use about a 2 lb. cut for sealing.

The finished coaming parts get a coat of shellac.

After shellacking, I pulled off the tape, and reapplied it to mask off the areas around around the glue joint. I also masked off the deck, to keep that as clean as possible, and papered the boat interior as well. I'm a stickler for keeping epoxy off the boat. It pays off in spades down the road. Two of us glued up all the pieces of the coaming in one go. Help was nearly mandatory for this job, springing in and driving all the gluey parts home, then cleaning up the squeeze out. It took us 2-1/2 hours, start to finish. After curing, I faired all the transitions, and that's where we are now. I'm very happy with the grain match between the laminated veneers and the solid sapele stock. 

All four parts were glued on in one go.

The transitions at the laps were faired and sanded.

Except for bunging and varnishing, the coamings are done!

I still need to bung all the fastener holes, and re-seal the sanded bits and trimmed off bungs before varnishing. I may go ahead and paint the deck next. We're getting closer!

Stay tuned...