Completed frame  
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The completed frame

Here is the frame after completion of the fairing and cutting of the limbers.

This is a major milestone where the frame now definitely starts to look like aboat.

Braces

After cutting fitting all of the battens there were many small wedge shaped pieces of wood left over. 

I was worried about the stress between the motor stringers and the frames. The fear is that the aluminum angle brackets may twist out of shape or loosen with acceleration. 

To neatly take up the stress, wedges are placed astern of each frame on the bottom side (currently top) of the motor stringers. This will more capably transfer the stress from the stringers to the rest of the boat than the aluminum angle brackets with a very small addition of weight.

This has worked out well over the years with no signs of shifting or loosening, even with hundreds of hours of hard use.

 

wedge shaped sringer brace
Limbers

Limbers are cut in several possible ways. In the plans, the limbers are shown as notches cut at the same time the batten notches are done. This method leaves a rough opening and it is difficult to get the battens to lay flat in the notches.

An easier technique is to cut the limbers after the battens are in place and the frame is fair. A 1" core box router bit is used (leaves a round bottom cut). 

router limber jig
To accurately position each limber notch, a jig is needed. A simple router fence is not usable as the router is placed and moved over both the frame members and the battens. I removed two of the router base screws and then replaced them with socket head cap screws. These were covered with a stack of 1/2" washers. The washers were offset on the bolts to set the bit edge even with the washers. This will make the cut even with the edge of the batten.  Test on scrap pieces to fine tune the washer size and offset.

The depth of cut was set to 3/4". The cuts were made in a single pass. Make a test cut and go to it! Only ~100 limbers to go. Note that this depth is a bit on the small side based on experience cleaning the completed boat. Bases on this experience, I would recommend cutting the limbers in 2 passes with a final depth / height of 1".

Note that the limbers will often be underwater in the bilge. This means that they need to be well encapsulated and this needs to be done now, prior to applying the plywood as these will be very hard to get to onece the planking is applied. Each limber edge should be sanded to "break" the sharp corners. The sanding is best done with 80 grit sandpaper wrapped around a 3/4-1" dowel. Each limber should get 3 coats of epoxy. It should also be done prior to the final fairing to avoid having any drips / globs of epoxy on the top of the frame that would interfere with the placement of the plywood planking.

 

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