Aeromarine Sprint Cat 90

[BradV]

Hi guys

New to this forum but been into the 7.5cc mono scene over here in West Australia for the last 20 years. Currently running a pretty quick Skuai (an old design that was Euro World speed record holder in 71-75), don't know if any of you have heard of it?

It's currently running an OS 46VRM that's been opened up a lot in timing to get it to work like it should.... So far holding together with 50% nitro..., a very short pipe and a bit underpropped to keep it from prop walking.. Reckon I would hold the world record for getting one of these motors to rev and last! LOL

Anyway, just placed my order for an Aeromarine SprintCat and CMB 1.0 cube motor with Speedmaster running gear, should be here in the next 5 days. Looking forward to the upgrade.

Anyone out there got anything to say good or bad about that combo? Not a lot of people over here in West Australia running the glow boats anymore, shame about that, so I did most of my research from the internet. Also any specific issues anyone has found with strut angles, boat weight bias etc would be very much appreciated.

Hope the waters are smooth for you wherever you are on this great planet of ours..

 

[Don Ferrette]

Awesome combo. & tons of fun. I just finished building a new 42" Sprintcat w/ CMB 90 to run "open cat" class. Set hull on flat surface, drop strut down to set flat on same surface & tighten it down. 99% on the time this is on the mark. Set your CG between 31 & 33%. I run my fuel tank under the deck ouside the engine rail (right side viewed from transom) so CG doesn't change as you run low on fuel. This can help keep it from getting light in the nose & blowing over. I love my riggers for the speed but the cats are a blast, kind of like comparing Indy to NASCAR, ya gotta trade paint sometimes!

 

[BradV]

Don thanks for that, is the difference in boat speed between the riggers and cats huge or is it somewhat close?

With your advice of CG 31-33% pardon my ignorance, but is this worked out by 31-33% x length so the balance point on this cat @ 42 inch will be approx at the 13-14 inch mark from back of transom?

 

[Don Ferrette]

Don thanks for that, is the difference in boat speed between the riggers and cats huge or is it somewhat close?
With your advice of CG 31-33% pardon my ignorance, but is this worked out by 31-33% x length so the balance point on this cat @ 42 inch will be approx at the 13-14 inch mark from back of transom?

Cats vs. riggers? well let's just say my cat will run 65+ mph, maybe 70 on a real good day with ideal water. I'll heat race my newest twin rigger at high 80's low 90's.

But the cats are alot of fun & you can go hull to hull with them unlike a rigger if you touch anything it's over. Hence the Indy & NASCAR comparision.

And yes you did the math right. B)

 

[GTR]

Hi Brad,

I know about Skuai's - great boat. Designed By Giorgio Merlotti out of Italy - multiple time world champion. What a lot of people don't realise is that these little hulls were powered with anything from a 21 for multi racing to a Rossi 90 for Naviga triangle, mind you the tuned pipes were as long as the boats overall length. Plus you needed 4" long trim tabs to keep it stable - funny things is they never blew over but could barrel roll if you got it wrong. Very funny to watch.

Have fun with the big Sprint Cat - you could always stick a Zenoah in it?

GT (in the National Capital)

 

[akilbar]

I ran a Sprint Cat with a CMB 90 for a couple years. What a fun boat to drive, point and shoot. With the Speedmaster stuff, you'll be fine, I fought the Aeromarine rudder until I got it right. Don is right on with driving it versus a rigger, it's a blast to bump side by side.

Mine ran low 60's with the 90 ( old black case gold head) bone stock. The ABC M90 and M91 worked really well. I ran twin plastic tanks, one in front of the motor and the other outside the right stringer. It was fun as the fuel load dropped, the front would dance a bit. Actually it was rare that it would lift, I can only remember a couple blow overs.

I still have the bat and plan on Zenoah for it soon. Got enough nitro boats, wanted to try to mix it up with Gas.

 

[BradV]

I had a great race with a Zenoah Gas Engined SprintCat last year against my Skuai, it was one of the times when the Skuai went it's best. Believe it I actually beat him on the straight aways but couldn't match him lap for lap with his ability to stay consistent and corner flat out.. Maybe he was way off tune!!

The name of my multi is 'Unstable' and I can attest to the amusing aerobatics that's possible with these boats.. LOL Had more blow overs, roll over's and submarine dives than I can count.

Don 65+ mph will keep me amused, just waiting on the post man any day now..

 

[Don Ferrette]

Keep in mind at 65 she's gettin' loose but hey that's what it's all about right?