32-Foot Cabin Cruiser "Sunfish". Part III.
We knocked off work last issue with the molds and ribbands all in place ready for framing up 32-Foot Cabin Cruiser "Sunfish". Before you proceed to frame her, see that all the seams that cross the rabbet line are fitted with what are called "stop-waters." With a half inch bitt bore so that it cuts halfout of each side of the scam and drive in a white pine dowel so that any water attempting to flow up this seam and cause a leak will swell up this pine dowel and prevent the water from going through.
You need steam and a steam box to bend the frames, of which there are forty pairs, each frame being about 7 feet long and 1 1/2 by 1 1/4 inches, though there is an advantage in having them square, say 1 1/2 inches, in that as you grab the hot frame from the steam box you can bend it on either of the four faces, whichever shows the most likely way to stand the strain. I have specified them deeper than they are wide for this reason The grain of the frame should be bent so that the plank fastenings go through the layers of wood and not through between the layers of the grain wedging apart, as it were, the layers of wood. If they are sawed out so that the grain would be across when cut on the narrow face you could never make a mistake in getting the grain right whichever one of the two narrow faces you bent against the ribbands.
Many people like to bend the frames "on the flat" because they are easier to bend that way but for the good of the boat they should be bent on edge, as that is the way they have to resist the strains An odd pair of gloves will be found very useful in handling the hot frames You need a number of 6 or 8-inch screw clamps and someone to hand you the frames from the steam-box Put the heel or lower end of the frame on the keel, your knee in the middle of the frame, and bend it just as if you were bending a bow to string it — bend it gently but steadily into place, and if you have a helper, which would be advisable, let him start to clamp the frame to the lower ribbands as you bend it down against them and follow on up to the turn of the bilge. If the frames are not steamed enough they will break, and if they are of poor quality they'll break anyway Rock elm makes a line frame as it bends with very little breakage and is strong besides.
Space off along on the keel and ribbands where the frames are to go and mark with chalk so when you are working fast with a hot frame you can sec just where each should go to have, them evenly spaced. Hold the heads of the frames well in to give the round, tumble-home curve at the deck. They are liable to straighten back, anyway, as they cool off.
When they have cooled you can nail them to the ribbands and remove the screw clamp to use elsewhere. Put the nails in slanting through the edge of the ribband into the face of the frame. Don't nail through the side of the frame from the inside of the boat into the ribband, for you will scar the sides of the frames.
By bending frames in hot this way you twist them with a monkey wrench so they lay flat ready to receive the planking without beveling them. The heels of the frames should be cut so that they butt flat together at the centre of the keel and have a slice taken off the under corner so that instead of the square corner of the frame touching the top of the keel they will fit flat on top of it out to the edge where the rabbet is bevelled off to receive the edge of the garboard.
Drill a hole down through the frame and drive a 2-inch galvanized boat nail through into the keel at the heel of each frame. Then take some 1 1/4-inch oak boards 4 inches wide. Lay them on edge over the top of the keel and mark out the shape by running a pencil along the outside of the frames, marking this angle on the board. Then saw out this shape, or, clamping the board in a vise, rip it off with a draw knife and true it up with a plane. Fit the floors forward of amidships forward of the frames, and those aft aft of the frames. You can then bevel this floor off so that it gives an additional surface to which to nail the planking.
Rivet each floor to its frame with three round wire copper nails riveted over burrs on each side. Keep the upper edges of all these floors in a true line so that the keelson will not require much cutting and fitting when you run it fore and aft over them. Away up in the ends where the frames make a sharp V, use wider boards to cut the floors out of and shape them down on the top or take an oak knee slabbed up into 1 1/4-inch thickness, and get floors with a natural crook to them.
The keelson, a 3-inch square yellow pine stick, 24 feet long, is then bent down on top of these cross floors and held securely in place exactly over the keel until you bore holes with a long 1/2-inch auger bitt through keelson, floor and about 3 inches into the keel. Measure the exact lengths with a sliver of wood and cut corresponding lengths of 1/2-inch galvanized iron rod for drift bolts. Tap a slight head on one end by clamping it in a vise and using 3 ball pene hammer — a machinist's riveting hammer — to spread the metal. Then put a galvanized riveting ring over the end of it and drive the bolt home. One of these at each floor will hold her backbone solid as a rock, and if the keelson ends lap onto the deadwoods forward and aft and are bolted fast there the whole forms a very rigid truss.
Construction Plan of 32-Foot Cabin Cruiser "Sunfish"
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