Installing Genoa Tracks on Redwing's Cabin Top
By Judith Blumhorst, DC
1985 WWP-19 #266 "Redwing"
Why put genoa tracks on the cabin top?
In two words, the answer is "Upwind Performance." Potter 19 sailboats aren't exactly famous for their ability to point. It's easy to see why, since most skippers follow the directions in the owner's manual and run the jib sheets outside the shrouds.
With the jibsheets outside the shrouds, the sheeting angle is about 30 degrees off the centerline of the boat. Compared to most sail boats, that's a very wide angle! The classic place to put your Genoa tracks is about 8 or 9 degrees off the centerline for a working jib (usually defined as approximately 100% of the area of the foretriange). Classically, you want a sheeting angle of about 9 or 10 degrees off centerline for a 115% jib. The typical sheeting angle for a 150% Genoa is about 12 degrees off the centerline.
The outside edge of the cabin top is as close to the centerline as I could get and still have room to run 8 lines aft to the cockpit later on. I placed the Genoa tracks just outboard of the usual location for the teak handrails. It's about 15 degrees off the centerline.
Another consideration was the structural load on the boat. The cabin top is very strong where the cabin wall makes a corner with the cabin top.
Another advantage of putting the tracks here is that I can reach the sliding cars easily from the companionway and cockpit. I can adjust the lead forward and aft for different wind conditions to keep the right amount of tension on the foot and leech of the jib, and get just the right amount of twist in the sail.
Clew height of the jib is another consideration. Both the P19's strom jib (32 square feet, which is about 50% of the foretriangle. Mine is custom made at 42 square feet of area, which is about 65% of the foretriangle area) and the lapper (67 square feet, which is about 100% of the foretriangle) have very high clews. That's a nice feature on a cruising jib, because it makes it easy to see under the sail while you're underway. The high clew also makes it possible to put the tracks on the cabin top; you couldn't put them up there if the clew were lower. For the deck-sweeping factory Genoa, you'll probably have to lead the sheets lower to the side deck .
"The most impressive Potter had to be Redwing, Judy was up to 4:AM the day before the sail working on her. Judy mounted the genoa tracks on the cabin top to get better performance to weather. I gotta tell you, this potter really moves upwind. We were out in the Bay with about 20 MPH. wind and two-foot chop and I couldn't catch her. She was pointing extremely close and really moving. I later found out that her crew David, not Judy herself, was doing the sailing. . WOW! I was impressed." Jerry Barrilleaux, Commodore, Potters Yachters, Feb 17, 1999.
Why You May NOT Want the Tracks on the Cabin Top
There's a tradeoff between performance upwind and the "don't scare the new buyer (or spouse)" factor. With a wide sheeting angle, you can't point for beans, but the jib tends to spill wind when it gusts or blow mightily -- so you don't scare the novice sailor by heeling a lot.
In heavy winds, in order to spill wind and reduce heeling, many cruisers adjust their tracks somehow so that they have a wider sheeting angle of perhaps 15 to 25 degrees. They have a gadget rigged called a "barberhaul" (which would not be hard to do on a Potter 19 using the factory Genoa sheet lead) or they can use a different track. On race boats, the skipper doesn't want to sacrifice pointing ability so s/he requests more "rail meat" -- s/he tells the crew to go sit on the upwind rail and act as human ballast to keep the boat from heeling too much.
So if you're new to sailing, or you don't want to scare your spouse, you may not want to put your Genoa tracks this close to the centerline.
Hardware and Materials
The track I selected was Schaefer 1" black anodized aluminum race track (part #40-64, about $40 per section), with a four foot long section on each side of the cabin top. I chose it mainly because I really liked the Schaefer cars.
Schaefer cars have a polyethylene liner inside the stainless slide that is held captive by the design of the car and slides easily under load. I selected car #303-86, a lined car with a spring loaded swivel block and a spring loaded stop pin that's easy to pull, even if your hands are cold and wet. They are reasonably priced at about $45 each. (They look just like the 303-72's in the picture above, but the303-72's don't have the liners in the car.) Each track required two plastic end-stops (Schaefer part #74-35, about $2.50 each).
For cleating the jibsheet, I chose a camcleat and with a fairlead on a swivel base (Harken #240, SWL=300 pounds). This allows me to trim or release the jibsheet no matter where I am sitting in the cockpit. I bent the metal arm holding the camcleat down to allow me to release the jibsheet without my having to stand up. (I'm only 5'5". My 5'11" husband could raise his arm high enough to uncleat it while seated, but I couldn't. So I bent the arm down a little)
Mounting the tracks required about thirty stainless steel 1/4" x 1-3/4 flathead machine screws, with 1/4" fender washers for backing and locknuts. Mounting the fairleads required four 4" #10 flathead machine screws with fender washers and locknuts.
Miscellaneous other materials were needed. I used West System epoxy resin and colloidal silica thickener #406 for making fillets (1/2" epoxy cores around each hole I drilled). I used Life Caulk (Thiokol polysulfide) for bedding the machine screws for the tracks for it's flexibility and long life. Life Seal (combination silicon and polyurethane sealant) was the bedding compound of choice for bedding the track ends and fairleads, for it's superior adhesion than silicon and it's ease of removal. (You might need to change a damaged Genoa car or camcleat).
The usual assortment of mixing cups, sticks, nitrile gloves (do not use latex gloves -- they melt when they contact epoxy!), rags paper towels, alcohol (for wiping up excess caulking), and blue masking tape was on hand (the kind that doesn't dry out and stick almost permanently to your boat.)
The whole project cost about $350 in hardware, stainless steel fasteners, caulking and miscellaneous supplies. It took about twenty five hours spread out over four or five days.
