Sunday, April 12, 2015

Point Comfort 23- Part 2

The strong back was next, and for this four by twenty four foot structure, we used fir 2 x 8’s. We picked out the best construction grade stock we could find, and jointed one edge of each, then ripped them to a common width.

Jointing an edge of the 2x8's.

Deciding which piece goes where, based on straightness and flatness.

We set up and screwed together the strong back, again squaring the assembly carefully. We then braced the strong back to the trestles with plenty of diagonal bracing so the whole business is rigid, then cut notches in the center of all cross pieces, through which we stretched a taut center string line. this will be used to line up the molds.

Cutting the center line notches. Bracing can be seen here.

Stretch it tight!
We chose particle board for the molds (I hate MDF dust), and I had one team laying out stations from the full-size patterns, and another team cutting the molds with our home-made track saw. This is a chine hull, so all the cuts are straight lines.

Howie and Javier lay out the molds from full size patterns.

Pat Daniels runs the home made track saw.

Hans has taken over here. There were a lot of cuts!

John and Severn are setting up the cross ties.
The layout team was careful to mark the vertical center-line and waterline on both sides of each mold. Even with plenty of help, the molds were an all day project. The next day, we set all the molds up, using a laser to get the waterlines all in the right place, and a four foot level to get them plumb.

Midship mold goes in first.

I don't know what that old man is saying.
I always set up the midship mold first, spending the time to get it right and braced securely. We screwed 2 x 2’s across the strong back on the stations, then shimmed the molds to the laser and screwed them to the cross spalls.

The mold center line aligns with the string line on the strongback, and a laser is set to the comm DWL height.

The molds are braced securely!

Pat, Jim, and Hans.

Each subsequent mold was braced back to the midship mold, and held the correct distance apart, 36” in this case. When the molds were set up, we couldn't resist springing a batten around the sheer and chine, to get a sense of the hull shape.

That’s where we are now. We have to cut out the stem, and fabricate the transom next, before setting up the permanent longitudinals. Stay tuned!

Saturday, March 28, 2015

New Boat Project- The Point Comfort 23

The new molds! Thanks to Howie for this photo.

We could have chosen most anything as our inaugural project, but we’ve been talking about a bigger, better looking, more seaworthy boat to replace the thirteen foot Boston Whaler that we use as our race committee, sail instruction, and general yard boat. We need to be able to function safely in conditions that push the limits of the little whaler. That boat loves to gulp seawater over the bow. We looked at a lot of designs, including the nineteen foot semi dory from John Gardner, Carolina Skiff types, the Bateau Boats FS17, the Handy Billy 21, and finally the Point Comfort 23 from Doug Hylan. One important aspect of this building project will be to teach woodworking and boat building skills, and the use of hand and power tools to a group of interested people, some of whom have never seen a significant boat materialize from the ground up. We could have chosen a boat design that offered a CNC kit, but honestly, there’s not much to learn from a bunch of puzzle joints and fifteen gallons of epoxy. The Handy Billy was extremely appealing as an antidote to the kit boat route, but we felt like she wouldn’t offer us enough initial stability, good sea boat that she is. We need a stable platform and lowish topsides from which to work. I had looked before at the Point Comfort 18, but pretty as she is, she’s not enough boat for us. Then Doug Hylan introduced the 23, and we had found our project.

 It’s a simple, rugged, quite pretty outboard derivation of a classic Chesapeake deadrise skiff. She’s got the straight stem and deep, narrow forefoot of the type, but designed for plywood construction over more or less typical longitudinals. The hull is heavily built from 3/4” meranti ply. The forefoot is cold molded from two layers of 3/8” ply with vertical seams staggered. Besides the chine timbers, clamps, and keelson, there is very little internal framing, other than floors, bulkheads, and deck beams. The heavy skin makes this possible. This boat has twice the displacement of the 18, and maybe four times the dry weight. She’s substantially built, to be sure.

A  meeting was held to choose the boat design for our new project.
We held a meeting at the club before Christmas, open to anyone interested in the project. I was gratified to fill the room with interested folks. I’ll admit to putting a little spin on the presentation, having already decided that I liked the PC23, but the idea was taken up with real enthusiasm. Doug Hylan has designed and built quite a few mid-size to large power boats, and I trust his eye and his design skills. I took the idea to our board of directors, with a preliminary budget, and was given the green light to proceed! Which is a good thing, because I had already bought the plans.

Our group met again to review the construction process.
The first task in this project was to build a suitable strong back, which can be interesting on a very out of level dirt floor. I wanted to devise a system that would be rugged, but that would not be in the way when not actually building a boat, and which could be set up and adapted for any other boat. We went to concrete footings again, laying out three pairs of footings, about nine feet apart, put carefully in line and squared to each other. We dug holes and built 12” square forms which we lined up with a laser and strings, then poured the concrete.

Laying out footings for the strong back.

The forms were laid out with a laser and string lines...

And the concrete was poured.

After curing, we drilled out the concrete for threaded inserts (again with the laser for set up) which we epoxied in. This was done in sub-freezing temperatures, so we warmed the inserts in a pan on the wood stove, and set up light bulbs on the concrete, which kept everything warm overnight for a good epoxy cure.

Threaded insert with bolt.

Threaded inserts were epoxied into the concrete.

Locally applied heat cured the epoxy.
Next we bolted in some 4 x 4 clips like we used on the bench legs, again checking the alignment with a laser.

4x4 clips are aligned with the laser...

... and bolted down.
We then switched the laser to give us a horizontal benchmark, measuring the relative heights of each location, then cutting six legs to support 4 x 4 trestles, all at the same height. I like to take care at each step to insure a level and square set up, because it makes the final shimming of molds much easier. The trestle legs are all marked for their individual locations. We can remove them, and their clips, and just put the bolts in for an unobtrusive set up when not in use. For a smaller boat, we might use only two of the trestles.

Chris drills clearance holes in the trestle legs for the bolt heads.

The trestles were all custom cut to a common level benchmark.

And here they are. A level base to build our strong back on.
 Next time, we'll look at the strong back and molds. Thanks for looking in.