Dagger Bagger

Sometimes it’s possible to worry too much about these projects. Last time we wrote of not knowing a reasonable technique for bulking up the daggerboard shape. After some careful measuring, it needs 5/16″ at the most, and most of the add will be 1/4″ or less.

We dug around in leftover building materials for some 1/4″ divinycel 80 (5lb density) foam core that had been saved for anymore interior panel making. Fortunately for timely efficiency (hard to get this stuff quickly) there was just enough.

The little pile of scraps was all we had left of three 4×8′ sheets from 2015.

Next we made a fresh vacuum bag with the last of the Stretchelon plastic, but it wasn’t quite big enough. So for a first, tonight we’re trying standard 4mil plastic sheeting from the hardware store. For a simple, flat part like this it’s working fine.

Thanks again to whoever dreamed up laminating curved panels under vacuum pressure. So satisfying to watch it work. This extra foam core will be very well formed on to the board.

Along with running out of vac bag film, we’re out of the fabric breather that lets air flow inside the bag, and soaks up excess resin. A quick web search at lunch today turned up an airplane builder who uses paper towels! He said use four+ layers. It was soooooo much easier to keep in position tonight, and nearly free. We’ll let you know next time how it worked.

In that last shot notice the darker seams in between the pieces of tan foam. That’s epoxy being forced up, and that will make the shaping process more difficult. The tools need to move between the hard glue lines and softer foam without gouging. There’s the downside of using all the scraps instead of single full sheets. We’ll just have to be careful.

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Sunday with a glue gun

We got back to the daggerboard reshaping this morning by digging out a bag of foam core scraps. This would take longer, piecing together odd bits. But it’s better than waiting days for a new shipment, and that stuff is expensive. So with the little tabletop bandsaw we got busy.

I’d forgotten that the 5lb density foam core is difficult to shape with sanders. For anyone else doing this, these abrasive wheels on an angle grinder so a nice job without leaving bad gouges. Easily found at Harbor Freight, etc.

Here after rough shaping.

Then we cut off the last trailing 1″, which will get rebuilt later with solid glass and putty so as to achieve a sharp knife-edge for smooth water exit.

After lunch we ran down to Napa Autoparts for some body filler. Since this will be buried under the fiberglass, we’re not worried about exposing bondo to the sea. And it has the huge benefit of hardening in 20 minutes. So the afternoon was spent flipping the board over, sanding one side while the other had its next skim coat hardening up. It took four passes to get where we’re happy this new core will give a fair fiberglass’s surface.

Ok, the tail end is ready; now we need a plan for bulking up the forward portions. Here’s how much it needs to grow:

Anyone have a clever idea of what to use for bulking up the board? Jeanne thinks craft-shop balsa that come in thin strips, adhered to flexible matting. Or we could rip very thin cedar strips on the table saw. I’ve heard of “core mat” but don’t know anything about it. Any good experience is most welcome.

Ah, the smell of cut cedar!

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!

Boatyard punchlist

Ravenswing came to the Spaulding Boatworks yard for minor repairs to the deck and port float hull from the mast fall. We had a small list of “well, while we’re here…” things to do. 

First up was maintenance and installation adjustments for the engine. In retrospect we should have bought an extra-long (30”) shaft, to get the propeller lower in the water and avoid some of the cavitation we’re experiencing in waves. With some surgery we could lower the motor 2.5” in its mount box. 


Then we bought longer control cables to facilitate routing them up higher out of the way in the equipment room. Also changed the lower unit oil for the first time; it was in good shape after the break in period. 
The big task turned out to be a redo of the escape hatch. It had been installed with the hinges on the forward edge, but when it opened, the swing was deep through the water. Also, the hull recess didn’t properly match the metal hatch frame, and I had offset the hinges a bit to compensate. Which of course had led to some water getting past the seal at high speeds. So what we thought was to be a couple hours maybe for hinge adjust and reset turned into a job across four days. The hull flange had to be chopped 3/4” along the top and then that offcut bonded down on the bottom edge. Then the hull had to be rebated around the hinges for the new (proper) swing pattern. We think the hatch will just clear the water now when opening. 

Those pics show you the new black Petit Trinidad bottom paint. Gone is the snazzy white look,  but this proper bottom black looks pretty serious. And we paid the yard pros to do a real boot stripe this time. (Straight, unlike our amateur wavy job last year).

