Team Seacats

I’ve received some feedback in the form of doubt with respect to the recent project of the carbonfiber strips reinforcing the basement wall. To those folks, I offer up this video, assembled by Fortress Stabilization Systems as proof of concept. (If I can figure out how to embed a raw video file again).

Things are REALLY heating up in the quest to breach 50 knots average over a 500 meter course powered by nothing but the wind. There are four major camps that have vessels each with their own unique design aspects. These guys have been working hard for the last couple of years to iron out their machines, but now that the French flagged Hydroptere has hit the water after an extensive retro-fit, everyone is stepping up their game to be the first to fifty.

It should be noted that the current record is held by a windsurfer at just under 50 knots. The windsurfers that have set the last two records have been sailing in a purpose-built “ditch” in the sand just next to a shoreline that yields really flat water and a stiff breeze. While I’m certain that it takes a great deal of skill to sail a windsurfer at these speeds, there’s a part of me that feels like sailing in a narrow strip of water built by a back-hoe isn’t being honest to spirit of sailing. Three of the four craft listed below also need flat water but typically find a stretch of shoreline that is shallow and subject to an off-shore breeze. Hydroptere is truely unique among these speed demons because she can handle the open ocean…at 40 knots. Below is a bit of a summary about each. Each site is really good and has tons of photos and video.

WotRocket – These are relatively the new kids on the block. They started their idea about four years ago and have touted nationalism and an effort to “finally break the French windsurfing fraternity’s stronghold on the coveted world speed sailing record”. Their claim to getting to the 50 knot barrier is to utilize “supercavitation” technology first known to be utilized in a Russian “Shkval” torpedo which could reach 200+ knots underwater. The trick with any of these crafts is that foils tend to cavitate and loose lift at speeds around 40 to 45 knots. Who knows, maybe they’re onto something

SailRocket – These guys had an extensive development cycle – I remember watching videos of their r/c test boats years ago. They’ve probably been in as much or more of the spotlight as the others in the years past and have been on a lengthy development process over the last several years that included some scary looking failures. Every time out, they’re getting better and better and have choosen a strip of water off the coast of Namibia in Africa as their site. They have a unique cantilevered sail design that is intended to provide lift of the vessel to reduce it’s dependency on floatation or foils to get clear of the water.

Macquarie Innovation These guys probably have the most experience as their vessel is a descendant of the previous record holding vessel “Yellow Pages Endeavor”. They too have suffered a dramatic failure when the wing exploded last year due to a minor failure. I can’t find much information about the status of their project – but they could easily pop up on the radar with a “hey, we broke the record”.

Hydroptere
- we’ve covered Hydroptere here before – but in a nutshell, it’s a trimaran and a more traditional “sailboat” than the others. She has an exceptionally narrow central pod and tiny little outer pods…these are there to only give the boat stability when she’s not underway. Extending down from the two outer pods are two very large tapered foils extending down into the water that angle inward toward each other at roughly 45 degrees. These foils are suspended through a nitrogen charged cylinder to give them some suspension, but more importantly, the ability to adjust the incline. She is equiped with a “T” foil rudder to control attitude and is steered from a racing seat and steering wheel like you would see in a car. The recent retrofit saw several changes – I think the largest of which (and the one they haven’t mentioned much about) is the very large wing mast. Not only is she is also the only vessel in this list that is using fabric sails, but she is readily capable of sailing fast in the open ocean – something that none of these other boats can even consider.  The fact that Hydroptere can do this is what has everyone watching while she trials in flat water in Marseille, France.

Before I get too deep into this one, no, I’m not crazy and yes, this will really work! The engineering behind it is sound and there’s evidence of it’s success elsewhere!

The problem: A good friend of mine recently purchased a fixer-upper house and knew that there was some problems with the 60′ front basement wall….the front yard was trying to get into the basement and had cracked the (what we later found out) incredibly inadequate 4 inch block that was used to build the foundation. The wall had a long horizontal crack, nearly the length of the wall, and in some places had bulged out 2 inches. Before he signed the deed, he had estimates. Jacking up the house and completely replaceing the wall = $30,000 and he had two estimates in the same range. What was interesting, however, was a third company that proposed an $11,000 solution by gluing carbon fiber strips to the existing wall. This wouldn’t straighten it but would stabilize it to keep it from shifting further. Naturally, this caught my attention and investigation into the process caught my imagination. I said to Mark, I have all the tools to do this and we can do it for less than $1,000 and do it better! (Mark seems to have a lot of faith).

