• 1.0 References of Official Plans (Distributed by I.T.C.A.)
• 2.0 Arrangement
  • 2.1 Appearance
  • 2.2 Hull Shape
  • 2.3 Cabin Location and Size
  • 2.4 Cabin Interior Layout
  • 2.5 Cabin Side Windows
  • 2.6 Cockpit
  • 2.7 Cabin and Entry Hatches
  • 2.8 Deck Hatch, Anchor Well
  • 2.9 Equivalent Hardware
  • 2.10 Engine location
  • 2.11 Openings in Hull Exterior
  • 2.12 Hiking Assists

These specifications define the construction, equipment and measurement of the International Thunderbird Class sloop. Incorporated as part of these specifications are all of the Official Plans listed in the Reference Section below.

The issuance of an official measurement certificate and Gold Seal are dependent on the observance of these specifications, both in fact and spirit. Tolerances are specified to accommodate inaccuracies. However any boat measuring within these tolerances will meet the specifications regardless of the intentions or motives of the builder.

Specifications, however complete, cannot anticipate every possible situation which may arise. Anything that is not clearly covered in these specifications shall be brought to the I.T.C.A. Measurement Committee for a ruling.

These specifications shall be used in conjunction with the official set of plans. These specifications are requirements and the plans generally provide guidance, except where the specification requirement refers to the plans with such language as "as shown by" or "set forth in", in which case that part of the plans becomes a requirement. Where differences exist between the plans and the specifications, the text of these specifications shall prevail.

The builder shall supply a certificate to the Class Measurer stating that the yacht has been built to conform with the current International Class specifications and to the current official plans.

• 1.0 REFERENCES (Official Plans distributed by the I.T.C.A)

  • 1.1 Douglas Fir Plywood Association (American Plywood Association) Plan Number 85 (26' Racing -Cruising Sloop) Sheets 1,2,3, and 4. ***Note: Revised Thunderbird Wood Boat Plans will be issued in the near future to replace the Original Plans

  • 1.2 International Thunderbird Class Association Templates. ( an unnumbered drawing ). ***Note: These Template Plans will be updated in the near future and issued to Fleet Measurers.

  • 1.3 Cruising Cabin Detail, Thunderbird 26 foot Racing-Cruising Sloop. Additional Sheet 3A to Plan No.85 Sheet 1 to 4. Issued by the International Thunderbird Class Association, December. 1979 (1 Sheet).

  • 1.4 Thunderbird Cruising Cabin Construction Procedure and Material Identification (No document number, 6 Sheets).

  • 1.5 Instructions for the Construction of a One-Off Fiberglass Thunderbird Sailboat. I.T.C.A. Publication 20, Issued June, 1982 (28 Sheets).

  • 1.6 One-Off Fiberglass Thunderbird Plan, I.T.C.A Publication 21. (4 Sheets).

• 2.0 ARRANGEMENT
  • 2.1 The external appearance of the yacht shall conform with that set forth in the official plans.

  • 2.2 Hull shape shall conform with that set forth by the official plans (Reference 1), within the tolerances noted below in these specifications.

    NOTE: Table of offsets on several issues of the original plans will result in a hull length of 26-2" (7.930m). See Section 4.1.1 for proper hull length requirements. Following the construction instructions. the plans will yield a hull with the proper length.

  • 2.3 Cabin location and size shall conform to that shown on Douglas Fir Plywood Association (American Plywood Association) Plan No.85 as amended by the I.T.C.A or on the One-Off Fiberglass Thunderbird Plan, I.T.C.A Publication 21, or alternate versions approved by the Board of Governors.

    The Board of Governors shall consider for approval as alternate versions only those that comply with the following criteria:

    • 2.3.1 The cabin height, width, length, camber, location, and angles (slopes) shall be within the extremes defined on Plan 85 and Publication 21 except for the angle of the front of the cabin, which shall not be less than 33 degrees when measured against the sheer.

