Deer Isle Koster Boat

Bruce Elfstrom

The double-ended jolles of Denmark and koster boats of Sweden inspired the hull form of the glued-lapstrake plywood Deer Isle Koster Boat, designed by Bruce Elfstrom to be a safe and enticing daysailer for his daughters on Deer Isle, Maine.

Norwegian faerings, those centuries-old, slender, four-oared fishing boats that are fast under oars and surprisingly nimble under sail, have provided a wealth of inspiration for numerous modern small-craft designers. Built lightly using plywood glued-lapstrake construction, designs based on the historical type have proved to be excellent trailerable daysailers that sail well and handle beautifully under oars. They are also beautiful to look at. But there’s no reason why translating the Scandinavian inspiration should stop with faerings.

I think Bruce Elfstrom of East Haddam, Connecticut, is on to something when he looks to the jolles of Denmark (see MARCUS NOER, from Small Boats Annual 2009) and double-enders, such as the koster type from Sweden, for more ideas about how workboat types with generations of success behind them can be reinterpreted for modern uses and construction techniques. This branch of the family may well go on to its own phenomenal success.

Elfstrom is a novice as a designer, but his affair with wooden boats started long ago on Deer Isle, Maine, where his family has long had a summer place. Half Norwegian and half Swedish, he grew up mostly on Deer Isle after running there at the age of 15 to find peace after having lived for four years in Beirut, Lebanon, where his mother worked first as a journalist and later as a United Nations diplomat during that country’s civil war.

Boats became an integral part of the life that Elfstrom found on Deer Isle. Later, he went on to restore a 34′ cutter, and he found himself believing in the process enough to found the Wooden Boat Rescue Foundation, which puts endangered old boats in the hands of those hoping to save them.

Adventure, too, has been part of Elfstrom’s life—he runs a company that leads advanced four-wheel-drive backcountry adventure treks in places like Mongolia, Labrador, and Iceland, and trains drivers (among them Navy Seals) in the finer arts of handling vehicles in rough terrain. So he took notice when “Raids”—a new type of small-craft event involving weeklong series of races for self-contained sail-and-oars boats along scenic coastlines or through archipelagoes—started in Europe (see WoodenBoat No. 187).

He recognized the potential instantly. He has been a regular at the annual Small Reach Regatta in Maine, and soon he was designing his own faering-inspired boats, seeking a fusion of new and old technologies. The first was the NorseWater 19. The second was Raider 18, a slender, glued-lapstrake plywood boat outfitted for trekking.

Tom Jackson

Watertight compartments under the sternsheets not only provide flotation with the hatches locked shut but also provide dry stowage when camp-cruising.

But back at the family place, his daughters, Petra, 14, and Oaklea, 12, began to put Elfstrom in mind of something other than an on-the-edge raceboat that would be safe and yet fun for them. Once again, he found a gap between the performance he wanted and the appearance of the boats he found available, and once again he looked to Scandinavia to find a bridge between function and form.

“I love them,” he said of the boats of that region. “They’re just in my blood. I’ve always loved the stern of a double-ender.

“They outgrew their Optimist dinghies real quick,” Elfstrom said of his daughters. “Oaklea, at 5′10″—you should have seen her in an Opti. She was like a spider in a jar. She didn’t get that she’s grown, like, 3′.”

Designing and Building the Deer Isle Koster Boat

For what became known as the Deer Isle Koster Boat, Elfstrom had in mind a hull form that would be safe and stable and a rig that would be simple and provide an adequate but safe amount of power.

This boat, he thought, needed to be something that the girls would find enjoyable for daysailing, captivating for adventuring as they gained confidence, and attractive enough to keep them interested for many years to come. If they find themselves more daring as they gain years and experience, perhaps the rig could be expanded later.

The resulting boat has a bit of everything in its lineage. “It’s like that Raider boat fused with a jolle, a koster, with a bit of Beetle Cat mixed in,” Elfstrom said. That’s a faering, a beamy double-ender, a large coasting double-ender, and a small New England catboat. At 14′ long, the resulting fusion has an ample beam of 6′, but draws only 5″ with the centerboard up, and about 4′ with the centerboard down.

Tom Jackson

A broad and burdensome hull can still have shallow draft, and the koster boat is readily put ashore.

Too committed to his own business to take the time to build them himself, he ordered a pair from builder Eric Friberg of Bellingham, Washington, whose work he had seen in the WoodenBoat Launchings section, and the test sails came in August 2010. “The underwater profile is more along the lines of a racing dinghy,” Elfstrom said. “It’s kind of a planing hull,” and in its second outing, the boat comfortably made more than 7 knots with the breeze steady at 15 knots and gusting to 20.

The boat has a long foredeck, short afterdeck, and modest sidedecks, with a low-profile coaming. The mast is stepped through the foredeck, which keeps the construction simple. Below the foredeck, a bulkhead with a fitted hatch is installed forward of the mast to provide ample dry storage and built-in flotation. More flotation chambers are situated aft and to the sides below the sternsheets and side seats, doubling as additional dry storage accessed through gasketed hatches.