We’re tackling our daggerboard vibration / howl issues in two ways. First is stopping the slop when the board is down. The trunk is 88milimeters wide inside, except for the top and bottom three inches that had extra glass wrapped over from the deck (and hull bottom) into the trunk. The hull builder did that for strength, but not to the plans, and it made the opening only 81.5mm. I made the daggerboard head (via shims) just a hair under 81mm to fit the opening, allowing 6.5mm slop once the Board was down. So to compensate we ripped long 3mm clear fir shims to bond on each side inside the trunk. They got epoxied coated and painted on the workbench, then epoxy-putty bonded in. That was tricky; buttering the 5’ long pieces and carefully sliding them up into the trunk, not letting the putty hit until the placement was right. Four went on each side. Bottom paint still needs to be applied to these inside the case, up to the waterline. 

Part two will be some reshaping of the board, to be tackled when we take it back home after weighing the boat. 

Final finish paint to the deck repairs went on Saturday so we could launch today.  But a 9am call from the manager informed us that paint didn’t get warm enough and had glazed over dull. So they’re redoing it, hopefully for a Wednesday launch. Also meaning we still don’t have the boat’s weight for the mast builder. 

On Friday afternoon I helped the project manager attend to the 54-yr old hydraulic scale. Turned out to be a simple low-on-fluid problem. As the sun was setting we hatched our plan to check the calibration. Here was our victim. 

The data plate shows its curb weight at …6,970lbs. Crazy to think that little forklift weighs close to our 40’ x 28’ boat. Anyway, up it went

And the scale shows …

… a very accurate match to the tagged weight. Certainly good enough for our mast-build needs, and we’ll put this scale in the crane rigging on Wednesday. 

As much as we need fall rain, we’ve had enough to totally screw up this haul out trip so just another 36 hours sans rain would be great. 

Anybody wanting to go for a motorboat ride Wednesday, Sausalito to Richmond, get in touch.  

It took 25 men…

Thanks for your patience everyone while things went quiet over here. Ravenswing has made various short daysails but we’ve had a lot of business and family commitments this fall. In mid September we convinced Charlie to tow his F27 TriChi to theSummer Splash multihull gathering in Southern Cal. After racing to Catalina, the skipper gets to anchor in a whole fleet of fast-movers.

It was a great weekend – thanks again Charlie and Jim. It was bittersweet to NOT have that be Ravenswing’s first coastal trip, but the boat was not at all ready for ocean work. In Marina Del Rey, walking thru the trailer yard Jim said, “hey, there’s a little MacGregor powersailer like yours in the ’90s”. I got a few steps closer, and dang if it wasn’t our own time capsule! Kind of sad that it’s sitting there neglected, but also a trip to see it exactly as we sold it 20 years ago. Weird. 

From LA it was ‘more west’ … at the Hong Kong Maritime Museum I was reading about the first Chinese junk that sailed to England in the 1840’s. 

And we thought Ravenswing has some heavy helm issues – imagine their nights at sea:

We don’t know how far sailing will take us, but the Hong Kong Yacht Club would not be a terrible stopover. 

Finally after 12 days in Asia humbled by the scope of port automation projects like this in Quingdao

attention came back to the boat. Thinking more about the heavy-effort steering, we realized that in building the rudder cassette we didn’t compare the F39 plans’ for gudgeon height above the water to our custom F36 stretched stern. The result is not enough forward rake ahead of the pivot point, so all the water force is transmitted through the tiller. See the red line drawn on the rudder here – that’s how much surface area in the water should be ahead of the pivot.

Here the straightedge shows how much we actually created (the left edge)

So now we will make a permanent shim inside the cassette that tilts the rudder to achieve this

Good news for the folks who’ve helped on this – there’s enough room in the cassette to make the needed insert, and hopefully not cut in to the amazingly strong and complex carbon work. 

The other major change is to walk away from the linkage & pivot steering system. We reported 2+ years ago about not believing a simple straight tiller to the rudder would work.  But we haven’t been totally happy with the gear, and decided to mock up a simple tiller approach:

Charlie and I strapped this junk in place and pulled off the dock to find out if the tiller can swing far enough side to side between the tower legs. Yea! The boat can still spin in its length and is sufficiently agile at various engine / hulll speeds. The existing gear actually lets the rudder turn too far, causing stalls or being a brake. We’ll set up the new tiller for soft landings on the tower legs to safely limit the rudder travel. That’s the new theory anyway. 

A question for the engineers / experienced out there- what shape will make the strongest tiller that is narrow side to side ?  We want the maximum distance throw up against the tower, so a skinny tiller is important. Charlie’s suggested some type of carbon I-beam configuration. Square tube? Round tube? What do you think?

She likes her boat 

That’s the co-owner in the purple hat, enjoying her first sail on her new ship. And how nice to share the day with her pal Leslie!

