IJSBA is pleased to announce the final changes to the 2018 IJSBA Competition Program.  The IJSBA Board of Directors passed the below listed changes by unanimous consensus today, February 23, 218

These rule changes will be transcribed to rule book within seven days and will be published for peer review before becoming finalized.  

Please send any questions or requests for clarification to info@ijsba.com.  


  Sport Spec watercraft shall be afforded a second set of sponsons.


  1. Runabout Stock:  Aftermarket Valve Retainers to be allowed
  2. Runabout Limited: No Changes
  3. Runabout Open: To Be Replaced With Superstock and Runabout Open to be merged with Runabout Modified/GP
  4. Runabout Modified/GP:  No Changes


Runabout GP/Modified will continue to exist and shall be a class offered on Saturday at the 2018 IJSBA World Finals.  Sunday will offer Runabout Superstock which shall consist of a Limited Class Runabout with the following additional provisions:  aftermarket hood, aftermarket forced induction system.



  1. Ski Lites:  No Changes
  2. Ski Stock: No Changes
  3. Ski Limited:  No Changes.  Ski Limited will be kept as a class description in addendum.  However, in most cases, especially at World Finals, Ski Limited will be replaced with the newly created Mod Lites
  4. Ski GP:  Ski GP is a class that allows two stroke engines, up to 1300cc, naturally aspirated four stroke engines up to 1100cc, and forced induction four stroke engines up to 900cc.  All configurations allow full modified rules.  IJSBA reserves the right to require blow off valves and tuning restrictions to be implemented*.
  5. Ski Modified:  Ski Modified is a Pro Level and Expert Level class for 2018.  Ski Modified allows all eligible Ski GP watercraft as well as all eligible Ski Superstock watercraft.  Forced induction four stroke units may have displacements up to 1100cc. IJSBA reserves the right to require blow off valves and tuning restrictions to be implemented*.  
  6. Ski Superstock:  Ski Superstock is intended to be a class that services, primarily, the existing 2018-2019 Kawasaki SX-R.  Ski Superstock allows all provisions of Ski Stock plus the following additional provisions:  aftermarket pistons, aftermarket exhaust, aftermarket intake systems, head porting, aftermarket camshafts, aftermarket valve systems, aftermarket hood, aftermarket ECU, aftermarket propulsion pump, aftermarket water routing.


*Effective immediately (February 23, 2018): IJSBA requires the installation of an approved mechanical blow off valve which shall release all boost pressure above 8 PSI for all Ski watercraft with a displacement of 900cc and below and 6 PSI for all Ski watercraft above 900cc.  A tolerance of .25 PSI shall be allowed without penalty.  On July 2, 2018, competitors may submit appeals to IJSBA stating that the boost pressure limits need to be revised for the 2018 World Finals.  On July 8, 2018, IJSBA will no longer accept such appeals.  IJSBA will announce, on, or by, August 8 the response to any such appeals and the applicability of these responses to the 2018 World Finals.



Ski Mod Lites will begin in 2018 as a pilot program intending to create a class that services the aftermarket industry and the competitors who wish to engage in aftermarket based performance while maintaining the costs and speeds traditionally associated with mid-level Ski performance.  Competitors may use aftermarket hulls in most circumstances.  Competitors may use two stroke or four stroke homologated engines.  This class is a developing class which is expected to evolve over the next coming years.  Mod Lites will, generally, replace Ski Limited.  Junior 13-15 Limited will change to Junior 13-15 Mod Lites immediately upon the ratification of Mod Lites rules.

1. At the outset of Mod Lites, all immediately eligible engine packages may be affixed to an aftermarket hull that was eligible for the 2017 Modified class.  By the end of 2018, hull manufacturers and hull owners must participate in the IJSBA Aftermarket Hull manufacturing and monitoring system.  This will require affixing IJSBA approved hull identification numbers and maintaining a chain of custody and history of the aftermarket hull.

2.  Competitors who choose to utilize a two stroke engine in Mod Lites may select from any OEM homologated engine that was offered by the original manufacturer of a homologated Ski Watercraft (Yamaha Superjet/Kawasaki 750/SXR).  These configurations will be entitled to all engine, hull, electronic, and propulsion privileges originally afforded to the Ski Limited classes.  IJSBA will begin testing a configuration of allowing a triple cylinder two stroke engine to be affixed to an OEM hull by means of a bed plate with Lites Rules applied to the additional modifications.  However, this is not an approved package at this time.

