Our buddy building the SR-71 Blackbird has posted a significant update where he’s building wing skins now and gluing them together. He’s using an interesting technique in both installing the internal structure and attaching to two narrow skins together in the mold. As for the inner structure, he’s using blue construction foam first gluing it to the skin half. Then he comes back with a hot cutting wire and cuts the foam flush with the top of the mold flange. After this is done to both sides, he applies glue to the foam and lays in a resin soaked piece of carbon fiber tow on the fine little edge of the skin where it will bond with the other skin and sandwiches the two halves together to cure. Although I probably need something a little more structurally sound than foam for the primary bulkhead, the timing is good as I’m still trying to perfect our hull halve blind joining method. While I doubt the necessity of using carbon in the seam, since it probably adds very little strength value, the use of tow to fill and help join the two thin sections is an interesting idea. I too used to use wedges to separate the mold halves but I have found that air pressure shot from a simple air nozzle usually does the trick much more easily and with less potential for damage to your mold surface. Link to the sled.

Originally uploaded by Team Seacats.

The Hydroptere team is on standby waiting for a weather window in which to launch their bid for the 500meter sailing speed record. Apparently the WSSRC has approved of their onboard equipment to be used to record the speed and distance data. I’ll keep you posted here or you can keep checking their site; Hydroptere

Gitana 13 (Formerly Innovation Explorer from “The Race”) set out a couple of days ago to best the Columbus Route of Discovery Record currently held by Steve Fossett’s Cheyenne (125 foot) catamaran of just over 9.5 days. Boy, wouldn’t Columbus be impressed that we can sail from Cadiz to the Bahamas in a whole lot less time than his five weeks!

Gitana had fallen slightly behind Fossett’s pace while sitting in some still weather. She had finally broken free when they had an impact with a UFO (Unidentified Floating Object) yesterday and broke the starboard rudder at the hull. Unfortunately a large chunk of that rudder is partially attached and is threatening to do further damage to the hull. The crew intends to send a person into the water to free the rest of the rudder to hopefully avoid a larger problem - but the great sailing weather is impeding this repair and they’re slowly trying to make their way toward land. They’ve given up on the record attempt. I hope they find some land soon and safely.

More info and some video on The Gitana Site.

Originally uploaded by Team Seacats.

I managed to squeak out a hull during the last several days. I vacuum bagged both halves using epoxy resin (I’m beginning to doubt the benefits of vacuum bagging these hulls in this situation), and got two pretty good halves. I glued them together along an external flange that will later be removed (I will probably join the future boats within the molds). For the purpose of verifying the correct amount of ballast, I thought it important to get the hull floating to determine if the waterline was where we thought it would be and that the CG for the ballast is correct. Good news; it’s right on the money. Now that I know a 4lb bulb is ideal, I’ll start the work on the lead mold and keel strut while I polish up this prototype. You’re probably wondering why the halves are different colors…well…I was experimenting with tints for resins for a feature yet to be announced….stay tuned.  The hull weight is just about at target at about 363 grams (.8 pounds) - durability really feels good.
 

       
  

The team abord Hydroptere (actually … French) is now waiting for a weather window in which to launch their attempt for the world speed record.  What a magnificent campaign. Hydroptere

Team RAF posted some video’s and pictures on their site from their adventure…check it out.

With my new sails sitting on my pool table, I decided I would finalize some of the rigging details in the next week or so. In order to do that, I needed some flat carbon material from which to make spreaders and a mast crane to replace the light-plywood I used for the test. At the same time, I wanted to test out some of the mold release waxes I have before I rely on them in the hull molds (I can continue to use the PVA but it adds almost two hours to each molding cycle). I’ve had two small .25″ pieces of plate glass I found when I moved into this house 8 years ago so I decided to use those to sandwich some carbon in and vacuum bag to a cure. I first put three coats of “Mold Release” wax on each glass plate and then took 5 layers of (I believe) ~5oz carbon fabric with alternating patterns, poured about 1oz of epoxy into the center, padded with polystuffing, inserted into a 1 gallon ziplock bag, and pulled a 20in/hg vacuum on it. After about an hour under the heat lamp, I disassembled the vacuum setup and found the glass was pretty firmly adhered to the carbon. We won’t be using that wax again!

After trying shots of air pressure with no success, I tried to insert a wooden wedge and tap lightly but one of the pieces of glass finally broke. I then resorted to a tool to give the glass a little more incentive; a hammer. After breaking the glass on both sides into pieces, I was able to scrape off the remainder and ended up with a relatively unharmed piece of carbon. It’s under 1/16″ and incredibly stiff - this stuff is amazing. I can probably get away with just three layers for these components. I think in this case, I’ll forgo the waxes and just use a plastic sheet between the glass and the lamination…I’ll get some bigger 12″x12″ glass for the next round now that I know this is viable.

 

Originally uploaded by Team Seacats.

Who is it?…Hydroptere…hydroptere who?….Hydroptere who’s about to put the hammer down on the world sailing speed record - that’s who!

