7/29/02
Once again last year's Sidewinder Hydrobowl performance was not as impressive as I would have liked. I'm not sure what to blame it on this time (it couldn't have been the rider!), but it may be that the Bolly Prop is not optimized for HPB use. This year I will be using George Tatum's Heron HPB prop. George spent a significant amount of time modeling and testing this prop and I'm confident that it will show in it's performance. The Sidewider will remain in it's current configuration once again this year, with some minor work being done to change to a 1/2" drive shaft which supports the Heron prop, and to strengthen the U-joint. Last year's single race was practically enough to destroy the old U-joint.

Once the drivetrain modifications are done, I will move the rudder to the front of the boat to improve the maneuverability. It appears that in a catamaran HPB, the rudder must be placed at some distance from the prop. Also I had been using a flag shaped rudder, and will move to a dagger shaped rudder if time allows. 

I'm starting to think about the new twisted chain drivetrain again. I found that if you loosen the pins on a standard derailleur bike chain, that it will twist in a relatively short distance, about 1.5 feet. That's about half the distance of the twisted chain drive on the old Hammerhead HPB.

8/13/02
I replaced the old U-joint with a slightly larger McMaster-Carr pin and block U-joint, fitted the Heron prop to my drivetrain, adjusted the drive ratio to 2.7 to 1 for the big 20 inch prop, and installed the new rudder in front.

This year the IHPVA World HPV Championships were in Brantford, Ontario, which is within driving distance of the Chicago area. As I was going to race my bike there anyway, I took the boat to participate in the HPB competition. After some confusion, it was decided by the HPB racing officials to hold the races in an all but inaccessible portion of the murky, weedy river that runs through Brantford. The 9:00 am races were finally started at about 2:00 pm due to logistics and setup problems. I quickly discovered that my new rudder was still ineffectual due to bending in the relatively thin aluminum rudder blade.	Garrie Hill helps to put the Sidewinder together
Racing at the World Championships	The new Heron prop felt great though and ran very strong between stopping to clean the weeds off the blades. I did a bit better than last year, and posted a 30.5 second 200 meter sprint, up stream. In the 2K race I passed everyone but George Tatum (who lapped me) on the WaveBike GlassFeather, but I was not told about a change to the 2K TT rules, so I sprinted for what I thought was the finish and then stopped racing a lap early and was re-passed. The slalom was tough as once again the boat did not turn well.
Part of the problem was that the rudder was bending massively, and part of the problem was that the front end of the outside hull would submerge in the turn. One strike for minimal floatation hulls... Once again nothing broke on the boat while I was racing, but the drivetrain was damaged while a certain hammerhead was test riding it after the races. I'll need to reinforce the rudder and fix the drivetrain before the September 7th WISIL Hydrobowl races.	Racing at the World Championships (click for the big picture)

 9/20/02
The WISIL Hyrobowl was fun, and the boat performed quite well in a straight line, but still had turning problems. I used a bigger, thicker sheet of aluminum as the rudder, and it was still bending in the turns, so it looks like I need to build a carbon fiber rudder for next year. I did my fastest ever 100 meter sprint at just over 26 seconds, thanks to George's big prop. According to the HPB calculator page, the hull speed for my 12 foot long hulls is 5.4MPH. I averaged about 8.5MPH in the 100 meter sprint. Wow, that's 157% of hull speed! If I can get a 20ft hull to do the same thing, that's almost 11MPH! This seems quite possible, as that's what George's Wavebike did when he did a 20 second 100 meter sprint.

I'm starting to think more about a monohull HPB. It should be faster due to it's increased overall length, and if I make it narrow enough, it's wetted area should stay low. I did some doodling in a meeting and came up with the basic configuration below. You can click on the drawing for higher resolution.
This design utilizes a hull length of about 20 feet (7MPH hull speed). As I am planning to sit as low in the hull as possible for maximum stability, the max width will need to be at least 15 inches. It will use a compact twisted chain drive system, as well as an active canard balance fin.
The section of the fin that fairs the drive system will be fixed, and only the section of the canard fin under the drivetrain will be moveable. The canard will be controlled by a handle mounted to the left side of the hull, and the rudder by a handle on the right. I'm not planning on water legs, as I'm hoping it will be inherently stable enough to allow me to get in and out without dumping it. The deck of the HPB will be raised to act as a fairing and to shed any splashed water. There will be fore and aft compartments (aft is "water tight"), but areas in front of and behind the compartments will be solid foam so there is no chance of sinking. Does it look like a recumbent wavebike? Hmm...