A builder who’s wedded to wood
Posted on 01 October 2010
Written by Eric Sorensen
Page 2 of 2
The makings of a Pulsifer
When I visited Dick at his workshop, I got a clear picture of just what goes into making a quality wooden powerboat, and I want to share that view with you here. Although you may not be familiar with some of the more esoteric lingo, just a glimpse at the building process will show you a tradition that reaches far back in time, a tradition I, for one, value immensely.
All of the wood that goes into a Pulsifer Hampton - white pine, cherry, cedar, and red and white oak - is local, and a good bit of it comes from Dick's 25-acre property on the water. The stem, knee, keel, deadwood, horn timber and sternpost are all of good-quality red oak. Dick likes it because it's porous and soaks up wood preservative like a sponge. He built a boat with a white oak stem a few boats ago, but the wood was a real bear to work with - hard and gnarly.
Dick knows wood better than most people, of course. "Cedar is very stable with varying moisture content. Pine is fine, but it dries up more," he says. "As soon as the weather permits, we leave all the doors open in the shed so the wood doesn't dry out. All the wood is air dried on sticks for a couple of years. Cedar doesn't need to be dried for very long, but pine does."
Dick also knows how to run an efficient operation. He builds six stern sections (transoms) at one time to get some economy of scale. The transom has a piece of cherry across the bottom and oak across the top and on the sides - all steam-bent to shape. He also planes and strips a lot of pine - for 18 months worth of boats. "So we make a big mess only once in a while," he explains.
The strip planks are ripped from clear, knot-free pine boards to ensure that the planks will curve reliably. This is important because the strip planks initially serve as battens, as we'll see. All the wood is cut and air dried before use. "We get the wood winter cut when the sap is out of it," says Dick. "It's already partially seasoned when it's cut. Half of the weight of hardwood is the moisture."
As is typical of building wooden boats, the backbone is bolted together, temporary molds are set up, the transom is built and braced in position, and then the planking goes on. Dick has a piece of plywood that's marked for the location of the keel bolts, molds, floor timbers and frame pockets (the notches in the keel that the ribs mate into). He starts with the stern, keel and deadwood, which are made from 3-1/2-inch oak. The building process then involves work on the sternpost and horn timber, which are made from 4-1/4-inch oak to give them more strength, and the rudder post that goes through the horn timber. Once the keel is bolted together, he cuts a rabbet to receive the planking, manually cutting it from the sternpost forward to the stem.
Next, he starts fitting the knee to the stem, the horn timber to the sternpost, and the sternpost to the keel. He shapes the deadwood to improve water flow to the prop and rudder, and he beds (bonds) it all together with 3M 5200 death-grip adhesive. There are five half-inch keel bolts in the deadwood, two in the stem and two more in the keel for the knee. All are back-bored and bunged. There's also a pine stopwater between the stem and the keel.
The oak members do not swell very much, unlike pine. So he takes a 3/8-inch block of pine, planes it into an eight-sided plug, sands it smooth and round, and then drives it through a heavy mandrel to make it a cylinder. This gets dipped in pine tar and driven through the 3/8-inch hole where the knee, stem and keel join together. When the boat is in the water, the pine swells up in the hole, creating a watertight joint.
Once the boat's backbone is assembled, Dick sets it up on the building stock, or foundation, on the shop floor. The horn timber is fixed in place, the stem set vertical (using a 4-foot level) and braced to the overhead, and then the sternpost is set vertical and braced. Next, he fastens the stern section to the horn timber, making sure it is level side-to-side and that it's even fore and aft, using a tape measuring forward to the bow nail.
With the keel, horn timber, stem and stern in place, the No. 1 mold (a temporary form shaped like the hull in section) goes in. It is fastened to the keel and to the ceiling of the shed; the No. 2 and No. 3 molds go in later. Dick uses little molds initially that allow him to strip plank out a foot or so from the keel, while making it easy to get in and out of the hull as he's building it.
"Then you start stripping," he says, referring to the planking process that starts up around the turn of the bilge, which is the first waypoint. Each strip is beveled on the bottom while it's still on the bench to conform to the edge angle of the last strip. Then he comes up around the turn of the bilge and goes out 12 strips away from the keel.
At this point, Dick sets up the big molds because he doesn't need to be climbing in and out of the hull anymore. The strip planks are edge-nailed to each other with silicon bronze ring nails (ring nails hold pretty much like screws), and at every fourth or fifth plank they are also nailed to the ribs and floor timbers.
"At the turn of the bilge we nail every two or three planks, since the bend is tighter and the wood is stressed more," Dick says. The nails are bent over or clinched on the inside.
Once the hull is planked far enough out from the keel, the oak floor timbers go in. They are fastened with 2-inch-long by No. 14 silicon bronze screws and 3M 5200 adhesive. Once the planking is up to within a foot or so of the sheer, he puts a sheer batten on to mark out a fair curve. He then continues planking right up to the sheer, adjusting the width of the pine strips so the last one meets the sheer evenly. Dick then removes the molds, except mold No. 1, which is used to hold the hull's shape until the deck is framed.
He sands the interior of the hull and nails the steam-bent oak ribs in place. The ribs follow the curvature of the planking and are 1-1/2-inch by 3/4-inch good-quality oak that is straight-grained and clear, with no knots. As with the strip planks, this is important so that they will bend fairly around the molds; a knot would put a crease in the bend. Once the planking is completed, the sheer clamp goes in and is molded to follow the shape of the hull at the gunwale.
