The design is “Cerlew” which is one of the designs shown in Edwin Monk’s recently reprinted 16 small boat designs from Edwin Monk. The design is from 1934.
I made several changes from the original drawings.
1. The hull planking is 10mm okoume marine plywood instead of 9/16 pine or 5/8 cedar planking shown on the drawings.
2. I used a completely different centerboard design. In Reuel Parker's Sharpie book, he uses the 19' sharpie “Black Skimmer” as a construction demonstrator. He describes Black Skimmer’s centerboard as the most effective centerboard he has seen. The centerboard shown for that design was the basis for the new centerboard. I used a 1˝ “ thick foil section constructed per Reuel Parker’s book.
3. I designed a modern profile kick up rudder that matches the centerboard. I used Schaefer medium duty pintles and gudgeons.
4. I installed a Tecumseh OHH50 5 hp, 4 stroke, OHV engine that just fits under the rear seat. I checked with Tecumseh engineering and the crankshaft will handle the thrust load from the prop. For the engine bed, I epoxied a flat-topped wooden wedge to the hull bottom. It was cut to the proper angle for the drive shaft and the engine is through-bolted to the hull. The flat-head SS bolt heads are buried under the outside layer of fiberglass cloth. Cerlew has a skeg so I was able to bury the prop in the skeg. Billings Diesel and Marine made a complete propeller (6X4) and drive shaft assembly that work beautifully though it wasn't cheap. The engine is direct-drive with a pull starter. A few pumps of the primer, pull the starter and you are off. It goes 4˝ knots in idle and 5˝ to 6 knots at full throttle. The boat manages to have a protected propeller and still only draws 10" of water. It’s limited by hull speed and will not plane under power. With 5 HP, the engine does not have to work hard; I usually cruise with approximately half throttle.
5. I made a folding mast assembly. For the lower, fixed, square section that goes through the deck to the keel, I used simple flat steel side plates with a hinge bolt. The round upper mast section uses 3" steel pipe cut and hammered into wrap around straps that are through bolted to the butt end of the mast. Combined with a quick release fitting on the forward stay, the mast goes up or down quickly and easily.
6. Because the hull ribs vary from 2” to 2 1/2" depth, I put 2" Styrofoam in between the hull bottom and the floorboards for buoyancy.
7. I put a dingy bailer in which works under sail or power.
8. I added a rowing seat with 2 wood dowels on it’s bottom surface that mate to holes in the top of the centerboard case that allows very quick set up for rowing. The forward end of the boom can be raised up on the sail track and the aft end set in its crutch to allow headroom for rowing.
New Jersey sail maker Moorehouse Sails made sails for me per the plans and they seem to work very well.
With 2 people I've seen 9 knots. With 4 people it sits lower in the water and feels much heavier but still I’ve seen 7 knots. It likes to be upright. If it heels over too much it kind of mushes and slows down.
I used mostly Race Lite fittings.
The only change I would consider would be to build a hollow wooden mast instead of the solid clear Douglas fir I used. It may not be worth the extra effort.