Inboard Multi-Hull

2.1 Introduction

2.1.1 Performance Parameters / Intent of the Rules – These parameters are merely a guideline for RWO officials in the creation and/or amendment of technical rules to maintain competitive balance and contain costs. Accordingly, RWO reserves the right to take whatever actions necessary, at any time, to ensure that boats competing in the class perform within these parameters in competition.

2.1.2 Interpretation of Rules – If there is a disagreement or dispute regarding the meaning or application of the SUPERCAT Technical Rules, the interpretation and application of the RWO rules compliance process shall prevail.

2.2 Changes to Existing or Introduction of New Equipment

2.2.1 Warning to racers – If this rulebook does not specifically say that you can do or use something then you must consider that the action, change or component is illegal. No equipment or race boat in violation of these rules will be considered as having been approved by reason of having passed through pre-race inspection or post-race inspection at a prior event, “unobserved”.

2.2.2 Written Approval Required – Any questions about the legality of any change, or any action, part, or component must be submitted in writing and answered in writing by the RWO prior to the change or use. RWO is empowered to make any technical rule changes it deems necessary to maintain competitive balance and/or safety for the boats competing in the SUPERCAT Class.

2.3 Exclusivity Prohibited

All boats as well as every part used in connection therewith, including but not limited to engines, outdrives, transmissions, crash boxes, and propellers (and all parts and components related thereto) must be both manufactured and intended for sale to the public at commercially reasonable prices. Exclusivity agreements of any type that have not been approved by RWO are strictly prohibited. This rule applies to competitors only and shall not be construed in any manner whatsoever to limit or restrict RWO from entering into exclusivity agreements such as official sponsorships involving single source vendors, suppliers, manufacturers or producers.

2.4 Enforcement of Rules

The purpose of these rules is to ensure competitive balance between SUPERCAT racing teams. RWO thus reserves the right to take whatever actions it deems necessary to enforce these rules, including but not limited to impounding any boat and/or parts and components thereof for inspection purposes, and/or prohibiting the use of any part or component which it deems gives a team an unfair competitive advantage, in its sole and absolute discretion. All illegal parts or components become the property of RWO. RWO Race Officials are authorized to decide if an equipment change is an attempt to violate the rules. They can and will disqualify an entry in violation of the spirit and intent of these rules or take such other action as they deem necessary to maintain competitive balance in the class.

2 .5 Rule Changes to Maintain Competitive Balance

RWO recognizes that there are considerable differences in boat length, sponson design, tunnel width, angle, shape and other aspects of boat design. Accordingly RWO reserves the right to make adjustments at any time to boats, engines, drives, propellers, etc. individually or categorically, to maintain competitive balance based upon experience in race conditions.

2.6 Boat Specifications

2.6.1 Dimensions

Length:36’ minimum to 46’ maximum
Hull Type:Catamaran
Beam:12’ maximum
Tunnel Width:66” maximum measured at keel
Height:Class must measure at least 48” from the keel to the deck forward of the canopy (not including the canopy).
Weight Minimum:9500lbs

2.7 Minimum Weight Measurement

is determined at the end of the race. All boats required or directed to weigh by the Chief Referee or Inspector must report to the Crane of the Day, the same crane must be used for both entering and exiting the water. It will be the responsibility of the Owner, Driver, or designated Crew Member to present the boat for Post-Race Weighing with the boat in the lifting harness in a level position, with the hull drain plugs removed and the boat empty of water, with all ballast tanks empty, and all helmets and jackets removed. If the Inspector or Chief Referee finds otherwise, the boat will be immediately assessed a two (2) minute penalty. No private cranes or scales will be utilized for Official Weighing compliance purposes. The weight will be an all-up weight including, engines, residual fuel, drives, propellers, fixed ballast (i.e. that which is used from start through completion of race). No multiple weighing. One only. One in and one out.

2.8 Canopies

SUPERCAT registered race boats are required to have canopies.

2​.8.1 All canopied boats are recommended to comply with the latest canopy design and technology. Contact the boat manufacturer for their canopy standards.

Any damage to canopies must have a notarized certified letter from a manufacturer of canopies authorizing the continued use in a race.

2.8.2 Non-compliance RWO has the authority to deny entry to any race boat subject to these rules that has non-compliant cockpit safety systems.

2.9 Engine Specifications

The SUPERCAT 510 CID Engine will be the only engine approved for the SUPERCAT Class.

2.9.1 Displacement: Maximum 510 CID, minimum 496 CID per engine, (Max. 1020 CID total) with a maximum 4” stroke crankshaft.)