3.  Competitors who choose to utilize a four stroke engine in Mod Lites may select either a Sea-Doo 900 ACE engine or Yamaha TR1 1050 engine.  If a competitor chooses a Sea-Doo 900 ACE, the engine is restricted to Rec-Lites rules plus the allowance of an aftermarket camshaft and aftermarket valve system.  If a competitor chooses a Yamaha TR1 1050 engine, the competitor must adhere strictly to Rec-Lites provisions.  In either case, the competitor must use all OEM ECU and electronic systems from the original OEM engine package selected.  Aftermarket pump systems shall be allowed.  Competitors may use Hydrospace S4 watercraft to previous Stock Class specifications.


 Please send any questions or comments, immediately, to info@ijsba.com.  


Expected Class List For 2018 World Finals:

Pro Classes

Pro Ski Modified (Sunday Class)

Pro Runabout Superstock (Saturday Class)

Pro Freestyle  

Pro Am Classes

GP Ski  (Saturday Class)

GP Runabout (Sunday Class)

Runabout Stock

Runabout Naturally Aspirated Stock

Runabout 1100 Superstock  (800cc Maximum for Two Stroke, 1100cc Maximum for Four Stroke)

Ski Stock (2017 Kawasaki SX-R is permitted without a restrictor plate)

Womens’ Ski 

Ski Lites

Ski Mod Lites

Runabout Limited

Endurance Runabout Open

Expert Classes

Expert Ski Modified 

Expert Ski Stock 

Expert Runabout Superstock

Expert Veteran’s Runabout

Amateur Classes

Amateur Freestyle 

Amateur Ski GP 

Amateur Ski Lites 

Amateur Ski Mod Lites 

Amateur Veteran’s Ski Stock (Two Stroke Limited Legal Ski allowed- this year only).

Amateur Veterans Ski GP  

Amateur Runabout 1100 Superstock (See Open Class Rules, 800 CC Limit For Two Stroke)

Amateur Runabout 1100 Limited (Up To 1100cc Normally Aspirated Four Stroke, 800 CC limit for Two Stroke)

Amateur Runabout 1100 Stock (Four Stroke Powered Runabout Only: Sea-Doo Spark; Yamaha EX)

Amateur Runabout Rec Lites

Amateur Women’s Ski Lites  (All participants who hold an Expert License, All participants who have had a World Finals podium finish in Novice Women’s Ski, and participants who have participated in Pro Am Women’s Ski must petition IJSBA for eligibility in this class).

Amateur Runabout Limited

Novice Classes

Novice Ski Stock 

Novice Ski Limited

Novice Runabout Stock

Novice Runabout Naturally Aspirated Stock

Junior Classes

Junior Ski 10-12 Stock (2017 Kawasaki SX-R Allowed only with IJSBA approved restrictor plate)

Junior Ski 10-12 Lites (Stock Rules 2 Stroke Only)

Junior Ski 13-15 Stock (2017 Kawasaki SX-R Allowed only with IJSBA approved restrictor plate)

Junior Ski 13-15 Lites (Stock Rules 2 Stroke Only)

Junior Ski 13-15 Mod Lites


Other Classes Open To All Skill LevelSport GP

Sport Spec (All Skill Level, Pro Ranked Competitors Must Petition To Participate)

Classic Ski Two Stroke Limited  (Limited Class Rules, Two Stroke Only)

Master’s Ski GP  (2017 Kawasaki SX-R is not allowed in this class.  No displacement above 1300cc.  Forced induction Ski are limited to 950cc)

Master’s Ski Stock (2017 Kawasaki SX-R allowed to Stock Class specifications Only, Two Stroke Ski allowed to Limited Class specifications- this year only)

Vintage Ski (Two Moto’s- Combined Score for Overall)

Vintage X2 (Two Moto’s- Combined Score for Overall)

Women’s Runabout (Limited Class Rules For Two Stoke, Stock Rules For Four Stroke Plus Aftermarket Seat Allowance)

Ski Endurance  Sprint (2017 Kawasaki SX-R Allowed to Stock Class Specifications)


Ski Modified

Runabout Open

Sport GP

Four Stroke Ski Stock