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by Doug Cameron - Sewanee, Tennessee - USA

Graham Byrnes is an experienced mariner, circumnavigator, and naval architect who has been featured in WoodenBoat and Small Craft Advisor magazines.  His super-efficient power boat, Marissa, won the first WoodenBoat design challenge. His other designs, from catamarans and small skiffs to comfortable trailer sailors and powerboats can be found at:

His Core Sound series of planing centerboard cat ketches have proved very successful in longer races.  The Core Sound 17 won the North Carolina Maritime Museum's 65 mile Great Race twice, only to be beaten by the 20.  The17 and the 20, along with their supercharged sibling the EC 22, have each won the WaterTribe Everglades Challenge, and the 20 and EC 22 have won the 100 mile North Carolina Challenge. This year the 20 won the new 300 mile Blackbeard Challenge in very challenging conditions.

Byrnes has sold hundreds of sets of plans for the 17, 20, and 22 to homebuilders, and he is now producing pre-cut kits for the 17.  The 20 Mark I is very fast, but it is wet to weather and there is no place to sleep out of the weather.  I put a dodger on my Mark I, and Paul and Alan Stewart had improvised a cabin on theirs.  Graham designed a Mark II for a customer, adding a small cabin and water ballast.

I got involved because I had built a Core Sound 20 from plans and was interested in the Mark II design because the small cabin provides a sheltered place to sleep and protection from spray when beating into chop.  But Graham's mind was working faster than mine.  He already had a Mark III on the drawing board and planned to sell it as a kit.  The new model was designed as a whole rather than added onto the previous model.  It would be self-righting with a self-bailing cockpit, water ballast, the cabin, and the mizzen moved aft to make it easier to row from the bridge deck.  In fact, the angled seat backs provided storage for the oars.

Graham needed a guinea pig to and build kit #1.  I volunteered.  Graham values quality and wanted to be sure everything fit together properly before he sold a kit (several were already on order for both the 20 and 17), so I came to his shop to work with him to assemble hull #1. 

Graham cut the boat on his CNC machine (saving me a couple of months in my shop and giving Graham a way to test the tool pathing for subsequent kits). I arrived at his shop on the shores of Pamlico Sound just after Thanksgiving in 2013. Camping out in a 40 foot catamaran under construction, I went right to work. I spent about 18 days working in Graham's shop before she was ready to be trailered back to my shop in Tennessee.   

From her arrival in my shop in mid-January, 2014, I worked mostly full time for the next three and a half months, with the exception of the couple of weeks it took to race the old Core Sound 20 in the Everglades Challenge.

By early May I took her to an excellent canvas shop (Island Nautical - formerly JSI) in Florida for the cockpit cover and to the Cedar Key Small Boat Meet.  I had decided to put the cabin cover on jib sheet tracks with batten cars so that I could slide it forward for access to the main mast and anchoring from the protection of the cabin.  (Later builders would decide to build conventional sliding hatches with a forward hatch for access.)

Then I had to let her rest while I did my summer job (teaching whitewater canoeing and kayaking at a North Carolina summer camp), went camping with my wife for a month in Nova Scotia, and helped with the WaterTribe Blackbeard Challenge (won by Alan and Paul Stewart in their modified Core Sound 20).

In October, I was back home  and in the shop to do the finish work.  She was complete enough by the last weekend in October to take her  to Graham's B&B Messabout in North Carolina, where Graham got the opportunity to sail her hard and to see if she was really self-righting (she was!).  Now that all those little details are done, I look forward to introducing her to the WaterTribe for the 2015 Everglades Challenge in March.

Graham at the computer that controls the Shop Bot
The scarf finger joints
One side of the bottom with the forward part stitched together
Going 3D
Graham and Alan Stewart fitting the forward bulkhead in
Alan installing baffles for the water ballast
External stand that will be part of the kit
Offset centerboard trunk installed
On the trailer ready to be moved to Tennessee
Seats installed
Seats for the cabin with reinforcing rings
Details os stringers and seat backs
Clamping up seat backs and hatch drain channels
Cabin interior progress
Cabin top ready for installation
Looking forward into cabin
Looking aft in the cabin
Flipping the boat
Hull flipped for glassing and painting
Openings for Andersen bailer, fill plug, and centerboard
Bushings for attaching mast sections
Rudder body
Bottom painted
Drilling the centrboard pivot hole
Track and sliders for the cabin cover
Completed cabin cover
Tabernacle and mast crutch (in mizzen socket)
Rub strake installed and varnished
Gimballed stove and tube for oar end
Cabin painted and varnished
Bow light

YouTube videos:

Going 3D:

Sea Trials at the B&B Messabout:

Self righting test:

Sailing the completed boat:

The whole story of my construction is at

Alan Stewart, Graham’s apprentice, had a series of very instructive videos about the construction of a Core Sound 15 at:

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