2010 Stock Outboard Class: Mini Formula 1

[Ron Hill]

With that 10 X 18 I sent, have you raised the motor? Truth is, when Bob Calrson built this boat we liked the cleaver, low rake as it didn't try to lift the bow...

200 RPM's down could be more than 2 mph.....

[SEASTALKER]

I would like to know more about the origins of the Bobcat and the motors that were used to power it. I believe this was back in the 1980's?

What speeds did they achieve in those days?

At the speeds this craft is running at there is very little aerodynamic lift and a prop that gives a degree of bow lift is fine.

We have experimented with jacking the motor and we find the best position is with the cavitation plate level with the tunnel.

We find the best performance at the moment is with the PowerTech SRA3 -
10x16 cupped.

The motor is basically a commercial fishing motor and is supposed to run in the 5200-5800 rpm range. It has a very flat power curve.

These motors in Zapcat racing regularly run at 6200rpm and appear to be unburstable.

Peter

[Ron Hill]

What I know about Bob Cat Tunnel Boats.: Bob Carlson, the son of Art Carlson of Glastron/Carlson fame (Builder of the Glastron Molinari Race Boats), worked for Art.

My numbers will be off so don't quote me. Art Carlson built some seriously cool boats in Garden Grove, California. The first boat he built was a tunnel and it would not plane, as the motor had no power trim and little power.

Seems Art then built Kenny Pyle a D Hydro. Painted it a beautiful metalic green... Boat wasn't very fast, but had some great design features like large chines.

By 1968 Art was building probably 5 pleasure boats a week. Why did I come up with five? Well, I used to visit his shop and he'd be adding finishing touches to boat halves in molds. He's spray a "splatter" finish to each boat before they were assembled.

Art liked metal flake...REDS, BLUES and GOLD....In '68 Glastron bought the rights to build Molinari Tunnel hulls, but didn't have the facilities to build Custom boats so they bought Art Carlson's business for like 5 million, in cash and stock. And gave Art a ten year job.

While Art was running Glastron Carlson, he hired his son Bob and Gary Ferguson to be designers. They both had and have a tons of design talent. After Gary left Glastron he worked for Advantage Boats in Havasu, until he ritred, recently, but they still use him for various projects.

Bob raced A Stock Hydro in a boat he built. A beautiful boat, that was too small and he turned it over frequently!

About this time, the Japanese wanted a COOL boat for their gambling curcuit. Bob built them a tunnel for the curcuit, and can be seen on the Yamato Outboards home page. Bob spun this boat off into a Sport C boat. Boat had done most , if not all, of his testing with a Yamato, but then he tested with a Mercury.

I had written the rules for Sport C to favor the Tohatsu's 40, as it was 31 cubic inches, Mercury's 40 was 44 cubic inches. And Mercury had turned their back on racing while Tohatsu paid our insurance, and bought our trophies.

Blake Esau from Las Vegas, bought a few Bob Cats and made them run very fast. Blake discovered that a Tohatsu could get water from the prop throwing water on the scoop behind the prop, not just from the side pick ups.

With an up and down transom controlled from the driver's seat, Blake could raise his propshaft to make it even with the tunnel top...he could go almost most 70 MPH, but could not turn, he'd lower the engine for the corners. After several major accidents, up and down transoms were ruled out.

Blake himself was never in an accident in a Sport C. He did break both shoulders in a 45 SS blow over that ended his racing, he would bring six Sport C's to the races. Blake bought Bob Carlson's molds and then built his on boats and made different molds.

The last time I saw Blake he still had more the 12 Bob Cats.

Bob Carlson and Art both live near or around Hemet, California. Gary Ferguson lives in Lake Havasu City. And I've been looking for Blake to buy his old Sleek Craft with a small block Mercrusier, that I know he still has, somewhere in Vegas.

[SEASTALKER]

I don't know if this is the same Bobcat as the Carlson Boat? I have attached a photo of the name plate and this shows the company based in Huntington Beach CA.

A question for Bob.

In GT-Pro you have no resttriction on the props. What props are competitors using to achieve 46/47mph?

Thanks for the info.

Peter

[Ron Hill]

Lamps "R" Us was in front of Unit I. Toys "R" Us made Lamps "R" Us change their name. It was changed to Lamps Plus.

That is the original location on Edinger in Huntington Beach.

[Chairman]

Peter,

Ron was kind enough to send us some props last spring. I ran one of them all summer. The one in the lower right is only 9" diameter (actually 8.875", I think) and was too small. The others are 10" or so diameter and 16" and 18" pitch. I ran an 18-pitch on my v-bottom and got about 6800 rpm.

(Note to Ron: I'll send the small one back to you one of these days so you can find it a good home.)



Also have had good performace with steel OMC props. Below is a 10x15 with a pretty aggressive cup. The 10x17 (no longer being made) with a normal cup performs about the same.

I'm hoping Ron will come up with a cleaver, about 10.5x17. I've also looked at those PowerTech props, but would like to see a bit more pitch.

[Ron Hill]

Working on several props, just BEHIND!

[marinetech51@earthlink.net]

Always thought the Bobcat and Tomcat were Mirage boats.

[Ron Hill]

Brad Callins the son of Louis Collins built the Mirage Boats. The Tom Cat, I think, was a Mirage Sport C. These boats were built in Texas. Miss BK her is Brad's wife.

The Bob Cat was the name of Ronnie Rima's D Runabout back in 1962. But Bob Carlson built the Bob Cats right here in SoCal.

[SEASTALKER]

I am a bit confused by the posts. Was the Bobcat, as my boat, built by Carlson and was it their shop at Huntington Beach. Has anybody got some photos going back to the days when whoever built the boats there.

On props, the best results we have so far is with the PowerTech SRA3R16 at 10"x16". Although they list only up to 15" pitch they do offer 16" pitch with this prop. The prop has a 20 degrees aft rake.

For me they produced one with standard cup and one with a more agressive cup.

The results as my earlier post show the speed was almost identical with both props, just the revs went down with the more aggressive cup. Anyhow we are getting about 10/11% slip and I doubt we are going to better that.

When we change to 50:1 oil mix we will get more revs and more speed, hopefully!

Peter