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Building the CubCat from the Cub Scout Regatta Kit


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Safety!
Hull
Sail
Finishing Touches
Other Tips
Copyright

  Safety First!

Unlike the standard design, building this boat requires making cuts through the kit's balsa hull block, and more extensive gluing.  Scouts must not attempt this project unsupervised!  This document is intended only to outline the work required to build the boat, not to teach safe workshop practice. Power tools aren't necessary for this project, and I recommend that they NOT be used because of the small size of these parts. Handle and use sharp hand tools carefully, and be careful to avoid burns from hot glue and glue guns, if used.  It's your (Akela's) responsibility to know how to use your tools safely, and to ensure safety throughout construction!  If, for any reason, you're not completely confident that you and your scout can safely complete this project, please don't try! Building a toy boat is far less important than your safety!  

Hull

  1. Make the ponoons.  Before making any cuts, lay all of them out and mark the hull.  The first cut is made down the center of the hull, and makes the two pontoons.  Use a small handsaw (hacksaw, coping saw, hand miter saw, etc.) for these, and be careful to hold the block securely.  The rounded "sides" of the original block become the bottom of the pontoons (facing down into the water) and the centerline cut (that you're now making) forms the top of the pontoons.   My Wolf scout was able to do this himself with a saw with some supervision; my Webelos did it with minimal supervision. Here's a sketch of the three hull cuts: sketch of raingutter regatta hull cut layout
  2. Make the spars.  Use the saw to trim off the rounded "sides" of the original hull (bottom of the pontoons, cuts #2 and #3 above) so that they become flat.  The pieces removed should have a maximum thickness of about 0.1-0.15", making them suitable for "spars" to tie the two pontoons together.  Do this carefully to make the two pontoons nearly equal in size/shape.  Scouts can do the cutting, but will probably need help in laying out the cut lines and starting the cut.  Any inconsistencies between the pontoons can be cleaned up by sanding later.  If you want to use material other than the hull block for spars, this step can be skipped, but the flat-bottomed pontoons made by these cuts run faster.
  3. Sand the pontoons.  Have the scout sand the two pontoons to make them equal height and straight and smooth on the "top" (centerline cut) surfaces.  Holding the pontoons together while sanding with a foam sanding block works well.  Wetted edges of the pontoons can be rounded slightly, but the bottoms should remain flat.  (I firmly believe that sanding is a character-building task which all scouts should master. ;-)
  4. Assemble the hull.  The "slivers" cut off the pontoon bottoms, pieces of mast, or other material are used as spars to tie the pontoons together.  Lay this out and glue the pontoons and spars together, being careful to keep everything square. We use hotmelt glue, but any waterproof wood glue should work as well.  If your pack or district restricts the boat's width (beam), be careful to satisfy this requirement.   (Sand the sides of the pontoons, if necessary, and make an allowance for paint thickness.)   If beam is not restricted, I recommend making the outside edges of the pontoons about 2-1/8" apart.  This is wide enough for very good stability, but not so wide that the boat will bump the sides of the gutter excessively.  Note that the mastless sail design described below won't work if the pontoons are too far apart!  I also recommend using the hull "slivers" as the spars, with the forward edge of one spar at the mast hole cutout, and the aft edge of the other spar at the stern of the boat.  These two locations provide good mounting points for the sail and rudder, respectively.
  5. Sand the assembled hull.  Trim overhanging ends of the spars even with the edges of the hull, and sand the assembled hull for painting (being careful to keep the pontoon bottoms flat).  For the wetted parts of the hull, smoother is faster.
  6. Add mast(s), if desired or required.  The mast isn't necessary, though, and a mastless design with the sail described below will perform better.
  7. Decorate before painting.  Add decking, decals, or other decorations as desired and allowed by local rules.
  8. Seal and paint the hull.  We used sanding sealer/model paint.  Good waterproofing is important to keep the boat from getting heavier during the races from water absorption.  

