Stem Rabbet Line

Comment

Comment by Clyde A. Phillips on July 3, 2010 at 3:36pm

Bob mentioned to me the fact that toward the forward end of the apron the rabbet leaves the apron, meaning that Point A (which is the top edge of the rabbet) is removed from the apron. This gives a void between the apron and the plank. This needs to be filled with wood (a two-way wedge) so that it will not become a water tank.

Also, the directions (next to last paragraph) on putting the bevel on the bottom of the apron works only if the new apron is NOT glued to the keel below. Bob said that he may just bevel each layer as he goes (with a table saw) and just leave it there. My recollection is that the keel/apron joint was put together with bedding compound (Dolphinite way back then) and not glue. Check the joint, do what was done originally.

It all this raises questions, send them to me and I’ll see what I can do to help.

Comment by bob mitchell on July 2, 2010 at 9:15pm

CLYDE DISUSSES THE APRON
The attached picture shows you a “point A” that is the intersection of the side surface of the keel and the bottom aft corner of the frame right on the frame station, which is the aft surface of the frames on the forward half of the boat (on the after half of the boat it is the bottom forward corner; the dividing line between forward and after sections is the “mid-section,” which is that place where you have a larger space between the frames—the full 11 ¼ inch; this is typical wood boat construction). All the Point A’s should line up on a fair curve that is the lower edge of the bottom plank. The shims may have been used to get the apron in the correct position to make the frames come to that point. We did not use the words “Point A,” but they are the rabbet line routed into the stem and keel.) “Point B” is the bottom of the frame at the outboard edge of the apron. Point B is where the bottom after corner of the bottom frame hits the apron. I can’t believe the guys building the boat needed shims, because these boats were built to patterns and the top surface of the keel and deadwood where routed to shape using patterns lagged to the keel/deadwood unit. They may have been put in by those who replanked with boards. That fact indicates a shortage of boat building knowledge. You never know what you’re getting in an experienced boat of unknown history.



So, it looks (from here) what you need to do Is to make sure you know where those Point A’s are and see to it that there is solid wood in the keel/deadwood up (from the bottom of the keel) to that point. Get a good batten about 4’ longer than the length of the new apron section and spring that batten on the keel so its top edge is at all the Points A. A batten about ½ x 1 x the length needed (plus a couple of feet on each end) will do the job—actual measurements are your option. Nail at each Point A (again, top edge on the Point) with 6d nails; again your option. If possible scribe a line along the top. Where wood is above the line remove it. If there is no wood at the line put some there. With the keel plumb the top of the keel should be level. Remove all punky wood and replace with good wood. Then after the keel is in good shape you can start putting together the new apron.



After it is all glued up and in clamps, scribe a line on the bottom of the apron along the top of the keel. Locate all Point B’s on the edge of the apron. Lay out a curve through all Points B with the batten and scribe a line there. These two lines mark the angle of the bottom of the apron that must be planed off. That may be easiest done by removing the new apron piece from the boat and putting it upside-down on a couple of horses. After sanding the glue off the sides of the new piece you should pencil lines at the frame stations. The lines are plumb on a level boat and the stations are 11 ¼” apart horizontally (don’t follow the curve of the apron for this). You will have to put your first frame station line on the apron while the apron is in position, the others can be put on when it’s on the horses. I call it critical that these lines are accurate.



Don’t forget the that the forward end of the apron is also beveled. Hopefully you can get that off the old apron. With all this I leave you. You have much work to do so get to it. I’m going to sit in front of the TV and watch a good show while eating some ice cream.



Peace,



Clyde