B&B
Yacht
Designs
Ocracoke 20
The Ocracoke 20 is a family member of the distinctive Carolina Sportsfisherman style of boats which this office designs for several of the local North Carolina builders. It has all the sexy appeal and performance of those boats, but in a much smaller package and without the usual six to seven figure price tag.
The hull shape and general appearance are closely related to the flavor of the bigger boats, most distinctively the sheer and the flared bow, which has been scaled to a more sophisticated proportion.
See the plan review by Robert W. Stephens in the Designs section of the January/February 2013 issue of WoodenBoat magazine.
| LOA...........20' 0" 6.1m LWL...........16' 4" 4.98m BEAM........ 7' 10" 2.39m DRAFT/ hull.. 9" 23cm @ dwl DEADRISE at transom... 13 degrees HORSEPOWER...... 70 - 150 BOAT WEIGHT including 90 hp motor...1400-1600# (635-735 kilos) depending on materials and options* DISPLACEMENT 2000 lbs (909 kilos) @ dwl Pounds Per I" immersion 372# (169kilos) *weight @ designer's suggested materials; different plywoods plus different fiberglass weight and optional gear will change boat weight. |
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Platypus was beautifully built by Bear Creek Custom Boatbuilders (Eric Baxter) 252-745-9925.
| The boat is very fast, yet amazingly economical. She has been clocked by GPS at 42mph (36.5 knots) with five adults on board, with only a 90 HP outboard. Most boats of this size require a 150 HP package. As a matter of fact engine dealers, used to heavier FRP boats with deeper V sections, tried to dissuade us from using only a 90 HP, claiming it would be a "waste to have such a nice boat underpowered". |
| The boat is cold molded plywood, built over a jig/framing. Most of the "jig" becomes permanent structure. The construction employs a modified orange crate method that is both light and strong. Note that this boat is aimed at efficiency of materials for performance, but is not a stitch and glue "introduction to building type of boat" if built from plans which includes full size patterns for the "jig". If you are familiar with working with wood, epoxy and fiberglass, the fully templated plan will present no problems for an amateur builder. We can also supply CNC cut kits for these framing components, so the build is very suitable for the competent amateur. This model would also be an excellent choice for the small commercial yard. |
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As can be seen from the top picture at left: The first and third and fifth frames are temporary as well as the frame sides. All of the rest of the structure stays in the boat. The forward sheer clamp and the stringers have been installed to complete the hull framing.
The aft bottom is planked with a single layer of 1/2" (12mm) and the forward bottom uses 2 layers of 1/4" (6mm) ply with staggered seams. The sides will be planked with two layers of 3/16" (4mm) ply . The side planking uses the Ashcroft method which means both layers run diagonally in the same direction, the seams in the two layers are staggered (see below).
The entire boat is epoxy and fiberglassed inside and out with one layer of 1208 biaxial fiberglass glass cloth which makes for a very strong tough boat. The complete encapsulation of the wood creates a very low maintenance and a long-lived boat. The boat is painted with epoxy primer and the top coat is two part polyurethane paint.
Built as designed, the owner will have no more maintenance than a production built polyester boat.
The full size templates are shown above.
There are full size Mylar* templates for the hull framing parts. Included are: Stem and keel; temporary frames, permanent frames/doublers; bulkheads; transom and transom arc; bottom stringers. The frames and bulkheads and drawn with the notches located and sized for the side stringers. Each of the parts is color coded: Examples: bottom stringers - blue; temporary frames-green. The drawings are 1/2 of each frame, transom etc.. When tracing your parts on the wood you will simply flip the patterns. The use of the template patterns eliminates any need for lofting and ensures that your framework will be accurate and true. It is also much quicker and easier.
*Mylar is drafting film, which while it is quite expensive, is totally stable and practically tear proof. It is practically transparent, making it easy to orient on your plywood grain and allows for it to be used for both sides on one sheet. Halving the Mylar pattern drawings saves a lot of shipping weight.
Shown to to the left and above is a hull, fully planked and ready for fiberglassing. Above: She is ready for her exterior fiberglass sheathing. To the left, you can see the (white) epoxy thickened fillets at each seam. The first interior piece of fiberglass is being installed at the starboard side chine joint.
Visit the B&B Builders Forum at messing-about.com/B&B
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E-mail: designergraham@gmail.com for technical information or admincarla@gmail.com for ordering. |
B&B Yacht Designs, 196 Elm St., |
Photo at right by
Wave Crest Images www.info@wavecrestimages.com