The second weekend in a row and March 14/15 provided some great 50 degree weather to work on the boat. I continued to cut the balsa pieces to match the contour of the transom. The photo below shows the final transom core pieces bonded with bracing material to hold it in place so the Core Bond could cure. Although hard to tell, the bracing board is approximately parallel with the horizontal bottom of the boat. This was completed on Saturday.

On Sunday morning I removed the bracing and sanded the areas where I dropped core bond in the section forward of the transom. This needed to be a smooth surface for bonding balsa core. The core bond sands pretty easily compared to using a filler of thickened West Systems. I used large sheets of paper to trace the cutout sections just forward of the transom on the stdb side. The paper tracing was then transferred to the balsa core and the pieces cut using a knife.
Below is a picture that shows fitting up the pieces. The edges were sanded/cut as needed. The gaps between pieces aren't real critical, as they would be filled with core bond. Note that the balsa pieces were fabricated as one large piece that I then cut into smaller sections no larger than 12 inches. This allows the pieces to conform to any irregularities and insures a good bond to the outer skin. The picture below is a view looking straight down in the stbd cockpit locker. The top of the picture forward and left side towards the keel.

The view below shows the area in the cockpit locker bonded. Note the core bond between the core section joints. I left a tab of the old inner skin around the entire new core area so when the fiberglass is bonded, it will be bonded over the tab to provide structural support. This means that there are still some areas with wet core. I'll live with it, since I know the boat won't crack if there is hull slamming in rough seas!

This is my chance to make sure the exhaust is never again the culprit contributing to wet core. The picture below shows where I created a dam at the bottom of the hole where the fiberglass exhaust tube will be bonded. I filled the area with thickened epoxy. The dam leaked so I have a little puddle forward of the hole. It's just a cosmetic problem, and nobody but me and the world reading this blog will ever know about it. The top of the picture is stbd and right side is looking aft. The white triangle is sunlight overexposing an area - hey I held the camera below in the locker, so this was a blind shot!

Remember that the area on the stbd side by the transom and the backstay chain plate was like mush? The photo below shows the new and improved cored area. The section with the upper bonding tab I left on the stbd side was dug out, ground clean using a wire brush on a flexible shaft, then thoroughly dried with a heat gun (it was very wet). The void space was filled with core bond. That way if water was coming in by the seam, it will be stopped before reaching balsa. The core bond was also used as a layer to isolate the transom from the new core on the stbd side, again to prevent water migration if there ever was a problem in the future. The photo below is looking up at the intersection of the transom, stbd side and deck joint.

The center area above the transom is shown. Note that there used to be a piece of plywood strengthening the area behind the rudder gudgeons. That's the gap that shows along the top seem. This won't be needed with the stronger fiberglass plate that is there now. Before bonding the inner skin, I'll use thickened epoxy to fill the area and provide a contoured surface. Plan is to bond the inner skin as a flat surface, then bond a fiberglass tape to connect the surface with the adjacent tabbing. It's just too hard to try and work all the complex angles with a big sheet of resin soaked 17 oz biaxial cloth.
Note to self - no backing plate on the stbd side padeye for the back stay (see just the nuts and washers in lower left portion of picture). Fix that!

Starting the "easy" areas to core. This means working on your knees instead of hanging in a locker upside down. Warren was working on grinding out the inner skin from the stbd quarter berth while I was working on the transom. He needed a little calibration on how to use the Fein tool because he punched through the outer skin in a few places.... more exterior sanding, filling and fairing work to do. I continued this work on Sunday after the core bonding.

Here's another potential water source. The engine intake hull valve does not appear to be isolated from the core. Plan is to dig out underneath leaving the valve in place, then build a dam using a 6" diameter plastic mixing bowl that has been cut off leaving about a 2 inch lip. The dam will be filled with thickened epoxy and provide an area where the fiberglass cloth can be bonded to for structural strength. I'd replace the vale, but it is in great shape, so no sense destroying it taking it out. It has been routinely lubricated, operates freely and shows no sign of corrosion.