The El Toro Project

The El Toro is an 8 foot racing dinghy conceived in "Bull Sessions" at the Richmand Yacht club in 1936. It has become a recognized class of over 11,000 one-design yachts and is the most popular "dinghy" on San Francisco Bay. Check out the RYC Juniors in action here.

This boat is the perfect choice for new sailors young and old.

About the project:

Plans for the El Toro can be obtained directly from the class association. They are very extensive and complete, although a bit dated in construction techniques. I chose to combine the stitch-and-glue building method with the jig based method shown on the plans. I wanted this boat to be class-legal, and to make more than one of them, so the accuracy obtained by using a jig was well worth the extra effort. I also transferred all of the key components into my CAD software in order to create full-scale templates and confirm the accuracy of the plans. If anyone is interested, they can get the file in ModelCAD, or DXF file format.

Construction of the boat is broken down into several well defined stages listed below:

The Jig

The jig consists of a stern and bow template, and three frames which define the shape of the hull. A central keel fits into notches in the frames making the whole structure interlock. I used inexpensive 3/8" MDF for these pieces. Templates were drawn full-scale using the computer and printed on standard lettersize paper. Index marks allowed these to be taped together into a full-scale template. These templates were then glued to the plywood using 3M-77 spray adhesive. This stuff is great and allows the paper to be peeled off later without a mess. I used a jigssaw to cut around the lines. Using this method I was able to achieve dimensional accuracy of 1/16 of an inch on the frames. Computers are great! The frames sit on a simple frame made from a couple of 8 foot 2x4's. The ends of the "keel" are angled appropriately to match the bow and stern profile on the plans.

Cutting the parts

Bow and Stern transom pieces were cut out of 3/4 inch MDO (Medium Density Overlay). MDO is finished on both sides and is very strong. I bought a single 4x8 sheet for around $65 and that will produce bow and stern transoms for five boats! The sides an bottom of the hull use 1/4 inch plywood. I decided to go cheap for this first boat and used regular ACX. (The boat is finished on the outside with a layer of 6oz glass and coated inside and out with West Systems Epoxy, so we'll see how she holds up). I am using Luan for the next boat. Should be less work filling voids etc with the Luan.

The side pieces were lofted using dimensions extracted from the CAD plans. I used a bendable spline to make a nice smooth curve connecting the points. A circular saw was used to cut out both sides at once. Simple. One sheet of 4x8 ply will give you one side and one bottom piece with room to spare.

The bottom pieces are a little trickier. I laid one of the plywood sheets on top of the jig and clamped it down at the ends. I then used a pencil from underneath to scribe a line along the "keel" of the jig. I then clamped the two bottom pieces togther and cut along this line. When placed back on the jig they meet perfectly. Using the stitch-and-glue method, "perfect" just means you have to get things within about 3/8 of inch of each other. You can have large "whoopses" with the saw and they will get covered up when you glass the seams.

Now on to the fun part!

Assembly

Assembly consists of clamping the bow and stern pieces to the "bow" and "stern" of the jig. I drilled holes in the transoms near the edges in preparation for attaching the sheeting. The side pieces were placed on the jig and "zip" tied to the bow and stern transoms. The bottom sheeting was then placed on the jig temporarily to mark along the sides for the final cut of the bottom sheets. While the bottom sheets are clamped together for the saw cut, I drilled holes along the edge and loosely installed zip ties. Then the sheets are opened up and laid on the jig. The zip ties help hold everything in place while you make any last adjustments. Once everything is in place, tighten up all the zip ties and you are ready for phase three!

Thwarts and Knees

Before you can start epoxying everthing in sight, you need to make a few key components. The first is the daggerboard trunk and center thwart. This assembly will provide much needed support once you pop the boat off the jig. Knees and other items parts are cut out at this time as well.

It's a Boat!

At this point, with the zip ties holding everything together, you can remove the clamps and lift the boat off of the jig. The boat is amazingly rigid at this point and will hold its shape quite well. Once you put the center thwart in position to hold the sides apart, the boat's shape is now fully defined. You can recheck critical dimensions at this time, length, breadth, etc. Now it's time to start glassing.

Construction of the hull from this point forward is very straightforward. For a thorough description of glassing techniques, follow this link to an excellent web site.Stitch and Glue

Mast and Boom

The boom was constructed using traditional methods shown on the plans. The mast however, took advantage of some readily available components allowed by the class rules. I had access to several fiberglass and/or carbon fiber sailboard masts. These are the perfect size, but you need to attach a sail track to them. I obtained a material called flex-a-rail, made by Bainbridge. It is a PVC track material used for awnings and such, but works perfectly for a 1/4 inch boltrope. I roughed up the PVC and mast and epoxied the track to the mast. Works great. I attached the gooseneck and boom vang fittings to the mast by using Kevlar core from a small length of halyard, soaked it in epoxy, and wrapped the fittings to the mast. They will never come off. I screwed a small Harken cheek block to the top of the mast for the halyard. Rig complete. I phoned Hogin sails in Alameda and a week later had two sets of sails. Rudder and daggerboard were made out of wood and varnished.

Finish Painting

I laid down a layer of 6oz glass cloth for scuff protection on the outside of the hull. Several coats of epoxy to fill the weave and I was ready for paint. I used Brightsides polyurethane from Interlux over three coats of primer. Paint scheme was patterned loosely after my '93 Malibu Echelon, since it would often ride atop the ski boat.

Transporting

An interesting side note: The mast hole in the foredeck is the perfect size to slip over the ski pylon on the Malibu. The stern transom tucks up perfectly against the back seat of the ski boat. The hull of the El Toro wraps around the engine cover without any part touching each other. A single tie down strap keeps the dinghy held firmly in position. I also have a set of Yakima racks for my van roof when I leave the ski boat at home. When I am going without the kids, I can toss the boat inside

my van with room to spare. The mast will also fit entirely inside the van. (full size 3/4 ton Chevy van)

Pictures:

Click on a thumbnail for a larger image.