Cobia is a type of small power boat that is enjoying great popularity as a combination day cruiser, overnighter for two and sport fisherman. The cabin has two comfortable berths, an enclosed toilet room and small but adequate galley space with ice chest, utensil and food locker, sink and stove. There is storage space for gear under the berths and in the forepeak. Abaft the cabin there is more than twelve feet of cockpit, ample space for loafing or fish­ing. The "bridge" can be covered during poor weather with a folding navy type can­vas shelter as shown dotted on the out-board-profile drawing.

The length overall is twenty-five feet six inches, beam is eight feet five inches to the outside of the planking, and the draft is about two feet depending upon the weight of fuel, crew and equipment. The round bottom hull form is such that mod­erate power is required for best efficiency, so at least 100 horsepower is recommended. With the engine shown the boat will run at about 20 miles on hour while 150 horse­power will boost the speed to about 24 miles. Of course, if the boat is lightly loaded with stores and fuel the speeds will be a little faster in each case.

Before any wood can be cut, the lines of the boat should be drawn full size on ply­wood or building board as described in texts on boat building. From the full-size drawing, templates are made for the stem, keel, etc., and the section molds are cut and assembled. Most builders would prob­ably build this boat with the frames bent on the outside of ribbands spanning the molds from stem to transom, so this means that the thickness of the planking, frames and ribbands must be deducted from the sections, which are drawn to the outside of the planking, before making the molds. This, too, is explained in boat building books.

Day cruiser, fishing boat, overnighter for two—Cobia is 25 feet 6 inches of inboard versatility.

The plans show smooth or carvel plank­ing, but there is no reason why the planking cannot be lapstrake. In this case the planking thickness can be reduced to % inch. The planking would be fastened through the laps to the frames and also through the laps between frames, with cop­per nails riveted over burs.

The superstructure is modern in appear­ance, yet simple because the round at the top edge of the cabin is accomplished by working off the upper edge of the doubling strip that takes the ends of the cabin beams, and the forward corners of the cabin have rabbeted posts at the joints so outside can be rounded with a minimum of difficulty Speaking of joints, do not fail to use a bedding compound wherever a joint is made. Use a regular marine bedding com­pound in cabin joints, under the toe rail, cabin molding and guard, and under all deck fittings. In the joints between the stem parts and the keel use a heavy coat of thick white lead paste. Bed the cabin sides and cockpit coamings against the deck structure with Minnesota Mining and Manufacturing Company's EC-1159 com­pound. Even some professional builders are lax in this matter of bedding, the lack of which results in annoying leaks at first and finally in the inevitable rot that is so expensive to eliminate.

Hand in hand with bedding is the matter of ventilation. The minimum number of vents to be installed in Cobia is shown on the plans. Many boats develop rot in the transom and adjacent areas because they are closed in practically airtight. Note that Cobia has two vents in the transom and the space under the stern seat is open for passage of air.

The fuel and water tanks are shown of welded Monel, a nickel-copper alloy that is highly resistant to corrosion and is strong. Such metal will last a lifetime and it has gotten to the point just now where welded Monel tanks made by fabricators with modern welding machinery can pro­duce tanks at no more cost than copper. Packless valves are recommended for fuel lines. Approved types are carried by marine supply houses.

Various items of equipment are shown on the plans, identified by catalogue num­bers of manufacturers. Naturally it is pos­sible to use items of equal quality made by other manufacturers. Just do not use makeshift junk that will give trouble later. This particularly applies to the engine con­trols, both throttle and clutch. There are many good controls now on the marcet, such as the Morse Model S, that are ideal for this boat.   One reason for having a hydraulic reverse is the low effort required for gear shifting, and this combined with a good control at the wheel box makes for an outfit you can rely upon at all times.

It is always best to use highest quality materials. Stick to durable materials such as silicon bronze for fastenings, mahogany or cedar for planking, good white oak for frames and backbone, genuine waterproof plywood where this material is specified, and marine paints. Boats of these ma­terials will last a long time when care is taken during construction to eliminate causes for rot. After the hull has been framed give all parts two coats of a wood preservative like Cuprinol and after plank­ing give the inside a couple of coats. Also apply the preservative to parts of the deck structure in generous quantity.

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