Wow, 47.2 knots top speed now.  The Finian Maynard speed record of 48.7 knots over 500 meters is looking shaky and the 50 knot speed barrier is watching closely.  It looks like they’ve recently installed some high-tech GPS tracking hardware to satisfy the requirements of the WSSRC (world Speed Sailing Record Council). The most amazing thing is that of all the boats that have ever even approached these speeds, none of them can do so in the open ocean like Hydroptere can but wow…if there ever was a problem at these speeds, it’s going to be dramatic for those on board….Stay tuned!  Read more about Hydroptere at http://www.hydroptere.com

We have a phrase that for the time you drive a catamaran hard on a reach and the deck at the bow is just barely above the surface of the water, we get “bow sizzle” as the tip rips through the water at 18knots (20+mph) with a sizzling sound.  This video has some impressive bow sizzle starting about half way through…these guys were flirting with disaster! Most catamarans will suffer a pitchpole (ass over tits) if you drive their bows in this deep - the Nacra 6.0NA is a monster with a lot of reaching sail power and needle bows which make the boat incredibly fast but unforgiving. I really enjoyed the one I owned for a couple of years.

I vacuum bagged the first hull half today and it was a moderate success.  I just couldn’t leave well enough alone and after it had been sitting for a while, I removed the vacuum to attempt to remove a stubborn bubble in the rounded hull/deck lip.  I think that the problem was that there was no loose plastic right on that corner allowing it to press the glass into it.  I was able to make the situation better by removing the vacuum and repositioning the bag, but it looks like I re-introduced a lot of air into areas that had already started to firm up.  The net result was that there are a lot of tiny air bubbles in the lamination.

I tried a modified resin infusion method that I dreamed up in my head - it actually “mostly” worked.  After carefully placing the fiberglass, laying in poly-stuffing around the perimeter, and attaching 1/2 of the vacuum bag, I started with 4oz of resin and poured it in the center of the mold laying a thick stripe from stern to bow.  Then I attached the rest of the vacuum bag and pulled a vacuum on the layup.  The resin did exceptionally well to saturate all but a 1/2 fingernail size bit on the stern - I can correct that by putting a little more resin on that end next time.  The advantage of this method is that it saves some elbow grease in having to wetout the layup and it saves some materials by not having to put a layer of peel-ply over the entire mold followed by a complete layer of stuffing.  The drawback of this method (the same as resin-infusion) is that you are more susceptible failure of the part if there is a vacuum problem.

The picture below is the hull half after I started to remove it from the mold.   The outside finish is actually quite good.

This is actually the second iteration of testing the vacuum bag setup on one of the two molds. I first tried using rope caulk around the perimeter but I found it difficult to get the pleats in the bag to seal well. The pleats are necessary because of the concavity of the mold - it needs more plastic to fit. I found great success and relative ease by running a strip of masking tape along the entire perimeter of the bag and then pleating it by sticking the tape to itself in strategic areas. Initially, I didn’t think the pleat position really mattered and I placed them all right in the middle of each side. I found that both the bow and the stern were having trouble conforming because of their distance from those pleats. What you see here is two smaller pleats nearest the bow and two large pleats nearest the stern (and naturally, two large ones in the middle of either end). I was able to get -20 in/hg with this setup…and that’s all my venturi vacuum generator can create … it’s more than enough for vacuum bagging this lamination.

The only drawback to the tape method is that it is still going to be tricky to use with PVA on the mold - I will not be able to reposition the tape once it is adhered because it will lift the PVA covering the sticky side of the tape if I do.  Of course, I still had the same problem with the rope caulk around the perimeter.  I may try to mask off the outer edge of the mold to keep the PVA from getting in there.

Sizing the plastic sheet also proved to be important.  I took a piece of strong and measured the length of the surface of the mold and the width (pushing the string down into the cavities).  It ended up with almost exactly 4″ of extra width and length due to the shape of the mold…for a perfect fit.  I added an extra 4″ and the plastic sheet is 20″ X 56″ (this blog serves as my records too!).  I’m now working on the templates from which to cut the glass cloth.

We finally have another update from our friend in the Midwest working on his SR71 Blackbird Airplane Mold.  It seems that he’s just about ready to start making parts and are building leg fixtures into his molds. I hope he puts some cross bracing on those legs! That things going to be doing the hoola when he’s rubbing wax into it. (in case yer wondrin’, that thar is experience talkin’).

Team RAF has reached Key Largo and are finished!  Stay tuned to their blog as I’m sure there will be some story telling.

I’m flattered to have recently received an “annual Popeye award for excellence in sail blogging” over at the Horse’s mouth.  I’m not so sure I’m flattered of that photo though (that should teach me to be public in my goofiness!).  If you’ve not yet been to visit the Horse’s Mouth, you should.  He’s got some great active content from across the board (usually sailing oriented), including “Fish on Fridays”, and is credited with inspiring me to do some of the miscellaneous category stuff we do here. 

PS; it’s on now buddy…I’m looking for a picture of you!  If anybody out there can help point me in the right direction, I would appreciate it.

In all the mahem here, I forgot to point out that Team RAF is underway!  Be sure to check out their blog:

Adventures of the RAF