" One of the greatest secrets of boat racing is having a perfectly set up boat - Speed and Handling" DT Jr.

In recent years Doug Twaits Cyclone Marine riggers have been increasingly successful culminating in the Twister rigger wining 8, 12 and 18 cell rigger classes at the 1999 NAMBA Nats.

The 8 and 12 cell Twister Hulls weigh in at around 200gm. The 8 cell hull is built of wood -(ply & balsa), foam and carbon fiber. This article looks at basic set ups which will get it on the water and running fast.

Dougie and Doug Sr. provided many comments during the setup of the hull and they have been distilled here (with my comments or variations shown in brackets)

PAINT

Starting at the front of the boat - The best protection for the foam sponson is to skin them with thinned down some epoxy. Not too much - just enough to seal them foam.

First use a test piece of foam to make sure your thinner doesn't eat the foam. Assume all paint eats the bare foam!

After that is dry you can paint (or skin it with contact) the sponson safely.

MOTOR

"I suggest having a good hand wound ferrite motor to start. I recommend a 13/1 armature with the advance set to draw 4.9 amps at 5 volts." (this setup screams!)

(Use hard copper or polarized brushes and purple/13oz springs. We later switched to a ND10 neodymium motor - on the instructions of the designer I run 22 degrees advance - and a 10 turn arm - no problems no extra heat and good comm wear)

"Water-cool the brush hoods and can. Place the water-pickup on the inside edge and 1/8" forward of the trailing edge of the sponson, protruding by no more than 1/32." (Run the tube close along the rear of the sponson boom to avoid drag.)

"Turn the commutator and replace brushes every three runs to keep the motor in top condition. 8 cells are tough on motors." (I've run 5 packs)

A speed controller - Dougie uses Andy Kunz’s MC-2.

(I’m using a Hughey 3 speed (E1003) which has proven very effective. One tip - mount the speed control rigid and the servo on rubber grommets so that any additional servo throw is absorbed by the mounts, rather than stripping the servo gears.)

MOTOR POSITION

"Mount the motor on the center line of the hull."

"The guys in California were running the motors in my boats in the rear 7 inches from the transom. If you are going to put your motor in the back allow enough room to move your batteries forward and back but not to short on the cable in case it binds. If cable is short don't use an S bend."

(ultimately I mounted the motor 8" from the transom and use a 1/8" Hughey flex shaft. This helps centralize the mass immediately in front the motor and puts the cog at 15% of the after plane - a fast and smooth setup.)

RECEIVER AND SERVOS

"Use a FM transmitter and micro receiver. Keep it light - got to get that tail out!"

(I use a Hitec or JR am receiver, Hitec HS80MG servo for steering and a Hitec HS60 servo for the Hughey throttle.)

BATTERIES

"Use Sanyo 2000's and small receiver pack - 50mah - 270mah."

(I've used Hilltop NiMH, DR matched and zapped 2000’s and DR1250 mah for the motor and any of them will run five laps - however the lighter 11250’s gain extra speed due to lightweight. For the receiver I experimented with wiring into the BEC - burnt out the HS60 amplifier and a battery eliminator. My favorite is a 4cell, 250mah nicad receiver pack - reliable, always there, no collateral damage)

HARDWARE

"Keep it light."

"Run Octura's smallest rudder and 125" strut. Sharpen the leading edge of the strut. Rudder as far to starboard as possible."

(Due to a delay in obtaining Octura hardware I used a Hughey bracket and rudder and a Fuller strut. The Hughey hardware allows the control arm to be mounted on the left of the rudder. which enables the rudder to be mounted on the right edge of the tub.)

CABLE

"If you are going to run the motor in the front mount it so it is almost touching the bulkhead."

Preferred cable is a 16th piano wire in plastic tube.

"If you are going to run motor in the rear anything over 6 cells will require 0.125" cable. .098" cable only works in 6 cell and will not work with the motor in the front, as it is too long."

Center of Gravity

"This is not as important in a rigger as some other hulls". (Start with the CoG at 10 percent of the after plane i.e. the distance from the trailing edge of the sponson to the prop. Try to get the CoG at the trailing edge of the turn fin. Move it forward for rough water and rear ward for smooth water)

"If the tail drags try moving the CoG forward to help the prop surface".

PROP/STRUT

"Set the strut to zero degrees so the hull has a neutral angle of attack."

"The 1732 is preferred with the transom height 3/16th below flat in rear. Reduce the prop diameter by 1/32 and try delifting it until you have proper ride height."

(If it hops on the straights raise the strut so the prop is shallower - if it hops/trips in the corner drop the strut so the prop is deeper. If it helps to get the tail up angle the strut a little to increase lift)

Repairs

If you are unlucky enough to break a sponson boom it’s a simple matter to calculate the width of the sponson either by halving the length of the boat or by piecing together the old booms. A couple of detail points here:

1. rebuild the boat with 1/16th inch toe-in on the starboard sponson - it is not immediately evident on the original boat but it is there.

2. if you have to replace the booms in the sponsons - rebuild the sponson upside down with the booms against the under side of the sheeting which tops the sponson

3. when replaced the angle of attack on the sponson is seven degrees and the dihedral three degrees.