In addition, the process requires the mechanical installations in the bilge, including the shaft log, and putting in the big deck beams, the knees in each corner, the side deck beams and the side deck. The deck beams go in forward, with the king plank notched into them, and next comes framing the foredeck and stern deck followed by the king plank and side deck planking. A knee in the midships area under the coaming is used to stiffen the side deck. There is more to it than that, but you get the idea.
"Before the cockpit sole goes in, we start filling and finishing the hull," Dick says. "The decks and washboards go in with countersunk screws, and there's lots of bunging to do with the cedar and pine. We fill all the holes on the outside of the hull and fair it up. We take half a day to Bondo - it's actually Evercoat lightweight autobody filler; we call it Hampton in a can - and another half a day to sand. Then we grind the outside of the hull with 24- and 36-grit paper to fair everything up, which gets rid of the excess Bondo and high spots. Then the secret process of raising the grain occurs."
The "secret process" Dick is referring to involves spraying the hull and decks with 5 gallons of hot water to "relieve" the grain. The water raises the grain back up to where it was originally if it was compressed by a hammer or clamp. Then Dick sands again with 40- and 80-grit paper. There's a lot of sanding involved in building a wooden boat.
Still to come is the application of four coats of primer thinned with Penetrol and turpentine, installing the rubrails, the engine beds, the oak spray rails, and so much more, including the cockpit sole. The sole is made of pine boards 18 inches wide, with edge boards screwed directly to the floor timbers. The other ones are screwed down with exposed heads so you can get them up, and then there are large hatches for bilge access as well. Finally, the console and running lights go in.
Dick uses several coats of Epifanes Oyster White 24 oil-based enamel as a finish coat on his boats. He says the bottom gets Hydrocoat Pettit, which is water-based so it won't "stink up the shop."
Tender loving care
Like most wooden boats, Pulsifer Hamptons will last for decades if they are taken care of. "The first boat I built in 1973, called Walrus, is still in good shape," Dick says. "If they're in salt water and reasonably well looked after, which means keeping them salted, they will last and last. It's the freshwater boats that are a worry or the boats that just sit. Boats rot from the top down."
"Salted" means keeping a layer of salt on the boat while it's in use during the season, with the salt acting as a preservative. "Keep the boat salted," says Dick. "Use a 5-gallon bucket full of salt water to wash the boat off, not a freshwater hose."
Preventing rot is a key reason why Dick doesn't glue the strip planks. Not gluing allows the salt water to wick up the hull between the plank seams, while the adhesive would act as a moisture barrier. He says it's critical to allow lots of air circulation in wooden boats, which is why there's a triangular hole in the top of the bow spray dodger that acts as a chimney. The venturi vent back on the stern deck also helps pull air through. The cedar deck hatches have beveled edges and gaps, so there is plenty of space for air to circulate.
The bilge coating is a recipe that Hamilton Marine calls "schooner deck finish" because it's used on the decks of schooners in Penobscot Bay. It's a mix of pine tar, turpentine, linseed oil and a little Japanese dryer. You buy the ingredients and mix it according to the recipe. Dick lathers it on as he builds a boat, an open pot always at the ready. A final coat of wood preservative goes on right before the deck goes down. The wood preservative goes right through the schooner deck finish.
The Pulsifer's deck is right at the waterline, so water drains directly into the bilge, which means the bilge pump has to pump the water overboard. The outer sections of the deck are screwed and bunged in place, but a series of hatches in the middle of the deck and around the engine box give good bilge access. Ventilation is provided by air gaps around the deck perimeter, as well as the vents and hatches, as previously mentioned. The aft deck is made up of wide, tapered cedar boards that are sledgehammered into place, so the deck itself is as tight as a drum once completed.
If you're wondering how much work it takes to maintain a wooden boat such as a Pulsifer Hampton, it is interesting to note that Dick maintains 50 of the 107 boats built to date. He refinishes the boats and then brings them to the storage shed for the winter so they're ready to launch in the spring. The fall treatment usually consists of a fresh coat of paint on the hull bottom and topsides, and a clear Armada alkyd coating on the side decks, interior and transom, producing a natural wood finish.
For wooden-boat lovers, Pulsifer Hamptons are great little 22-footers easily pushed along by a fuel-sipping diesel, so if they take a little more work to maintain than a fiberglass boat of the same size, that's OK. They'll last a long time, given proper care, and they're versatile, enabling owners to use them as workboats or as a boat the family will enjoy. Perhaps most important of all, they're beautiful creations built in a traditional way. And did I forget to mention that the boat is also perfect for teaching your kids about life on the water? Last I knew, Dick does not offer iPod connections or flat-panel televisions on his boats, so your kids will be away from the video games and loud music for at least a few hours at a time.
For information, contact Dick at (207) 725-5457 or visit www.pulsiferhampton.com.
Eric Sorensen is a consultant to boat- and shipbuilders and to the government. He was founding director of the J.D. Power and Associates marine practice and is the author of "Sorensen's Guide to Powerboats: How to Evaluate Design, Construction and Performance." A longtime licensed captain, he can be reached at eric@sorensens guide.com.
This article originally appeared in the October 2010 issue.