As a student sailor, Jeanne asked for a job aboard but I countered with asking her to get a feel for the boat on all points of sail without worrying about techniques or traffic. Charlie came to sail (already the Ravenswing veteran co-driver) and RickW sailed aboard for his first time. 

The Marin waters provided ideal sailing today – flat seas, lots of boats to catch, breeze to charge upwind at 9kts, and full sunshine. With lots of hands aboard, the owners got to relax and check out various places to sit. Jeanne is the first to sail from the aft swim steps, and it’s a great little spot. With the jib reefed, the clew is up high yielding lots of comfortable foredeck. Compare last week’s photo with this and see we got the excess sail properly tied and zipped in to its cover. 

Full main and reefed jib is very comfortable with apparent wind in the teens. So much to learn about trimming this mainsail; here it’s getting better but you’ll see we couldn’t get halyard tension:

If you can zoom in to the top you’ll see SOMEone attached the 2:1 block for the halyard to the wrong spot on the fancy Skateaway Design headboard, so we lost 5″ of upward travel. Fixed that back at the dock afterwards – the day was too nice to stop, douse the sail and redo it underway :)

As we headed for Sausalito I wrestled my tiller away from the guys and spiced things up with a full charge up the channel, way above the motoring speed limit, dodging all forms of watercraft. The crew anxiously called out every boat and paddle board as if I was a blind man, but we kept on to go get a view of Tom Siebel’s Mod70 tri Orion, Sig45 open deck luxury racing cat, and huge Protector with four 300hp outboards. Wow does that guy put millions in to the sailing habit. 

So while the super rich have staff to keep their boats expertly tuned, the mere mortals have to solve their own heavy weather helm. This morning we installed the shims on the daggerboard head. Definitely tightened the board in the case, but it didn’t help the rounding up. So now it’s on to making rudder changes. Rick is concerned the trim tab may be to blame, and we’ll get the original rudder painted this week to try on Labor Day. We’ll make a new spacer to push the top of the rudder aft and the bottom forward; the axis point may be wrong. Still a worry to solve this nagging issue. 

To cap the day we headed north towards San Quentin in a breeze that did some gusting off the Marin shore. Rick was driving, with his handheld GPS as a speedometer. It’s like a drug, you just want more knots… The water was fairly flat so we cracked off to a reach and hit the gas pedal a bit. 14kts was pretty easy. That’s her new ‘personal best’, and only a reefed jib and baggy main luff

But the best part of the speed run was Jeanne in the cabin enjoying the excitement from a comfortable window-side couch; we’ve come a long way from scary wet rides on the F27. 

Tinkerers, let’s hear your thoughts on the noisy dagger. It’s shimmed and it got that slanted trailing edge a few weeks ago. At 14kts it makes a bloody racket. How are we going to quiet this down (without hiring MOD70 Orion’s shore team)?

A sailboat on a day like this in a place like this is hard to beat.  Leslie’s getting a big view of the Oakland / SF bridge; it’s your turn readers, just drop us a line. 

We shouldn’t be fabricating on the last day!

Fish or cut bait, so they say. It’s time to go sailing, even if a few interior trim details aren’t done, or the plumbing isn’t 100% complete. But the last shop / building day began with making custom clevis pins for the steering system. 1/4″ SS rod here getting cotter pin holes then cuts to eight 2-3/4″ pins …

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So while Install Steering was intended as a one hour repeat of work done many months ago, final parts and tweaks took all the way to 3pm. All good now and the steering feels great – the water will be the real judge.

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During the daggerboard edge refinishing we also squared up the bottom to a nice knife edge. I am further incentivized to keep this thing from touching ANY underwater obstacles. No repair hours, please.

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And here it is yesterday, painted and heading up on deck. This is NOT a trailer boat :)

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We got in on deck and stood it up to drop in to its trunk, but after repeated tries / angles we couldn’t clear the roof. We’re not confident that the dagger shape is the same as the cutout in the hull bottom, and if we need to enlarge the slot we need to know NOW, with time to rebate and re-epoxy. So Jeanne and Griffin made patterns from the actual daggerboard and we messed about enlarging the slot a bit tonight.

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Epoxy seal went on tonight, primer in the morn and new bottom paint tomorrow and Sat before launch. That’s cutting it close.
Leslie took a whack at the motor controls and this all mounted nicely. Looks easy but the cables and wires passages through the boat were tough. Many more hours chewed up there.

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So that’s a wrap, and transport activity starts in the morn. The must-do punch list is short, and bigger bolt-on items can come later in June and July.

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If the logistics go as planned (boat hull fits on the trailer, for example) we’ll be floating by Sunday. Let’s hope all the wheels actually roll this boat to the water! Stay tuned.