Lunada Design » Sailing Monohulls

Cabrillo Prototype Build Underway

lunadadesign — Tue, 12 May 2009 02:17:35 +0000

Work has begun on the first Cabrillo dinghy for kids

I was finally able to squeeze enough time out of my schedule to get the parts cut out for the Cabrillo Dinghy design. Things have been hectic around here ever since the start of the new year. There are something like 6 boats under construction right now in some very interesting locations around the world.

I have been able to quickly move along on the Cabrillo over the last few days. The plans were printed out as full sized templates on a continuous roll architectural plotter. The templates were then cut-out and taped in place on two, end joined sheets of 4 mm marine ply. I used a can of paint to spray around the edges of all the templates and then removed the paper so I could cut-out the various hull panels.

The identical panels were clamped together and sanded to the final outline as a matched pair and set aside.

I started wiring the bottom hull panels first and then added the transverse bulkheads and the major longitudinal form. The bulkheads all fit together with opposing slots so that the whole thig just slides into place correctly.

With the bulkheads wired, I added the side panels of the hull and set it aside for tomorrow, when I will fillet the whole assembly and take out the wires. If everything goes as hoped, I could have the boat ready for this weekend and the annual Messabout at Utah’s Starvation Reservoir.

Cabrillo Skiff – the next step

lunadadesign — Wed, 29 Oct 2008 22:53:05 +0000

Phase 2 Design Study

I’ve shown the Cabrillo Skiff at a couple of well trafficked Internet boating Fora now (Boatdesign.net and Sailing Anarchy’s Dinghy Anarchy Forum) and have had a host of comments to digest. Along with those comments, I have cooked up a few changes of my own for the design. The boat shown in the following renderings represents the collected enhancements, if you will, for the Cabrillo Kid’s Skiff concept.

I have widened the aft side decks just a bit. While the changes are not really very radical, they are wider. I figure that most of this will be addressed by each individual sailor as they tweak their boats to suit their own preferences. I’ll probably see a nice use of adhesive backed neoprene, or maybe even some color keyed, indoor/outdoor carpeting along the rails, as the boats are modified for best comfort and rail edge radius.

The forward deck has been raised, as have all the joining surfaces that relate to the foredeck height. All the primary curves, as well as the resulting swept surfaces have been checked for fairness, and develop-ability (nice word, huh?)

The new deck height does a bunch of things for the boat.

1. Water will be shed much easier

2. Forward areas of the boat will see enhanced buoyancy

3. Interior deck surfaces will have a slightly greater drainage angle for shipped water

4. The mast pocket is deeper, providing a much higher degree mechanical of support.

There is now a “Turbo” rig option for the Cabrillo, complete with a carbon bowsprit from a windsurf mast section, making it a pretty economical adaptation. The new, larger main is 80 sq. ft. with a spinnaker that is just under 60 sq. ft. in area. The larger main should provide a real power difference on a boat this size. The spinnaker is on the kinda tame side of the equation, as this is a training boat and its real mission is to give the new sailor the feel and handling issues of a faster skiff, while not making the ride so zany that it becomes a real problem. The transition should be comfortable and a fairly simple adjustment for the young sailor.

Save for the slightly scaled-down spinnaker, this rig is pretty much the same setup that I have used on a multihull trainer I designed, the SOLO12. I’ll provide a separate posting for the three boats in the Solo Trimaran series in the very near future.

The mast for the breathed-on Cabrillo is stiffened with shrouds, as well as the forestay holding the spinnaker. There is also an option to include trap wires for the kid who wishes to take things to the next level.

I figure that this boat will need to have a skipper of right around 140 lbs. to handle the Turbo version of the boat in 14 knots of breeze. That opens the potential sailing audience to a pretty wide bunch of people. I was asked some time ago just how much could the boat handle in weight. The answer is that the Cabrillo has been designed with displacement figure of 250 lbs. Remove the boat’s all-up weight and you’ll pretty much max-out at just over 150 lbs. for the crew.

All in all, the project looks like it’s just about ready to crank out some plan sheets, and get rolling on the build process of the first boat. I’ll probably have the hull panels cut on a CNC machine. I plan to offer the boat as a pre-cut plywood kit, complete with fiberglass cloth and all the small bits necessary to put the boat together. The kit purchaser will need to get the required epoxy/hardener from a local, or mail order supplier, as well as the sailing hardware, ropes, aluminum mast sections and the specified sail.

