I've only seen one Cat at a RR race in person but unfortunately my cameraman was more interested in something else besides taking pictures and we didn't end up with one of this boat. Don't know if you would want to copy it as it did not do so well due to trying to nose over when raced. It was adult built (Leader) out of only one RR Kit plus I think two popsicle sticks. I think he had the sail/mast too far forwards.
Torpedo design? I think that you will find on the Lastufka site that you want to build a planing type hull and not a displacement type hull - you want it to get up on plane and run across the top of the water and not through it.
I think that the bow pitching up is preferred having worked around Bass boats for 20+ years. They are basically speed boats with trolling motors (though I've never caught a fish while running 70+ mph...) and are shaped to get 'up on plane' as quickly as possible.
If you can get the boat to plane out I don't think that side bumping is a concern. At least it wasn't on the boat I raced some 3 - 4 years back (I could generate more wind back than!
We use 5 minute epoxy but only needed to attach the mast, rudder and keel. I think the guy that built the Cat used white glue or possible a wood glue but it was sealed with paint and so did not come apart.
Sail Design - we are restricted to the RR Kit as our non-Cubs race under the same rules as the Cub Scouts do. However, I would think that you want the sail as low as possible so as not to make the boat any more top heavy than it has to be. This may factor into your material and shape choices as well. We had a Cub Scout show up this year that had put glitter everywhere including the sail. After two runs, we got him to switch his sail out for a plain plastic one from a new kit. Before all it would do is keel over; with the undecorated sail he actually did quite well as it would remain upright.
Pointy nose? The stock RR Kit hull is pointy but I don't think that this is the best design. If it were flat and angled as to pitch the bow upwards the boat should get on plane that much faster and with less effort. Once up on plane the boat will be guided by the direction of wind blowing it, the keel/rudder and the sides of the raingutter - so who needs a pointy nose or a pointy centerline on the bottom of the hull?
We try and put as much weight rearwards as possible, so the mast gets moved back to about an inch - inch and a half from the rear. Wait a minute: that weight placement deal sounds somehow familiar...
Replacement for balsa - We are stuck with the kit but I think you would only find something like plastic would be as light and as strong as balsa. Hmmm, thermoformed RR boat hulls...
Straws - Our Pack supplies the straws for our races. This was done because some were showing up with larger diameter straws than others which may be an advantage or not. I will warn you about the straws with the bend in them: the ones we found cracked at the bend joint after minimal usage. I'm sure the boys had flexed them quite a bit before and after their races and this only added to the number of straw failures. We use straight straws now because of this.
Water depth? We fill our PVC Pipe "raingutters" to the brim!
No timing - all heats are judged by someone on each side of the finish line. The first boat to touch the end is the winner. We used flags this year to help indicate which boat won. This kept the record keeper from having to hear the finish line judges over the laughter and cheers. Since we have one Blue and one Gold (okay, its really yellow...) raingutter/PVC pipe; each finish line judge had one blue and one yellow flag. It would have worked perfectly too it that big oaf of a judge we had would have raised the correct flag (name withheld because he is typing this message
). Both finish line judges raised the color flag corresponding to the lane that won. If both did not agree; we first made sure that I raised the correct color flag
, and if they still did not agree the boys re-ran that heat.
Da Graphite Kid