Centerboard Cap Overhaul on USA 7093 (Lindsay)


Introduction

Lindsay 505 #7093 is one of the most well known International 505's based on it's race record. Winning the worlds in 1981 (Ethan Bixby and Cam Lewis, San Francisco, CA), 1982 (Gary Knapp and Cam, Cork, IRL), 5th in 1990 (Ethan and Cam, Kingston, Ontario), 7th in 1998 (Ethan and Cam, Hyannis, MA). Some Pre-world and NA titles as well. Chuck Millican owned the boat up until the 2004 Florida Midwinters. I picked up the boat in April-ish of 2004 thus the beginning of the de-evolution of 7093.

  
 

Background to the Project

All cool boats have cool names. 7093 has been know as: Recreational Pharmacology, Complex Chemicals Kill, Nancy Says No and Sneakier. The decision was quite simple, Shampoo Effect. Fast forward to the day before the NA's, August 2004, Santa Cruz, CA. Mike Renda and I are going upwind with one of the Pegasus boats in Monterey Bay. We just happened to meet on the water in about 12 knots or so. Long story short, big bang!...Renda unhooks and comes in, we both say WTF! And see forward thwart shrapnel flogging on the jib sheet. Sweet, the forward thwart blew up. We made a decent repair that lasted our time in SC as we learned how to sail the boat in moderate breeze and swell. This breakdown combined with the wear and tear on seat tanks and fore-deck; along with being 24 pounds overweight motivated me to do some work.

The idea was for a new forward thwart, to refinish the entire boat and completely re-rig it. That is more like three major projects, and I own neither appropriate tools nor appropriate workshop space. No problem. I realized I was in deep when I was tearing out the broken forward thwart and decided to keep on ripping out wood. I ended up with no forward thwart and no CB cap. Shit, why not tear out the aft thwart as well...it was held together on the starboard side by a 22 year old 2x4. "I remember that windy reach in San Fran back in 1981...the thwart ripped right out of the boat, damn." Ethan Bixby, four hours after I picked up the boat from his house. I was in the St. Pete Sailing Center parking lot rigging it, and he came to check on me.

As much research as possible was performed with many 505 sailors to determine the best way to complete this project. Some dingy-park talk and lots of emails with Ethan Bixby, Lin Robson, Mark Angliss, Ali Meller, Macy Nelson, Nick Nelson, Barney Harris and tons of moral support from Erik Boothe (roommate at the time) and Casey Barnes (St. Pete Sailing Center Manager).


De-Evolution Part One - Everything Must Go

Take off all of the hardware. Easy. Except for all of the stripped screws and bolt heads that have been in the boat for 24 years. Lots of dremel tool action. I had a bunch of baggies and a sharpie marker so that I could keep "jib lead" stuff separate from "boom vang" hardware. That lasted for one bag, and everything was chucked into a big Tupperware box. So much for organization. I was able to eliminate some huge hunks of metal including: one aluminum shroud lever, two pairs of Schaeffer stainless eyes that must have a breaking strength of around 12,000,000 pounds and some huge bolts. I pulled about 10 pounds of metal fittings out of the boat that were replaced with much smaller, lighter fittings.

De-Evolution Part Two - Remove the Finish

Two options, sanding alone or chemical removers. After lengthy discussions, I went for paint remover to strip the majority of the finish off of the fore deck and seat tanks. I was careful to mask off joints and other difficult areas to be removed with sandpaper. The chemicals are pretty potent. I used nearly two gallons of the super paint remover from the toy store (Home Depot). It is a gel and spreads on well with chip brushes. After liberally applying to a section (1/3 of a seat tank at a time), cover the area with plastic sheeting, and let the remover work. The key was to keep the paint remover from drying out...avoid direct sunlight and keep it covered with plastic. Then scrape away the nasty gunk left over and let it dry in the sun before you put it in the garbage...there is a "spontaneous combustion" warning on the label, though I was never able to actually achieve an explosion. Also wear some chemical resistant gloves for the stripping. The paint remover eats latex like a fat kid eats cake.

  
  
  

Re-Evolution Part One - The Mold

While I was stripping and sanding the finish off of the mahogany, I began preparations to design and build a new CB cap and thwarts. I studied Mark Angliss' web page often, and came up with a plan. I decided to use clear coated carbon fiber for the new structural pieces. Basically, I wanted to make the work as unique as possible; twenty-four year old mahogany and twenty-first century carbon fiber.


The Design

I wanted to design the parts as weight-efficiently as possible. I utilized my Mechanical Engineering Lab at the University of South Florida and began designing the geometry of the parts in ProE. As soon as I was ready to start load testing the CB Cap in ProMechanica, I graduated and was pretty busy with coaching...but I had a good idea of what I wanted to build.

The Construction

Following Mark Angliss' instructions (web page and numerous email) I built the female mold. The mold was constructed from foam core board, generally used in mounting photos and posters. Foam core board is available at any craft store. Razor knives cut the board well, and hot glue was used to bond the pieces together. The entire cap was mounted to a sheet of plywood to make it rigid. Plaster of paris may be used to create a fillet radius for curved corners. After the plaster dries, sand it smooth with 220 grit. Once the mold is complete, apply wax to the surface of the mold. Mold release wax first, followed by McGuire's car wax. This was great, but in the end, the wax did not help in popping" the part from the mold. Trevor Baylis uses vaslene as mold release, but I did not find out about that until after the fact.