I don’t have much of a “before” shot – but here’s an angle looking down the wall. Remember, this is only 4″wide block where it should have really been, at the very least, 8″ (better to be 12″).

The company that proposed this had video on their website that showed their testing of the process. A test wall they had constructed was loaded up with a hydraulic ram and cracked at only 500 pounds of force. Now that the the wall was cracked and buckled in a very similar fashion to this one, they applied their carbon strips (which were pre-cured) with vacuum. Once cured, they fired up the ram and put more pressure on the wall until it failed. Their test wall, even with the pre-damage, now withstood 12,000 pounds of pressure before it yielded – and it wasn’t the carbon that failed – the carbon, where it was epoxied to the block, sheared the concrete below it and came off the wall taking a whole lot of concrete with each strip. It was the shear strength of the concrete, not the carbon and not the bond of the carbon to the concrete, that ultimately failed.

So why carbon and not something less expensive like Kevlar or even fiberglass? The answer is because the carbon, for all practical purposes, will not stretch. The Kevlar, while strong, will stretch a little more than carbon and any movement in the wall can degrade it over time.

We decided to do one better and instead of using a pre-cured strip (which would be much easier to work with), we decided to vacuum bag wet uni-directional carbon directly to the wall. Before we did this, however, we needed to seal the block and even out some of the major irregularities (like grout lines). After masking off a vertical 6″ area every 4 to 5 feet, we rolled West System epoxy with slow hardner onto the wall with a 4″ paint roller. We made sure to get it really wet so the epoxy would soak deeply into the concrete…and soak it did. It sucked it up like a sponge. Then we came back with epoxy thickened with milled fiberglass (in hindsight, cabosil would have been easier to work with), and filled in the grout lines and squeegied it on the whole surface to fill in most of the pock-marks in the wall. Then a layer of peel-ply went ontop of that would smooth out the filler even more and give us a really good surface for secondary bonding once removed. There was still some minor irregularity in the wall – but it wasn’t critical. The epoxy at this stage did a couple of things for us. 1) it made the wall smoother so the carbon will be mostly straight and setup to handle loading in tension (what it’s best suited for) and 2) sealed the block so we could pull a vacuum over each strip.

Using 10 rolls of mastic vacuum bagging tape, we sealed the perimeter of the prepared areas and wetted out an 8′ long 4″ strip of uni-directional carbon fiber tape. A skim coat of unthickened fast cure epoxy was brushed onto the wall. The carbon strip went up followed by a bleeder ply of plastic (with tiny holes). Then a long thin piece of felt was applied to transfer the vacuum evenly followed by a top layer of vacuum bagging film. The amount of vacuum we were able to achieve was incredible and with the high flow of a compressed air venturi vacuum generator, we were able to vacuum up to five strips at a time.

After about four or five solid days of work (spread out over a month), we finished the repair and that wall isn’t going ANYWHERE. The carbon is sucked down so tight to the wall, you can see the compression in the weave of the fabric and it is physically part of the wall structure now. The vacuum and compression effectively “pre-tensions” the carbon and makes the bond to the concrete as strong as it can possibly be. There’s my carbon fiber concrete story.

While I was stuck without being able to update the website, the Archipelago raid was sailed and finished this morning. The French team, Team Kalix, Eric Proust and Romain Motteau win the event this morning with a score of 257 points and by finishing first at the last two checkpoints (earning 25 points each). Team Thule, Strandberg and Ortendahl, finished 2nd with 244.5 points. Our British friends, Team X-Leisure (Sunnucks/Farren) finish in third with 231 points.

The event saw a broad range of weather conditions – some days were incredible days of sailing with 15knots of breeze and the ninth leg was canceled after two hours of “sailing” due to a lack of wind.