Sail

  1. Trim the sail.  Cut off the top of the sail with a cut just below the upper mast hole (include the upper mast hole in the part you cut off).  The top part of the sail doesn't help much in propelling the boat, but its weight contributes a lot to "top heaviness".  Regular scissors will do the job. (I think that cutting even lower might improve performance further if the scout has good blowing technique, but we didn't try it.) regatta catamaran sail trimming sketch
  2. Add a spar to the sail, if desired.  A small shaving from the mast or a piece of balsa scrap can be glued to the rear top edge of the sail as a spar or stiffener to hold the top of the sail open (see photos of "Packers" boats above from the rear).  If using hotmelt, apply it to the wood first, since the hot glue can melt the sail.  Applying an ice cube or wet rag to the sail immediately after placing it on hot glue will minimize any softening or melting.
  3. Paint or color the sail as desired.  The bottom mast hole isn't needed, and can either be left open or covered with tape or a decal.
  4. Mount the bottom center of the sail to the hull.  For the sail design shown on the boats here, start by carefully gluing the center part of the bottom of the sail to the forward edge of the front hull spar.  If you use hotmelt glue, apply it to the spar first, then stick the sail to it.  (I suppose that small staples would work for attaching the sail, too.)  Be careful to keep the centerline of the sail true to vertical and centered.  Carefully trimming the center bottom of the sail to a be a straight line before gluing will help this.   With hot glue, use the ice cube/wet rag trick mentioned above to help it set up faster and minimize any softening or melting of the plastic.
  5. Attach the sail corners to the hull.  Once the bottom center of the sail is attached, bend the bottom corners around the sides of the hull to form the "cupped" shape shown in the pictures.  Leaning the sail backward somewhat (as shown in the pictures) helps performance.  Adjust the sides to a position you like, and mark the sail and boat so that you can reposition each side properly while gluing.   Glue the bottom corners of the sail to the sides of the hull in the positions marked.  Apply glue to the hull first, then stick the sail to it.

Finishing Touches

  1. Mount the rudder.  Use a small saw or hobby knife to make a cut in the aft spar between pontoons for the rudder.  Trim the rudder with scissors and mount it "long edge down" as shown in the photos.  If your cut isn't perfectly straight, don't worry about it--you can bend the rudder to the right location.  The boat can jump over its own bow wave on a good blow (yes, it will get "on plane"), and the deep rudder helps keep it going straight ahead when that happens!
  2. Attach the keel (only if required by local rules).  Don't use the keel unless local rules require it.  It isn't necessary for stability on this hull.  We haven't had to install one yet, but I'd suggest gluing it on top of the pontoons (out of the water) toward the aft end of the boat if you must have it.  If you run with a keel, I'd appreciate a note on what you did and how it worked.
  3. Decorate the boat.  Finish decorating the boat with decals, rigging, etc.    See tips below on how we made decals on the computer from digital photos and art work.
  4. Apply final paint.  A coat of clear gloss or "glosscoat" paint over the finished boat is good waterproofing, protects decals and decorations, and looks nice.

Other Tips...

For decorations we've used digital photos and other computer artwork to make decals.  Just put all the images in a single page Word document.  Images can be copied and scaled there to create similar decals of different sizes.  Test print this page on plain paper to make sure it's right, then print onto a sheet of adhesive inkjet label paper (available at any good office supply store) to make the decals.  The scouts can cut them out and stick them anywhere on the boat or sail.  As mentioned above, a coat of clear gloss model paint over the entire boat including decals provides good waterproofing and smudge protection.

Letting the scout practice with his regatta boat (of any design) is valuable!  The biggest difference between Regatta and Pinewood Derby or Space Derby is that the scout is an integral part of the race, and his performance largely determines the outcome.  Any problems with the boat setup or blowing technique can be found and corrected in just a few practice runs, and will help him feel much more confident at race time.  Bend the rudder slightly to the left or right to correct any "tracking" problems.  We don't have an actual raingutter course at home, but have used a water-filled plastic toboggan on a picnic table as a "test track".  Be creative!  Some things to look for in practice:
  1. Many scouts tend to blow "down" onto the boat at first, rather than "ahead".  They need to be taught to focus on a point on the sail as a target, and to concentrate on blowing "along" the course, rather than "down" into the water.  
  2. Sometimes there's a tendency to get too close to the boat, which can cause it to be blown over, or lead to contact between the scout's face and the boat (some local rules make any contact with the boat a DQ), so remind them not to get too close.
  3. With the CubCat, they'll have to learn to do these things while walking quickly, since the boat really moves down the course!
  4. Remember, the scout's performance is essential to the race--the boat won't get there by itself!  As good as this design is, it has lost heats to "standard" boats, usually because the skipper paid more attention to his opponent than to his boat.

Copyright

The designs and boats shown here are original works by my sons and me.  This material is made available for personal, noncommercial use only.  While personal use and web links to these pages are welcome, redistribution or sale of this material in any form is prohibited without express written permission from the author.  Sports team and product logos used in boat decorations are owned by their owners (not me).  Other than such logos, all material on these pages copyright © 2002 by Carl Schott , all rights reserved.