In the current rule book there is no mention of the boat having to qualify or race to be legal, therefore the Winston with the Circus cowling should be legal.
Here are the current rules from the IMPBA website.
Scale Unlimited Rules
General
The purpose is to realistically duplicate the Unlimited class of Hydroplanes.
Function of District Chairman
Responsibilities
a. Coordinates registrations for their district.
b. Has the power to appoint a committee to resolve protests.
c. Oversees the operation of scale hydros in the district and assists IMPBA in scale
hydro matters.
d. Keeps point record for district high-point trophy.
When vacancies occur, this position will be appointed by the current District Director and
the National Scale Hydro Chairman.
Registration Procedures
1. All boats must be registered with the District Chairman.
2. The District Chairman will require the following information in writing:
a. Name, address and phone number
b. IMPBA number
c. Unlimited name, year raced, and number
d. Length and beam of prototype boat and model
e. Prototype designer and boat colors
f. Must submit a photo of prototype boat
g. $5.00 annual District registration fee to be submitted upon completion of model & prior
to it competing in an
sanctioned event. Purpose of fees-monies is to cover registration printing c
costs & postage fees. A boat registered in one District may race in any District.
3. Boat must compete at a racing event within one year from registration.
Engine and Boat Specifications
1. All boats to be modeled after Unlimited hydroplanes from past or present.
2. All boats to be built to a scale of 1 1/2" to 1'0" (1/8 scale) plus or minus 10% of the beam
and 5% of the length.
3. Boats will look as scale as possible and meet the following requirements for racing and scale
judging:
a. Cockpit with driver
b. Complete all major lettering and paint schemes
c. Effort must be made to conceal glow engine with fake engine or cowling as per
prototype boats.
d. Minimum 50% of glow engine crankcase (flywheel is not considered part of crankcase)
must be concealed with fake engine or cowling as per prototype boat. April 2012 H - 5 Nitro Special Classes
4. Hull bottom and running hardware will not be judged or checked. However, hull must not deviate
from conventional 3-point hydro (unless prototype was a different design).
a. Hull bottom must be scale appearing.
b. Belly pants are acceptable to clear engine and/or flywheel.
c. Secondary front sponson running surfaces are optional.
d. Air traps are optional.
5. Engine must correspond with IMPBA Class "E".
6. Boat shall use same number of propellers as the prototype.
7. The drive dog must not extend beyond the transom unless the prototype's strut and/or drive dog
did so. Photo documentation may be requested for proof by race CD or district scale director.
8. No twin rudder assemblies allowed.
9. Boats should have the ability to change frequency.
Rules for Optional Scale Judging (Concourse)
1. Boat must accumulate 50 points in racing to qualify for scale judging.
2. Judging points to be separate from racing points.
3. All boats are to be judged no closer than 10 feet.
4. A picture must be submitted for the scale judging.
5. Points as follows:
a. 1 to 10 overall scale appearance
b. 1 to 10 for detail, engine, cowl, driver, etc.
c. 1 to 10 for paint job, markings, etc.
d. 1 to 10 for construction
Racing Rules
1. Normal IMPBA driving rules will be followed.
2. Only the registered owner can race his unlimited.
3. All boats shall run 3 qualification heats. There shall be no more than 6 boats in a heat.
4. At the conclusion of the qualification heats, the top 5 boats, based on point total, shall go into
the final.
5. To get the 6th boat for the final, the next 6 boats, based on qualification heat points, shall
compete in a consolation race with the winner going into the final. In the event that the boats
that have a tie are in 5th place, both boats go into the final and the final field of 6 boats is
established.
6. Heat races will be 6 laps in length and will follow standard IMPBA starting procedures. The
last boat running rule may be used, except at the International Regatta.
7. Frequency choice will be made in the point system. If a frequency conflict appears, the boat
with higher points will have preference. If the conflicting boat does not wish to change
frequency, it will be put into the consolation race and all other boats moved up.
8. Main Event and Consolation race points do not count toward the seasonal high point awards. April 2012 H - 6 Nitro Special Classes
9. Seasonal points accumulated in racing will go to registered owner at time of competition.
10. Cutting a buoy on the inside before or during the race shall incur a one-lap penalty. Hitting a
buoy on the outside at any time shall incur a 50-point penalty.
11. Normal heat racing rules can be used as optional racing format however each heat will be limited
to no more than 6 boats raced together at any one time. International Regatta racing will revert to
regular heat racing rules for Scale US-1 with the same 6 boat per heat limit.
12. If any removable parts (cowling(s), wing(s), dummy engine, driver, etc.) fall off
during a heat, except as the result of a collision, that boat will receive no more than
sixth place points for that heat. This penalization does not affect the finishing
placement of the boat, only the points awarded. The points awarded and placements of
the other boats in the heat are not affected by this ruling.
Records
1. Records shall be established in the Scale Unlimited class as listed in the “Records” section of
Rules of Competition.
2. Only boats properly registered will be eligible to establish records.
3. Only the registered owner can attempt to set a record with the registered scale unlimited