2.9.2 Compression Ratio: The maximum compression ratio allowed is 9.5.1 measured by whistler device calibrated at race site with master cylinder.

2.9.3 Valve System: Two valves per cylinder operated via pushrods. Maximum gross cam lift – measured at the valve is .720 inch with zero lash. Variable cam timing is not allowed.

2.9.4 Block: Cast iron – must be approved by RWO Chevrolet – design blocks with 9.8” or 10.2” deck heights are approved. Chevrolet – design blocks manufactured by General Motors, World Products (Merlin), and Dart Big M are approved.

The​ ​use​ ​of​ ​any​ ​other​ ​block​ ​requires​ ​the​ ​approval​ ​of​ ​RWO. Sleeves – or bushings may be used providing the original OEM (GM) lifter bore location is not changed. Pushrods – must ride in the center of the lifter (no offset lifters).

2.9.5 Internal Components: Materials – Crankshaft, connecting rods, pushrods and wrist pins must be made of steel. Titanium or other materials not allowed. Single plane crankshafts – are not allowed. Crankshaft throws must be timed in accordance with OEM specifications. Crankshaft limited to a maximum 4” stroke.

2.9.6 Heads: Approved cylinder head – is big block Chevrolet Brodix – BB2 PLUS 26 degree Head. They are the only approved aluminum cylinder heads allowed with the Stock OEM cast specifications. No modifications to the Stock OEM castings are allowed.

2.9.7 Valve Work: Spec cylinder head serial numbers – must remain on the head and may not be defaced or altered.

2.9.8 Modifications/Repairs Using offset head guides or altering the stock mounting location of the head on the cylinder block is not allowed. No welding modifications are allowed to the original head castings. Heads must be returned to Brodix for repair. All repairs will be certified in writing to the RWO.

2.10 Intake Manifold

2.10.1 Carburetor Spacers – or adapters are allowed, maximum of 2.5” between the bottom of the carburetor and the top of the manifold is allowed.

2.10.2 Any stock cast intake manifold. The manifold may be port matched up to 1 1⁄2 inches to match cylinder heads. No fabricated or tunnel ram type manifolds may be used.

2.11 Induction System

2.11.1 Approved Fuel – 91-93 Octane no fuel additives.

2.11.2 Only one carburetor is allowed per engine.

2.11.3 Approved Carburetors – Any Holley Dominator style carburetor is allowed.

2.11.4 Carburetors may be purchased from any source.

2.11.5 Fuel injection – is not allowed.

2.12 Exhaust System

2.12.1 Runner Length/Materials – Exhaust manifolds may be cast or fabricated with no more than 15-1/2” (inches) of individual primary runner length measured at the centerline of any runner from the cylinder head port to the common collector. The overall length includes any gaskets, adapters, or wedges from the exhaust ports to the common exhaust collector. No modifications to the exhaust that increases runner length or gives the effect of longer individual runners are allowed. This includes but is not limited to merge collectors, divider plates or turbulence cones. The stock Mercury style 525 CMI header, with 1 7/8” ID is permitted.

2.12.2 Any non-divided (common collector), round, square, rectangular or oval, elbow, riser or tail pipe is allowed. The engine exhaust manifolds and pipes from engine outlet to point of exit from hull or deck must be water-cooled by water jackets. The exit from the hull or deck must be located in such a position whereby exhaust fumes cannot affect the crew.

2.13 Transmissions

2.13.1 General: All boats competing in the SUPERCAT Class must have propulsion systems capable of turning the propellers in either direction or maintaining a neutral (standstill) state while the engine is running.

2.13.2 Single speed – transmissions / crash boxes capable of forward, neutral and reverse are allowed.

2.13.3 Multi speed – transmissions are not allowed.

2.14 Lubrication (Engine)

2.14.1 Wet Sump – and internal oil pumps are allowed.

2.14.2 Dry Sump – External oil pumps or dry sump systems are allowed, however, a maximum of three scavenging pump sections allowed on dry sump systems.

2.14.3 Intake Valley – must remain as cast with NO alterations to prevent oil flow from the valley to the crankcase. No raised sections may be attached or formed with any material around oil drain openings in the intake valley. No “damming” or collecting of oil by any means is allowed in the intake valley.

2.15 Ignition

2.15.1 Distributor – must remain in factory delivered location.

2.15.2 Electronic Ignitions – Engines are required to use the MSD Digital or Analog ignition system LIMITED TO 7000 RPM’s, A G2X DATA LOGGER MUST BE INSTALLED and maintained to monitor the RPM level during the race. The RPM LEVEL during the entire race must be verifiable on the Data Logger by the RWO Inspector upon the completion of the race, during the Post-Race Inspection. Ignitions with an internal dial up RPM Limiter will be set at 7000 RPM’s and sealed by the RWO Inspector. The wiring harness of the system must be accessible and provide the ability for an RWO Inspector to examine it.

