PRATHER LAP CAT 2 K&B 7.5 CC

[YOGI]

I AM TRYING TO FIND OUT A GOOD STARTING POINT FOR THE ADJUSTABLE MOTOR MOUNT MOUNTING TO TRANSOM. WHERE SHOULD THE PROP LINE BE IN RELATION TO THE BOTTOM OF THE TUNNELL? ALSO WHAT IS A GOOD LINKAGE TO USE FOR THE STEERING? I DON'T LIKE THE SLOP IN THE CABLES.

 

[mikeferretti]

I AM TRYING TO FIND OUT A GOOD STARTING POINT FOR THE ADJUSTABLE MOTOR MOUNT MOUNTING TO TRANSOM. WHERE SHOULD THE PROP LINE BE IN RELATION TO THE BOTTOM OF THE TUNNELL? ALSO WHAT IS A GOOD LINKAGE TO USE FOR THE STEERING? I DON'T LIKE THE SLOP IN THE CABLES.

Yogi, there is nothing wrong with using cables as long as they are tight, with a capitol T. A prather lap Cat II is what I started with 20 years ago. With the 7.5 C.C. Outboard there are a lot of forces generated. Water is 100 times denser that air. Your steering servo needs to be Securely mounted. Another way to go would be High Quality 4-40 Pushrods from the servo to the motor. You can put what ever bends you want in them to get back to the motor. Keep the bends shallow. 30 degree bends are better than 45 etc. will flex somewhat less. If you want tighter steering then also want to go with a 5 cell receiver battery. Vast improvement on steering response! Also in my humble opinion you must use a high torque servo rated at At Least 100 ounces!

In tower hobbies advanced search just now. 3305 futaba servo rated at 124 Oz at 6 volts. $35. The middle of your prop shaft should be right in line with the bottom of the rear of the hull. "Surface Drive" is supposed to mean that only the bottom of the prop is pushing the water, or in other words one blade at a time.

T.T.F.N.

M.F.

 

[YOGI]

THANK YOU VERY MUCH FOR THE INFO.

I ORDERED A HI TECH 1/4 SCALE SERVO. THIS IS AN OLD HULL THAT I'M RESTORING. I RAN IT 1 DAY AND QUICKLY REALISED THAT THE STEERING NEEDED TO BE TIGHTENED UP. WHEN YOU GET ON THE PIPE IT WOULD NOT STEER AND WOULD DART LEFT OR RIGHT. I'M ASSUMING THAT IT WAS THE CABLES FLEXING OR THE STANDARD SERVO NOT HOLDING TRUE. BUT WITH HELP FROM PEOPLE LIKE YOU I WILL GET IT GOING.

THANKS AGAIN

 

[mikeferretti]

THANK YOU VERY MUCH FOR THE INFO. I ORDERED A HI TECH 1/4 SCALE SERVO. THIS IS AN OLD HULL THAT I'M RESTORING. I RAN IT 1 DAY AND QUICKLY REALISED THAT THE STEERING NEEDED TO BE TIGHTENED UP. WHEN YOU GET ON THE PIPE IT WOULD NOT STEER AND WOULD DART LEFT OR RIGHT. I'M ASSUMING THAT IT WAS THE CABLES FLEXING OR THE STANDARD SERVO NOT HOLDING TRUE. BUT WITH HELP FROM PEOPLE LIKE YOU I WILL GET IT GOING.

THANKS AGAIN

Yes, it was almost for sure your servo. That HiTech servo should provide many years of good accurate tight steering!!! Good Choice! Are you using a "Solid" motor mount, or a "Kick Up" that lets the motor pop up if you strike something in the water like a fish, stick, beer bootle, turtle, etc. I don't there are any of this type being made any more any way... I recommend you reinforce the ends of the two servo rails that your steering servo will be mounting to at where they attach to your radio box, with either 1/16 plywood plates surrounding the ends of the rails, and, or screws driven in from the outside into the rails. I reccomend both. If you were to try a "Kick up" type motor mount, they are hard to get the steering cables tight, because then they just want to lift up the motor. Also during a race if you throttle back fast the motor will lift instead of slowing down the boat immediately. I recommend a solid motor mount, The only advantage to a "Kick Up" is they sometimes can help Reduce the damage to your boat if you strike something in the water...... Like I said i don't think there are being made any more any way...........

 

[YOGI]

I'M RUNNING THE ADJUSTABLE MOTOR MOUNT LOOKS TO BE DUBRO OR OCTURA NOT SURE WHICH. I'LL PROBABLY STICK WITH IT FOR NOW. I JUST PURCHASED A BULLET DRIVE LOWER END AND NOW I'M RESEARCHING PIPES. ANY SUGGESTIONS? THE SILVER BULLET PIPE SOUNDS LIKE THE ONE. LOOKS LIKE I WILL HAVE TO MAKE A HEADER FOR THE K&B MOTOR HAVEN'T FOUND ONE YET.

 

[x120leecraft]

Yogi I beleive you can get the header & silver bullet pipe from Mark Hopper @ HTB Boats.Com

 

[YOGI]

THANK YOU I WILL GIVE HIM A TRY