Tom Jackson

The shaped bronze-rod mainsheet traveler has the distinctive curvature used in Danish jolles.

Some details, notably the high oarlock pads and the curvaceous bronze-rod horse traveler, are taken directly from the jolle type of Denmark. The boat has no exterior keel, instead being strengthened by an inner keelson, but it has a short skeg. The centerboard and rudder are both weighted and will kick up should the boat ground out. With her shallow draft, the boat beaches easily and at about 350 lbs all-up, she’ll be comparatively easy to manhandle up the shore if need be. Elfstrom designed the floorboards to remove and fit between the seats to make a large sleeping platform for adventure cruising.

The rig is not Scandinavian—it’s a balance-lug with a small jib. It’s easy to handle, easy to reef, easy to strike, and easy to stow. The jib is set on a small roller-furler, making it easy to strike from the cockpit. The lug yard hoists on a leathered bronze ring with a hook welded to it. All of the rigging gear is simple. The masts require no stays, so if the boat were trailered it would be quick to set up at the boat ramp ahead of launching or afloat afterward. The hull has no ballast, relying instead on its great beam, crew weight to weather, and conservative sail area to keep her on her feet.

I sailed with Elfstrom—and neither of us is as lithe as a 14-year-old girl—and found the boat stable and responsive in conditions ranging from light air to puffs of up to 10 knots or so. She remained steady as we shifted crew weight, which speaks well of her stability. The boat came about handily and seemed weatherly and responsive. Elfstrom says that he can walk on the foredeck without danger of destabilizing the boat, and the cockpit is uncommonly roomy and comfortable for a 14-footer, giving the sense of being in a much larger boat.

Tom Jackson

A kick-up rudder makes easy work of venturing into shallows.

Elfstrom considers the two boats he had built for his daughters to be prototypes. The planking lines are still being finalized: One boat is built with nine planks per side, the other ten. Some pieces, such as belaying pins and the lines, he selected because they were off-the-shelf and time was running short for the season. The tillers ended up too short. The hulls are built with 6mm okoume plywood covered with Dynel set in epoxy, and they are decked with 3⁄8″ meranti plywood.

Some elements of the initial design and construction were chosen deliberately to keep costs under control. Elfstrom intends to revise and perfect these details— together with finalizing the placement of such things as cam cleats. He and boatbuilder Clint Chase of Portland, Maine, are working to finalize plans and they hope by early 2011 to develop a prototype kit, something that Chase has been doing with his own designs. An experienced builder working from lines could make his own judgments about such things as lining off for planking—which is critical to get right in a boat of this type—or deciding the proportions of the coaming, but a novice might be well advised to await the promise of a kit.

As for the boats themselves, however, their worth is already being proven by Elfstrom’s daughters. “I wanted them to have a big deck to jump off of, climb up on, swim off of—to go out and just Swallows and Amazons stuff,” he said. The side decks are wide enough to sit on, the coaming low enough so it doesn’t interfere with the comfort of sitting that way or hiking out when need be. The cockpit side seats are comfortable, too, and wide enough to grow into—“They can use this boat when they’re 40.”

Deer Isle Koster Particulars

LOA:  13′ 10″
LWL:  12′ 6″
Beam:  5′ 10″
Draft:
–board up:  6″
–board down 3′ 8″
Weight:  330 lbs
Sail area:  121 sq ft
–main: 101 sq ft
–jib:  20 sq ft

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Bruce Elfstrom, 112 Hemlock Valley Rd., East Haddam, CT 06423; 860–873–2169, [email protected]; www.overlandexperts.com. Direct questions about plans or kits to Chase Small Craft, 959 Portland Road, Saco, ME, 04072; 207-602-9587.

Bruce Elfstrom

The koster boat’s designer, Bruce Elfstrom, an amateur with an eye for small-craft design, describes the design as a fusion of Swedish koster boats, Danish jolles, and modern lightweight “Raid” boats, “with a little Beetle cat thrown in.” Some details have been altered—for example, the rudder profile has changed from the one shown in the rendering.

Bruce Elfstrom

Elfstrom worked up his lines in DELFTship software after sketching profiles freehand. (Atypically, these body sections are shown full-width, with forward sections on the left and after sections on the right.)

Check Out These Other Faering Designs

The faerings of western Scandinavia have inspired designs from the likes of Clint Chase, Iain Oughtred, and Joel White. If you like the look of these handsome double-enders, here are a few other articles you might enjoy, including a boat built by one of our readers.

Elfyn: Iain Oughtred’s other faering

Drake: A faering for today’s oarsman

IRONBLOOD: Reader-built boat

Is there a boat you’d like to know more about? Have you built one that you think other Small Boats Magazine readers would enjoy? Please email us!