9/04/03
Last year's Sidewinder Hydrobowl performance was better than the year before, largely due to George Tatum's Heron HPB prop. George spent a significant amount of time modeling and testing this prop and it shows in it's performance. The major weakness in the Sidewinders performance last year (apart for the diminutive 12 foot hull length) was once again it's turning ability. At last year's Hydrobowl, the rudder, which was constructed from aluminum sheet metal less that 1/8" thick, would bend violently in the turns, and cause the tips of my hulls to submerge. This meant I lost ground on every corner. This is where my shorter boat should really scoot, and the longer boats should drop behind. I was barely able to maneuver through the slalom course!

It appears that the large bladed prop support (which is shaped remarkable like a rudder), makes the boat always want to go straight (funny thing, that!). I had used it before and had the same problem. This year I'm removing that support, and making a new one from narrow aluminum straps. Also I'm re-making the rudder, and moving it to the back again. I only have 2 more evenings to remake the rudder supports, and no time for testing before the Hydrobowl 2003 races this weekend!

9/15/2003
The Hydrobowl 2003 races have come and gone. The good news is, the boat worked extremely well and I won most of the races!   Hydrobowl 2003 pictures.   Hydrobowl 2003 results.

Here's a picture of the business end of the reconstructed  Sidewinder, resting on the shore at the Hydrobowl races. Shown are the new prop stays, and the new rudder. This configuration allowed the boat to turn very nicely. I could have probably even have gotten away with a smaller rudder with less drag.  Interestingly, even though I won races, my sprint and 2K times were no faster than last year.

Here I am on the Sidewinder, cruising through the Slalom. Only about 1" of the hulls is above water.  Since my 100 meter sprint speed was about 8MPH and hull speed for these 12 foot hulls is only 5.38 MPH,  I suspect that this is about as fast as this boat will get with these hulls. This calculated hull speed seems to be pretty accurate, as my 2K crit average speed was 5.27 MPH.  I think the hat slowed me down...

Though my ultimate goal is to slam a twisted chain drive and a comfy seat into a nice fast sea kayak, I'll probably just be tweaking this design a bit more for next year. It's pretty close to dialed in right now. Maybe I'll just change it so I can sit facing forward...