CB Trunk and CB installation pivot ~ Easy Build Boat from Plans

Board pivot.

Taking it a step further today. Found a chunk of 3/8 bronze rod and cut it to length for the pivot. Previously, I had marked the inside of the interior trunk side for the pivot point prior to cutting out. THIS IS IMPORTANT as it helps locate the pivot point indicated on the plans. This can be done after the fact, but it was very easy to locate this way.

I removed the starboard side of the trunk and then drilled a 3/8 hole through the CB and the side after ensuring that the holes were lined up well. These will be drilled oversize, filled with epoxy, then redrilled when all is said and done with. This will provide a more permanent pivot, and one that wont swell up and contract with the variance in humidity. good practice on any hole through plywood. as it also protects the interior layers from delamination.

Next, the bronze rod was placed to keep the board and side aligned and a hole was drilled upwards to the starboard panel that is temporarily tacked in place (sheet rock screws).

I then tested the board for pivoting, and marked its maximum extension. Note: I had been wondering if the board went to vertical, and the answer is, "no". the board is at a small angle to the hull in the full extended position as it is indicated on the plans. The picture on the plans matches what it looks like in real life. The top of the board does not protrude past the top of the trunk, and with the cap on, the travel of the board is limited to this angle.

board angle matches the angel of the forward kingpost

After assembly, I did notice that the very top front corner of the board still needs shaping to the foil, as it is currently a flat non-hydrodynamic shape. this will easily be rectified with the wood eraser.

The pin itself will reside in two layers each side o 3/8 ply. the first layer will have a hole in it to receive the pin, the second layer is the seal. I plan to bed it in polysulfide sealant. This sealant is actually removable in case we ever need to take out the board for maintenance.

finally, a look at my choice for the tip of the blade. This may be pared down knowing that we have more of an angle than I anticipated. The trailing edge and leading edge need to be extended a little more. This would be most problematic when the board is partially raised (normal downwind practice). Very little protrudes past the bottom in practice, but it is bothering me.

I got tired of running out to the garage to find the electric/18V drill, and switched over the the bit brace. I actually can remove the screws, and then torque them just right in less time than running the drill. Insert photo of me slapping my forhead and saying "Doh!"

3/15/14 - update

got the sides of the CB trunk glassed today with a layer of 10 oz glass set in epoxy, and cut out the support pieces for the CB pivot (3/8" 4X4 panels, four of them). Additionally, further shaping of the Centerboard to make the portion where it emerges from the trunk more hydrodynamic. Photos below.

While I was at it, I cut the slot out from the bottom of the boat. It was marked prior to removing the mock up from the boat, so it was a simple job with the Japanese backsaw. 10 minutes tops.