When we built the big daggerboard from the same cedar stock as the hulls, there were a couple of days where the workshop smelled like Christmas and the forest as every plane stroke during the board shaping released more cedar aroma. And then it all got sealed up with epoxy, glass and carbon, never to be seen or smelled again. Until today. It was major surgery, but at least it smelled great.
Recall the prior post where you saw how “high aspect” the foil shape was. Over 12:1, and that’s likely causing some stalling, and contributing to the howling noises when Ravenswing got up to speed. The experts agreed, it needs a more aggressive rounding shape up front and more severe taper. So we pulled out the original plans, did some tracing, resulting in some fattening and shortening fore/aft.
The board is a bit under 2-3/4″ at its widest. The exit slot at the bottom of the hull is 3-5/8″. So the new shape is going up to 3-1/3″ and 28-1/2 wide, for a 9:1 ratio. The last 11″ wide aft are too thick, so that has to go. The front 18″ or so are too narrow, so that area will be augmented over the existing shape.
Step 1, saw in to one’s well built, but poorly shaped big ass board.
Then we cut 1-1/4″ off the aft edge of the rectangular head of the board so it will fit in front of a new shock-absorbing heavy rubber insert we’ll add to the back edge inside the daggerboard trunk on the boat. Great idea from Keith!!!
Got the board level and plumb up on a makeshift table, ready for a new tail end. This feels like we’re building an airplane wing – fun.
Now we need to transfer the skinny pattern into wood and foam core. We had the off-cut from the shape-checking guide board to use in transferring the angle to the table saw. Note the light piece of wood against the saw fence is the same as what was on the dining table earlier.
So while the rest of you were out partying Friday night, we played with string and wood blocks in the tiny shed.
And in this final photo, see how the new shape will butt up against the rectangular head section. It’s those little sharp triangular areas on each side that sit on the exit slot block at the bottom of the boat when the board is deployed. This weekend we’ll fill in between these wood blocks with foam core and get this new tail shaped and ready for fiberglass. I have a feeling adding the right shape to the board on the front half will be much trickier than this aft-half job.
For those Farrier builders reading this, fear not, this surgery did not touch the super-strong area of the board (embedded hardwood insert and 6 layers of carbon uni the full length of the board). Thankfully the surgery started about 4″ aft of all that.
And while on the subject of good smelling wood, here’s a gratuitous shot of last weekend’s homework. This time the missus didn’t just hand over a photo, it was a whole how-to book of iron pipe projects. This is marital bliss – Jeanne gets to display her treasures and Greg gets to see all her treasures find a nice consolidated home. Win win, and the vacuum glides along like the shelves aren’t even there!
Wow. Big job and it looks great!
On Sat, Mar 17, 2018 at 12:43 AM, F36 #005 Ravenswing – Trimaran Building wrote:
> cartersboat posted: “When we built the big daggerboard from the same cedar > stock as the hulls, there were a couple of days where the workshop smelled > like Christmas and the forest as every plane stroke during the board > shaping released more cedar aroma. And then it all got se” >
Awesome work! I LOVE the shelving and plan on doing the same in our new home! Can’t wait till you visit so you can help us….hhahahah. But really…..