The Layup

Layup of the CB cap and thwarts was done in one session, and consisted of five layers of 5.6 ounce woven carbon. My little sister was my epoxy maker and I attempted to do the layup myself. Coincidentally, John Hirsch (USA 7678) walked in as we were in the middle of everything and put on a pair of gloves and helped with the layup. Wearing two pairs of latex gloves at a time helped minimize the mess.

  
  

Re-Evolution Part Two - Seat Tanks and Foredeck

After getting all of the wood stripped and sanded, I thought I was ready to begin building the epoxy back up. Everything I read stated that the better (ie. more) the boat is sanded, the better the end result will be. I lived the motto of "just one more day of sanding". This ended up being "just one more week of sanding", but it paid off in the end. All of the wood was sanded to 220 and prepped for epoxy and cleaned several times with denatured alcohol, using the two cloth method.

Epoxy build-up began using West 207 (Special Coatings resin) and some squeegees. Four thin layers of epoxy was laid onto the wood. If it was longer than 24 hours between coats, the previous coat was sanded with 220 to remove the blush. A layer of one-ounce fiberglass was laminated over the fore deck and also on the forward seat tanks for added strength. The following pictures show the epoxied wood, the new carbon aft bulkhead, and the new red floor. I painted the floor a bit too early, more on that later.


  

CB Cap Installation

This simple task seemed to take forever, and I was itching to get everything done. I spent a countless number of hours delicately sanding and fitting the new carbon cap into the boat. Attaching the cap was pretty straightforward. I created some wood "tabs" and bonded them to the seat tanks for the outboard sides of the thwarts to mount on. The new thwart was also tied into the bulkhead that connected the old wooden thwarts. Slow hardener was used to ensure a long pot-life so that I was not rushed during this process. Once the new CB cap and thwart was in place, it was clamped and enclosed in the heated garage to cure.

  

Preparing for Awlgrip

I had decided to use clear Awlgrip as a topcoat for the seat tanks and fore deck. Awlgrip has a proven track record in the marine industry as offering a beautiful finish and excellent UV resistance. I followed the instructions regarding prep for rolling and tipping the Awlgrip by hand and went at it. Again, the key to a great finish is in the prep-work...meticulous sanding and cleaning. Top-of-the-line mohair rollers and badger hair brushes were used for this detail work. I was worried initially, as the Awlgrip layed down terribly, but after patience and lightly tipping, the Awlgrip becomes self-leveling. The brushing additive used for rolling/tipping Awlgrip makes this self-leveling possible. Lots of effort was put into making my garage as dust-free as possible for the application.

  
  
  

Re-Evolution Part Three - Fitting Out

The re-build and re-finish is now complete, and it's time re-rig. The idea was to rig as simple and as light as possible; I was not going to try and re-invent the wheel. I had spent tons of time looking at other boats and charged all of my cordless drill batteries. So I started installing the hiking straps. Since I changed the original Lindsay “box” shape of the forward thwarts, I lost a place to anchor the forward end of the straps. I bonded two small blocks of wood to the kevlar floor of the boat, one on either side of the trunk. The blocks are (2x3x1)inches, and would give me a solid point to screw down the straps. Following the bonding, I “carboned” them into the boat.

The Regression

So NOW it is time to begin drilling holes. As mentioned above, I started with the hiking straps. I drilled holes to screw the eye straps down....drilled a bit to far (into the kevlar floor) and water came out of my first hole. After a major panic attack and lots of four-letter words, I calmed down. I had read plenty of stuff about how to dry out wood/laminates/coring etc. I started drilling small, shallow holes radiating out from where I first struck gold, many weeped water when the drill bit was removed...nearly all of them produced small bits of wet foam core.

The next step was rather frustrating. I took a sharp razor knife to the perimeter of my hot red floor, and tore out the kevlar skin from the transom to the diagonal bulkhead. I did this as carefully as possible, as to not cause any more damage to hull, now that the structure of the boat is seriously compromised. After removing the floor, I covered the cockpit with a plastic “tent” and heated/fanned the area as much as possible. I dried the boat for nearly two weeks, leaving the foam as dry as possible.

The damaged foam areas where filled with new foam, and I prepped the area for a new floor skin. I layed a new carbon fiber floor without too much trouble; again going with the “Fire Red” paint. I used the Interlux non-skid additive to yield some texture to the floor. It was simple to apply:

  • Apply one coat of paint to the floor.
  • Sprinkle the non-skid over the wet paint with a salt shaker (I actually used a pepper shaker).
  • Allow paint to dry, then vacuum up the loose non-skid particles.
  • Apply second coat of paint.

I just read about using salt/sugar as a non-skid “applicator”. Apply the paint with salt/sugar covering the top surface. After the paint has dried, wash the floor to dissolve the particle, leaving a textured surface. I have not seen a floor done this way, but I sounds like it would work.


The Fit Out

Most controls are led to the CB cap including: ram up, trapeze twings, outhaul, cunningham, jib luff tension, rake and shroud tension. The vang is led to the CB cap as well, under the main sheet. One significant addition is the use of a separate spinnaker sheet and guy. It is basically “big boat” style, with a 4:1 purchase on the guy. We like this system, as we can fine tune the guy while wire running easily, and eliminated the twings makes our jibes faster.


Garth Reynolds, USA 7093

Editor's Note: USA 7093 has since been sold to Stephen Gay and is located on the West Coast.