T I P Catamaran Rating
Simple description ; Combination rating system using the best features of Texel ISAF and Portsmouth.
= T I P Catamaran Rating;proposed outline for consideration and developmental concepts and ideas .
Base rating equation per Texel & ISAF - Rated Length Rated Sail Area- Rated Weight, as listed per Tex. Rating.
Proposed from this proven base rating along with several modifications for use in N A is a 2 wind speed category based on wind-speed effects below 8 . Also an on trap windspeed above 8, --the 3 range B. scale ,-based on beam and board effects at higher speeds, -and rated sail area inc. adapted spin rating system per current ISAF.
The ISAF spin added rating equation is proposed for use producing similar rating numbers with Tex.through a more thorough means of measurement and rating actual spin area -rather than the added 4 pt Tex. rating currently uses for all spin rigged cats by specifying a targeted size for each length and adding extra penalty for those over.
The ISAF added spin rating calc. allows any spin size to be readily rated per area- per sail-maker, -along with any modification.
A spin efficiency factor is also proposed to accurately rate spin area per design in class.
A [Handicap Added Factor } based on Portsmouth Rating difference from modern catamaran design base model target rating or comparable non spin Formula design per rating conversion in each length category . This theoretically factors in Portsmouth rating handicap to the updated base rating and provides more favorable rating numbers applied to older design classes as compared to modern cat design.
Assumptions in T I P rating;as proposed--
1-Tex. rating base is developmental and will reflect lower speed range accurately as foundation for all extended and added modification factors ,- .-inc. upper wind rating added and cat design of 22 ft and greater as modified.
2-ISAF Spin calc method with added Eff factor per aspect ratio will average in the 4 pt added range per each typical class design sail area.
3-Wind-speed factors of total beam ,-board correction ,-rated sail area effects to rated L and rated W inc.crew weight correct to an accepted average in the upper range category.
4- Future wind-speed category will be required to address new developments in catamaran design of angled lifting boards and foils . Also planning hull effects along with hull P C rating effect in 2 wind-speeds proposed. Along with other future sailplan and design developments as required.
5-Method for adding Portsmouth rating per comparable rating of non spin design target in each Length category is accurate as applied to older cat classes having lesser non factored design features per criteria and class age original form as outlined.
TIP Catamaran rating numbers in wind-speed category may be cross -checked with current rating system numbers for comparison ,-all proposed rating calc methods are developmental.
Advantages
Utilizes the best features of the 3 main current rating systems in use ----Tex. Isaf and P. =TIP
Provides an accurate proven rating number for modern cat designs, --no provisional number is needed-
Eliminates the page of modification factors that utilize a one penalty factor fits all approach regardless of the size spin ;jib ;main mast height, -etc.
Provides a much larger base pool internationally of base rating information to help verify rating accuracy.
Integral rating system, more compatible to promote large class racing groups in N A .
If any catsailor would like to help develop any aspect of this rating system as outlined in these added categories --
1- Spin rating calc method per ISAF rating and spin eff rating factor added per aspect ratio.
2- Windspeed modification factors ,-board effects ,-rated sail area to weight and length,-and beam effect calc applied to wind-speed. Consideration for future windspeed category for angled lifting boards and foil effeciency ,and hull form inc. planning types per current new design .
3- H A F ;Integrating updated Portsmouth rating as applied to handicaping older design per criteria added to the equation and calc method applied .
Please contact or post your concepts and ideas for rating catamarans in N A .
A series of related concepts and calc proposals for each can be found on this forum under . Texel adaptations for use in N A .
very boring subject ,-but is a giant puzzle with multiplex coumpounded problems to resolve fairly with ideals of accurate rating of catamaran design while maintaining freedom of design development , and ideals of fair sailing as outlined per ISAF rules as ultimate goal.
Carl