Any boat competing in the SUPERCAT Class that exceeds the above listed MAXIMUM RPM LIMIT, as determined by the RWO Inspector “WILL BE” awarded last place points and will not be eligible for trophies, flags or prize money.

2.15.3 Crank triggered and belt drive ignitions – are not allowed.

2.15.4 Coils – Ignition systems are limited to one (1) ignition coil. Individual ignition coils per cylinder are not allowed.

2.15.5 Back up ignition systems – are allowed.

2.15.6 Spark – must be distributed via distributor rotor and cap.

2.16 Engine Supplier

2.16.1 RWO will allow any engine builder to supply engines that meet the SUPERCAT engine specification.

2.17 Outdrive Specifications

2.17.1 Approved Drive Systems – SSM VI Drive Type. Drive must retain their OEM configuration and specification. No internal or external modifications are allowed.

2.17.2 Gear Reduction – #6 Drive with 1:61 gear ratio, at the prop only. Surface Drives not allowed.

2.18 Propeller Specifications

2.18.1 Propellers must be approved by RWO.

2.18.2 Maximum 5 blade propellers, Cast Stainless Steel, no forged units of any type. No titanium. Manufacturers, Mercury, Hering and Rolla are approved.

2.18.3 Other manufactures of cast propellers may apply to RWO for approval.

2.18.4 Modifications – Propellers may be modified from the original factory casting. Polishing, grinding, bead blasting, media blasting, welding and machining are allowed.

2.18.5 Availability – Propellers must be intended for sale to the public at commercially reasonable prices and available to all racers.

2.18.6 Thickness – All propellers will be measured and limited to a minimum thickness. The standard blade thickness will be the normal RWO Lab Finish. (See Chart)

2.19 Propeller Inspection Specifications for SUPERCAT Class


Propeller​ ​DiameterStrike​ ​Radius​ ​at:
15inch2”4 ¼"6 ½"
15 ¼inch2”4 5/16"6 5/8"
15 ½inch2”4 3/8"6 3/4"
15 ¾inch2”4 7/16"6 7/8"
16inch2”4 ½"7"
16 ¼inch2”4 9/16"7 1/8"
16 ½inch2”4 5/8"7 ¼"
16 ¾inch2”4 11/16"7 3/8"
17inch2”4 ¾"7 ½"
17 ¼inch2”4 13/16"7 5/8"
17 ½inch2”4 7/8"7 ¾"
17 ¾inch2”4 15/16"7 7/8"
RadiusDistance​ ​from​ ​Leading​ ​EdgeDistance​ ​from​ ​Leading​ ​Edge
2”1​ ​3/8”.283”
4​ ​¼”​ ​to​ ​5”1​ ​​½”.182”
6​ ​½”​ ​to​ ​8”1​ ​11/16”.115”
RadiusDistance​ ​from​ ​Leading​ ​EdgeThickness
2”1​ ​½”.475”
4​ ¼”​ ​to​ ​5”1​ ½”.302”
6​ ​½”​ ​to​ ​8”1”.130”

2.20 Air Scoops

​It is illegal to completely seal the inlet air track running from external openings to the flame arrestor. Fresh air ducting must be no closer than 2” at its nearest pointes to the engine and/or flame arrestor. Sealing or pressurizing the engine compartment is not allowed. The RWO reserves the right during, or in post-race inspection, to install (place) an atmospheric pressure measuring device to certify that a positive pressure engine compartment has not been created. For purposes of enforcement any reading during a race or in post-race testing exceeding +1.1 atmospheres ​of pressure, will constitute a violation of this rule with disqualification being the remedy.

2.21 Ballast

​No ballast tanks or devices to support ballast tanks are allowed. Any Race Boat which presently has ballast tanks built into the integral support of the boat must remove all supporting plumbing and electrical devices and provide a permanently open inspection port through which the interior of the tank can be thoroughly inspected. No transferable closed liquid systems are allowed.

2.22 Engine Hatches

​with or without scoops are allowed.

2.23 Illegal Parts

​Use of illegal or unauthorized parts on a SUPERCAT Class race boat will result in the confiscation of the said parts. Failure to surrender the illegal part(s) will lead to a mandatory suspension for the boat, the boat owner and all riding crew members until the illegal part(s) are surrendered to RWO. It shall be the responsibility of the owner or his designated representative to take whatever actions are necessary to ensure the correct components are present.