    • 2.3.2 The cabin profile should be essentially flat.

    • 2.3.3 The cabin shall be in keeping with the Thunderbird Class racing and cruising function and appearance.

      For an alternate version to be considered for and receive approval. drawings shall be submitted to the Board of Governors prior to the start of construction. These drawings shall be accurately scaled and dimensioned plan and profile views, showing the entire deck. cabin with window layouts. the cockpit and the coamings. Section views at Bulkheads 2,3, and 4 and a bill of material shall be included on the drawings. Upon approval, the drawings shall be official plans and shall be the property of the I.T.C.A
      

  
  
  ENVELOPE AVAILABLE FOR ALTERNATE CABIN CONFIGURATIONS
  • 2.4 Cabin interior layout is optional. The intent of this rule is to permit various cruising layouts and not permit a stripped shell when racing. Bunks and counter space, accommodation for equipment specified in Section 10, plus adequate storage constitute a complete yacht.

  • 2.5 Cabin side windows may contain an extra vertical post (making two windows per cabin side). Front cabin windows may be omitted.

  • 2.6 Cockpit arrangement is optional, except for the following restrictions.

    • 2.6.1 Coamings may slope outward up to 15 degrees from vertical. Their design should approximate the shape shown on the referenced wood or fiberglass construction drawings. Height measurements will be from the sheer (sheer is the external deck edge at side) to the top of the coaming specified at two (2) locations: Bulkhead #6 and at the back of the cabin. The minimum heights are 4-l/2" (114.3 mm) above the sheer at Bulkhead #6 and 7-1/2" (190.5 mm) above the sheer at the cabin. The top of the coaming may not deviate more than 3/4" (1 9.1 mm) from a straight line drawn between Bulkhead #6 and the cabin.

    • 2.6.2 Provision for self-draining must be equivalent to that shown on the plans.

    • 2.6.3 Volume may not be greater than shown on the plans.

  • 2.7 Cabin and Entry Hatches. Dimensions shall not exceed those of the plans. Various methods of lifting and/or sliding cabin hatch covers are permitted. Cabin hatch construction shall use materials in accordance with Section 3.1 Hatch strength shall be equivalent to the hatches shown on Reference I. The entry hatch must be capable of being readily closed to the height of the cockpit seats to insure the self-draining capability of the cockpit. Drop slides or double doors meet this requirement.

  • 2.8 Deck Hatch, Anchor Well

    • 2.8.1 The foredeck area shall have no holes or depressions, except for vents (4" (101.6mm) max.), anchor well, and hatch which are all optional. If they are installed they must be sized and located according to plan(s). They shall have a cover or door of material in accordance with Section 3.1, with strength equivalent to the hatch shown on Reference 1. The anchor well shall have a drain to the outside of the hull. The anchor well shall be utilized for the storage and use of the yacht's anchor and ground tackle. Any use associated with sail handling is not permitted.
  
  
  Anchor Well Arrangement
  

  • 2.8.2 The Anchor Well Arrangement shown above is to control size and location. Detail design is at the discretion of the builder.

  • 2.8.3 Location, dimensions and construction of the aft storage and motor well hatches are optional. Hatch strength shall be equivalent to the hatches shown on Reference 1. The construction material must be in accordance with Section 3.1. This is to permit various motor well designs, particularly that which allows a tilting motor arrangement. This does not permit the relocation of Bulkhead #6.
  • 2.9 Equivalent suitable hardware may be substituted for that specified on the official plans.

  • 2.10 Engine must be located entirely aft or Bulkhead #5 and the propulsion unit must be fully retractable.

  • 2.11 Openings in the exterior of the hull for the toilet, sink, cockpit self-drainers. and outboard well may not be taped or sealed off at anytime so as to render them inoperative.

  • 2.12 Hiking assists are permitted provided that they are attached to the cabin, coaming or cockpit structure. and that they do not extend beyond an imaginary line projecting from the gunwale which is parallel to the vertical center line of the boat.