Narrowing Chugger’s Bows



	Narrowing the bows on Chugger is a relatively simple procedure.  The absolutely simplest way is to draw it out on a smooth surface, full size, and take the measurements from there. This is a form of lofting, but I will make it a relatively simple procedure. I continue the 3 to 1 ratio when narrowing the bows, adding 6” of curve length for every 2” of inward curving of the bows. For example, the maximum narrowing of the bows for a 12’ boat would be 18”…9 on each side. To narrow further you will have to start the curve further back.  So… for a bows that narrows by 12” per side or that is a width of 24”, you will need to extend the curved area length by an additional 9-12”(This means starting the curve further back on the hull).  When narrowing the bows, the length of the boat comes into consideration too. I gage that for every foot of extra length the bow may be narrowed an additional 4” from the original 18” to give a minimum width of 14” for a 16’ boat. You will also have to move the start of the curve back by 24” or a total of 60” back from the maximum front of the bows. Inclining the bow transom does not change this formula; you simply measure from the forward most part of the bow transom.
Even narrowing by 18” on the 12’ version, you will be getting into the cabin area and will have to add curve to the front of the cabin roof.  Here is where the drawing comes into effect. This will give you an idea of the shape that the final boat will take. You can do all the building without the drawing, but you might not like the result and then it is too late. To do the actual building, you will attach the sides to the transoms and use a spreader to get the final shape, then mark and cut the roof and deck panels from the actual shape of these assembled hull panels. This is the cut and fit method. The biggest issue here is to get the boat absolutely square before tracing the lines on the roof and deck panels. You will also be narrowing the front window area so you must consider this when framing out for the front window. The drawing will help you with some of the measurements, provided you have about the same radius curve on the drawing as the actual panels take. Use a piece of the same ply as the side panels to layout the curves on your drawing, this will give you a relatively accurate curve similar to what the final panel will take. You only need to draw the boat from a bird’s eye view, to where it straightens out.  Narrowing the bows will give less room in the cabin (hence the lengthening of the boat), but will lessen the frontal area of the boat, providing less of a wind impediment. 

When framing the panels, you may have to notch the chine logs and some of the roof and deck framing to accommodate the curve. These notches or kerfs will allow the chine logs and framing to bend to the curve properly. Fill the kerfs with thickened epoxy after attaching to the side panels, to make them whole again.

You don’t have to narrow the bows to lengthen the boat, but you have to lengthen the boat to narrow the bows by more than 18”.
If you have difficulties with these directions, please feel free to email me with your questions. 
Steve:               numbaoneman@boatbuilding.com