All you need is a cordless drill/screwdriver, a good set of drill bits up to 1/2", a cone shaped rasp for the drill, a few box wrenches, a set of socket wrenches, and a screwdriver.
The Layout and Drilling
Never put fasteners through holes drilled a wood-cored deck (or transom). "Huh, what's that?" you say, "You gotta drill through the wooden cored cabin top to attach the tracks." Okay, here's the trick answer -- you don't drill holes, you build fillets.
To prevent inevitable wood rot in your cored deck, you need to make a fillet for every place you want to drill a hole. A fillet is an area of solid fiberglass or epoxy to drill through. When you drill through a fillet, you don't cut through any wood. There's no wood grain exposed, just plain resin or well-saturated fiberglass
If the manufacturer didn't give you a filleted area to lay your track, you can make something just as effective with a drill and some epoxy resin. If you drill a 1/2" hole in your cored deck, fill it with epoxy, and then drill a 1/4" hole in the epoxy, you will never have to worry about core rot. It's a damned lot of work, but you will never have to worry about core rot. Never. At least not from your work!
First I laid out the track on the cabin top with masking tape and marked the 1/4" holes. I made sure the lead from the blocks on the tracks was perfectly fair to the camcleat. I taped the track and camcleats to the cabin top with blue masking tape. I ran lines through the blocks and fairleads to be sure the leads were fair. Remember the old saying, measure twice and cut once.
With the track was taped to the cabin top, I drilled the front and back 1/4" holes for each track through the track and bolted the track to the cabin top. Then I drilled the holes in between, using the actual track as my guide. Then I drilled the 1/4" holes for the track stops. Finally, I marked the holes for the camcleat and drilled 1/4" holes there also, even though were going to be fastened with #10 machine screws.
Drilling the 1/4" holes went well, but when I went to the 3/8" drill bit, the top layer of gelcoat and coarse fiberglass shattered and chipped. So I used a drill rasp to grind the top skin of the hole a little each time and then used a slightly larger drill bit.
Finally, after drilling about 90 times, and grinding about 60 times, I had nice clean 1/2" holes through the gelcoat, fiberglass, and wood core.
By the way, be sure to remove the carpet-like headliner from the area you're drilling. If you don't, the drill bit will catch in the fibers of the headliner and break the drill bit, and maybe some piece of your anatomy .
(BTW, there are alternative methods of building fillets, such as drilling the correct diameter hole and them reaming out the core between the top and bottom fiberglass skin. It's never worked well for me -- I've scratched up the fiberglass. It takes longer to do. But other have had more success than I using this method, so there must be something to it. See the Gudgeon Bros/West System book Fiberglass Repair for more info.)
Making Epoxy Fillets
Making the fillets is the easiest and most fun part of this project (except sailing the boat to weather after you're finished)
Here's how you do it: I draped the interior of the boat under the holes with plastic drop cloths to protect the interior from drips. Then I used a q-tip to coat the edges of the exposed balsa wood inside each hole with plain epoxy resin. The plain epoxy soaks a millimeter or two into the balsa to seal it.
Next, I taped the bottom of the holes from the inside of the cabin. I mixed up some epoxy resin and thickened it to a consistency halfway between ketchup and peanut butter using colloidal silica. I added some white coloring agent to make it a nice white to match the gelcoat (even though nobody will ever see it.)
Next I put it into a heavy ziplock bag and cut off the corner. I squeezed just enough into each hole to be as close to perfectly level as I could manage. With a little practice you can get within 1/32 to 1/64" of the surface. Let it cure until it has completely hardened, up to 24-36 hours if it's cold out. (You'll need to heat the boat with lamps or a heater if it's below 40 degrees F.) Wait patiently, don't go on to the next step before the epoxy has fully cured.
Mounting the Tracks
Now I was ready to drill the final holes and mount the track.
I marked the centerline of the first and last track holes. I drilled a 1/4" hole precisely through the middle of the rearmost fillet and put a machine screw with a nut in to hold the track still. Then I drilled a hole in the front of the track and put a screw and nut in to hold it. With the track in place, I drilled the holes in between, dropping a screw into each hole as I went.
Then I crossed my fingers and took all the track off to inspect the alignment of my new holes in their fillets. Every hole had gone through the center of the fillet. I hadn't come close to drilling through wood. Finally, I was ready to mount the hardware!!
The final step in preparing the holes for mounting the hardware and sealing with caulking was to bevel the edges of the holes a little bit (just a 16th of an inch will do it) with a grinding cone. There's a special kind of drill bit that will do this automatically for you, but I don't have one so I use a cone. The little bevel helps to hold the caulking and greatly reduces the possibility of leaks.
I used the Life Caulk (polysulfide) for mounting the tracks. It lasts practically forever. It sticks to everything forever. It's hard to remove anything set in polysulfide after a year or two, but I don't think I'll be needing to remove the track for any reason. It's yucky, messy stuff to use. I prefer to use a caulking gun rather than those small squeeze tubes and I keep lots of rags and rubbing alcohol around to clean up as I go. I wear cheap latex gloves and change them if they get sticky. You have to be super careful, or else you end up with "gook and putty" everywhere.
Every hole in the track got a dab of polysulfide around it. Then I took a nail and smeared a little inside the hole. Then I attached it with a 1/4" screw, 1/4" fender washer, and locknut. A little gook came through each hole to the cabin roof underside, which is good.
For the track stops and fairleads, I used Life Seal (polyurethane and silicon combo) to bed the screws. That's so that I can remove them if I need to replace a broken part. All bolts were backed with fender washers on the underside of the cabin.
Here's what Redwing's cabin top looked like when I finished.
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