Chris Ostlind

Lunada Design

A Skiff for Kids

lunadadesign — Thu, 16 Oct 2008 22:01:29 +0000

Kid Sized Performance

for the Homebuilder

Recently, a design brief appeared on the Dinghy Anarchy Forum pages of Sailing Anarchy. Within that first post, the following objective elements were shown: Dinghy Anarchy Thread

Kid’s Boat Design Brief

- Easily rightable by a 90-100 pound child – this also means it does NOT have to be keelboat stable
- Light enough to move around by a child (50-60 pounds hull weight)
- Big enough so he could take out a friend
- Simple to rig, sail and de-rig
- Fast enough to plane
- Unstayed mast
- “Cool” enough looking
- Self bailing, open transom, easy to enter from water
- Fun enough that he’ll let me sail my singlehand skiff by myself!
- Winter garage project
- Generally light wind venue with little real waves
- Don’t care about racing or an established class & society - my son’s a loner with no “pack animal” instincts (comes by it honestly)

I responded to this Brief by posting a couple of renderings for a small kid’s skiff which I had drawn-up some time earlier and had left on the shelf in favor of other projects. The Sailing Anarchy posting gave me a chance to unveil the new boat, but the story about its creation started much earlier…. much earlier.

The Beginnings of a Future Boat

Way back in the very late fifties, when I was just a fresh-faced Tenderfoot in the Boy Scouts, I learned to sail at the Sea Scout Base at Cabrillo Beach in San Pedro, CA, . The Base had a small fleet of Opti prams and an oddball collection of larger sailing boats that were used for sailing lessons, merit badge work and just plain old goofing around with my buddies in the enormous body of protected water known as the L.A. Harbor.

I was pretty much stoked to get my first shot at sailing alone after cruising around in a bigger boat with one of the parents, learning how things worked. The Optis weren’t such bad boats back then (Geez, they still aren’t bad boats) but recent rumblings in the boating world for kids have changed the harbor landscape quite a bit.

Enter the O’penBic dinghy for kids.

If you haven’t seen them, these little dudes are amazingly fun for the kids who are the right size. Basically, Bic (yeah, those Flick my Bic people) has taken the performance dinghy concept and brought it right down to the entry-level sailor with sailing simplicity, as well as a reasonably affordable price of just under $3K.

The result is the Cabrillo Dinghy after the location where I learned to sail way back in the day at the Sea Scout Base. You can build one with four sheets of plywood, a few yards of glass cloth, some epoxy, a small collection of sailing hardware, an aluminum tube and a nice sail that can be had direct from Duckworks on these pages.

This is a fairly simple, stitch and glue boat in 4mm marine ply with glass/epoxy laminates inside and out. It also has a fully boxed truss system under the deck to absorb all the loads and spread the weight of the sailor over a larger area. It has a main sheet, a tiller and a padded foot sling for hiking out. There is a daggerboard and a flip-up rudder and that’s pretty much the whole deal.

The boat is a sealed, hollow form, so it is essentially unsinkable. It should be very easy to right and it requires no bailing at all when jamming around under power, as all the water taken in will simply drain out through the open transom. Again, simple, painless and easy for kids to keep focused on the business of learning how to sail their own sport dinghy.

Construction wise, the Cabrillo is a bit more involved to build than is the wonderfully conceived, OZ Puddle Duck by Michael Storer, by way of Shorty Pen. The Cabrillo, however, is aimed at a different kind of audience who has something else in mind, even though the PD is a pretty cool little boat for a somewhat similar purpose.

Power for the boat comes from a square topped, 56 sq. ft. sail, mounted on a very affordable, two piece aluminum mast with a luff sleeve. A simple boom, main sheet system and then drop the whole thing into a pocket in the foredeck. The Cunningham mounts to the deck, so the mast stays with the boat when it is capsized. And it will be capsized… count on it.

The foils are very straightforward, NACA section shaped White Ash blades that get varnished after a coat, or two, of epoxy. The whole boat, once taken apart can be easily car topped on any compact car. For that matter, the Cabrillo will easily fit in the bed of a typical full sized pickup, along with the two piece mast and the rolled sail. Simple, painless sailing trips with your kid are right around the corner. The Cabrillo is designed for kids, or any person up to the 160-pound range. Obviously, the bigger the kid, the slower the boat, so there’ll be some fiddling and pestering, once your kid gets up in the weight limit region and is getting passed by younger kids.

I have only one bit of caution for the prospective builder of this boat. Start making plans to move up to the next bigger performance dinghy in your local area, because as soon as your child gets too big for the Cabrillo, they’ll be bugging you to build their next hotrod dinghy, or skiff. I’m working on that design solution right now.

Chris Ostlind

Lunada Design

After checking out the Bic at its introduction one summer, I decided that I just had to take a crack at drawing my take on one of these cool little boats for homebuilders. I saw the whole design as an opportunity for Dads and their kids to get in the garage and knock together their own sporty kid’s dinghy, so that they could go out and mix it up with the O’penBic boys and girls.