The PerformanceBoats.com thread about our participation at the Oroville (CA) Time Trials sparked some requests for more info about Comp Jet circle racing in general and the event in particular, so here is more detailed coverage.
The 2013 Oroville Time Trials, hosted by the East Bay Boat Club of APBA region 11 took place on the weekend of 3/16 & 3/17. Before I get into the action, let me say thanks to all the EBBC officials for their friendliness and hospitality – race director Dan Wilde, referee Bill Boyes, scorer Jean Mackay, surveyor Russ Dodge, inspector Bill Thompson and the rest of the crew including the Rescue folks, who reminded us often “not to get wet”.
Circle boats have records for two different types of accomplishments. First is a Five Mile Competition Record for the boat (in each class) that completes a 5 mile race with the highest average speed on a surveyed oval course. The second is for the boat that averages the highest speed over a surveyed straight line course, either one Kilometer in length (approx 3278 ft) or one quarter mile (1320 ft). Both straight line courses use a flying start.
The Oroville Kilo and Quarter mile courses were laid out on the Thermalito Afterbay below Oroville Lake, very close to the dam and parallel to highway 99. The course looked something like this – two entry buoys at 3300 ft before the start timer, two “get after it” buoys at 1500 ft before the start timer, two more buoys at the start of the time traps, two buoys at the end of the Qmile and two buoys at the end of the Kilo. The first two sets of buoys were repeated at the far end of the Kilo because each racer, upon reaching the far end of the course had to turn around and make a 2nd run through the course from the opposite direction. The times for the two opposite runs were averaged together for a final result.
Boat racers usually go to a time trial because they think they have a shot at their class record. The current Comp Jet Kilo record stood at about 98 mph, although before the class died out around the early 90’s, the record was about 111. Our CJ123 team decided to go after the current record without any thought of bettering the old record.
APBA rules require a boat to “qualify” for a time trial event by finishing third or better in a circle race within the previous 12 months. Of course every boat must remain class legal at a time trial but there is no requirement that you use the same engine or boat setup. At a circle race event boats are setup for engine reliability, traction in the choppy water, best cornering speed, etc. At a time trial all that goes out the window and maximum straight line speed takes priority. Racers are known to remove all unnecessary weight from their boats and change to more drag race oriented engines. Prop boat guys bring boxes of props and Jet guys bring boxes of straight line hardware (shoes, nozzles, loaders, etc).
We swapped driver Tom Bandy’s “easy chair” seat for the light-weight bucket from his drag boat and headed for Oroville with no other changes from our last circle race. Once at the pits we decided our setup was too conservative, so we put the ride plate up one more degree.
The order for running was determined by a drawing at the Friday evening driver’s meeting. Tom drew #1, which was good for the early morning cool air, but bad for a Kilo rookie who had never seen a Kilo course layout. The course was a ½ mile run from the pits and Tom got his bearings right away when he saw the 3300 ft markers. We could not see much of the course from the pits due to several islands that blocked our view, and the boat was so far away that it appeared very small. It was kind of nerve wracking waiting for the boat to come back into view on the return run. The race director was always by the launch ramp dock with radio communications to the scorers on the course and a red flag in hand that was waved to signal a record broken.
When Tom came into view and headed back to the pits, the red flag waved and the official announced 106 mph. We were all pretty surprised! As soon as the boat came out of the water the inspectors were there to take a fuel sample and put sealing paint on the engine, mounts and rudder.
We had a rough game plan for the event, so back in our pits we took off all our circle hardware and bolted up a full set of drag-race stuff. Not having run this setup before, we kept the adjustments on the conservative side. Also being conservative, we elected to run the Qmile next in order to see how the boat would react. The setup was ok and the run was 108.145 mph, a new Qmile record for Comp Jet. Again the inspectors took a fuel sample and checked the seal paint.
Next we adjusted the hardware to fly the boat a little more and headed back to the Kilo. This run was about mid day but the speed went up again to 109. The official said one leg was 110 and the other in the 109’s. (More inspector eyes back in the pits). Encouraged by that result, we changed the hardware again and went out for our last Kilo of the day.
No red flags this time! Tom came in and said the southbound run was fast but the northbound speed fell off during the run. The motor checked out ok but an inspection of the jet located a 6 inch twig lodged in the impeller.
We knew the inspectors were going to tear our engine down on Sunday so we decided to max out our jet setup and take one more Kilo run on Sunday morning while the air was cool. When Tom went out for this last run, we could see from the pits that the boat was really “truckin”. He had the cav plates up until he could feel the boat skating around like a fast drag boat, and he has a lot of experience at that. Then the official waved the red flag, announced 113.323 mph average and said that even the scorers had cheered. Boy did that suddenly make a thousand miles of driving seem worth it.
Back in the pits, our engine guy, Dave Ebbert, went to work removing a cylinder head while the inspectors measured the hull and rudder, took fuel samples and check other class requirements. The displacement check was quite safely under the class limit of 515 cu in. and the inspectors signed off on the APBA record paperwork.
For those of you who have never seen a Comp Jet circle boat, here is a rundown of the equipment we use.
Hull – 1976 19ft Liberty V-bottom with bottom mods by MPD and Kornowski’s Kustom Marine of Lake Havasu City, AZ. Rigging and cav plates are by MPD. Calgo steering is offset about 12 inches to the left. The fiberglass is maintained by Kornowski’s and the bare hull weight exceeds 600 lbs. Styrofoam flotation fills the entire under-deck area.
Jet – Berkeley split bowl pump with AQ shaft & SS impeller mounted on a Bayjet intake. The steering nozzle is a highly modified Place Diverter that is not adjustable while underway and turns in a Place Hi Perf Nozzle Housing. All blueprinting and hardware are by MPD. Data is collected from the jet with an Edelbrock QwikData system.
Engine – 510 cu in iron block BBC by DNE Motorsports. Aluminum heads & cast manifold are by Edelbrock and have common wall intake ports as required by the class rules. The headers and EFI induction are also by Edelbrock. Some engine functions are monitored by the QwikData system. Lucas Racing Oil provides the lubrication, and tuning is done on the Westech Dyno.
Crew – Our crew chief is Brad McComb. The launch truck is usually driven by Jennifer McComb or Susie McClure. Pit help comes from Chrysteen Bandy and occasional crew helpers have included Mike Flanigan, Lance Oster, Mark Roznos, Chris Austin and Bob Prigmore. Thanks to all!
Jack McClure
Comp Jet 123
