Club Certificate2026
THUNDERHEADUSA 75
US SAILING
1 ROGER WILLIAMS UNI WAY
BRISTOL, RI 02809
USA
Rated boat velocities in knots
Wind Velocity 4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Beat Angles46.2°43.3°40.4°39.3°38.6°38.4°37.9°37.4°37.5°
Beat VMG2.313.344.094.635.025.265.395.535.54
52°3.635.076.016.707.177.467.607.717.74
60°3.885.316.246.927.377.657.797.897.95
75°4.045.466.397.087.547.828.008.188.26
90°3.885.326.397.207.697.978.188.428.61
110°3.895.576.727.527.988.278.508.829.19
120°3.765.416.587.417.928.258.539.089.42
135°3.274.756.006.977.628.048.358.969.54
150°2.714.025.126.136.937.507.898.428.94
Run VMG2.353.484.435.316.006.516.937.598.12
Gybe Angles140.3°144.2°147.4°146.7°149.4°151.6°156.4°163.7°175.3°
APH ToD:558.0CDL: 10.097APH ToT: 1.0753CertNo:US19971
BOAT
ClassCustomDesignerPhilip RhodesBuilderabeking & RasmussenAge date01/1961Series date01/1961Offset fileUS19971.offData fileUS19971
HULL
Length Overall14.399 mMaximum Beam3.980 mDraft3.061 mDisplacement17,831 kgDLR12.3209IMS DivisionCruiser/RacerDynamic Allowance0.620%Age Allowance0.650%RS Assessment-0.229%
PROPELLER
InstallationIn ApertureTypeFeathering 3 bladesDiameter0.518m
CREW
Maximum weight820 kg(default)Minimum weight690 kg ✱ when appliedCrew Arm Extension
SAIL AREAS (m²)
MeasuredRatedMainsail48.7849.54Headsail Luffed76.9776.97Headsail Flying88.1988.19SymmetricAsymmetric161.52161.52 (All asymmetric spinnakers with SHW/SFL > 85%)
STORM SAIL AREAS Maximum (m²)
Trysail15.81Storm Jib14.78Heavy Weather Jib39.91
SAIL LIMITS
Headsails6Spinnakers5
STABILITY
Righting Moment 318.0 kg·m Stability Index 130.0
The owner and any other person in charge is responsible that boat is complying with her certificate in accordance with RRS 78.1 and ORC Rule 304.
ORC Ref  04560004VKT Issued on 23/07/2026 Valid until 28/02/2027
VPP ver: 2026 1.00 | © ORC | www.orc.org
Club Certificate2026
THUNDERHEADUSA 75
US SAILING
1 ROGER WILLIAMS UNI WAY
BRISTOL, RI 02809
USA
Time Allowances in secs/NM
Wind Velocity 4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Beat VMG1557.21078.5879.9777.5716.9684.7667.6650.8649.6
52°991.5710.1598.6537.1501.8482.8474.0466.6464.9
60°927.0677.6576.9520.2488.3470.9462.1456.5452.8
75°891.5659.9563.6508.6477.7460.4450.1440.1435.7
90°928.8676.2563.3499.9468.0451.5440.3427.8418.2
110°924.3645.9535.6479.0451.4435.4423.5408.1391.6
120°957.3665.0547.0485.8454.5436.3421.8396.3382.2
135°1100.8757.8599.7516.7472.2447.9431.2401.7377.5
150°1326.7895.7703.4587.0519.4479.9456.3427.7402.7
Run VMG1531.91034.3812.2677.9599.7553.2519.6474.4443.5
Selected Courses
Windward / Leeward1544.51056.4846.0727.7658.3619.0593.6562.6546.6
All purpose1169.3814.9664.1580.9534.2508.1491.6471.7459.7
Single Number Scoring Options
Course Time On
Distance 		Time On
Time
Windward / Leeward691.70.8674
All purpose558.01.0753
Custom scoring options for Australia
Scoring Option Time On
Distance 		Time On
Time
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Custom scoring options for Austria
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Brazil
Scoring Option Time On
Time
Upwind "bolina"0.7698
Downwind "popa"0.8991
70% up, 30% down "Ilhabela"0.8045
30% up, 70% down "Ilhabela-inverso"0.8560
Custom scoring options for Bulgaria
Scoring Option Time On
Distance 		Time On
Time
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Predominantly Upwind604.00.9935
Predominantly Downwind571.61.0498
Custom scoring options for Canada
Scoring OptionTODTOT Scoring OptionTODTOT Scoring OptionTODTOT Single Number AP582.81.0295 Predom. Rc High450.11.3331 5B SF Bay L/M767.60.7816 TriNum AP Low739.50.8113 Predom. Dn Low907.70.6610 5B SF Bay Med647.30.9269 TriNum AP Med554.11.0828 Predom. Dn L/M653.80.9177 5B SF Bay M/H579.61.0352 TriNum AP High488.31.2288 Predom. Dn Med547.31.0963 5B SF Bay High550.81.0892 TriNum W/L Low998.70.6008 Predom. Dn M/H487.41.2311 5B AP Low828.00.7247 TriNum W/L Med687.20.8731 Predom. Dn High457.51.3116 5B AP L/M637.80.9407 TriNum W/L Hig588.31.0199 ChiMac Up Low785.70.7637 5B AP Med544.91.1012 Predom. Upwind631.50.9502 ChiMac Up Med699.20.8581 5B AP M/H494.61.2131 Predom. Reaching560.41.0706 ChiMac Up High599.71.0005 5B AP High473.01.2684 Predom. Downwind600.40.9994 ChiMac Off Low770.80.7784 5B W/L Low1125.80.5329 Predom. Up Low906.80.6617 ChiMac Off Med673.70.8906 5B W/L L/M807.60.7430 Predom. Up L/M674.60.8894 ChiMac Off High561.41.0687 5B W/L Med673.50.8908 Predom. Up Med581.21.0323 ChiMac AP Low775.00.7742 5B W/L M/H598.11.0032 Predom. Up M/H532.91.1260 ChiMac AP Med684.20.8770 5B W/L High565.21.0616 Predom. Up High514.81.1655 ChiMac AP High579.11.0361 W/L 60-40 Low1130.40.5308 Predom. Rc Low811.00.7399 BayMac Cove Island894.80.6705 W/L 60-40 L/M815.90.7354 Predom. Rc L/M600.90.9984 BayMac Shore887.90.6757 W/L 60-40 Med685.10.8758 Predom. Rc Med515.71.1634 Harvest Moon489.91.2248 W/L 60-40 M/H612.80.9791 Predom. Rc M/H470.71.2748 5B SF Bay Low942.20.6368 W/L 60-40 High582.81.0294      SA/DSPL Up18.25SA/DSPL Dn30.52
Custom scoring options for Cyprus
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Denmark
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Spain
Scoring Option Time On
Distance
Coastal/Long Distance608.9
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Estonia
Scoring Option Time On
Distance 		Time On
Time
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Custom scoring options for Finland
Scoring Option Time On
Distance 		Time On
Time
FinRating608.90.9855
FinRating, kevyt tuuli1111.60.8996
FinRating, kova tuuli477.01.0482
Custom scoring options for France
Scoring Option Time On
Distance 		Time On
Time
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Custom scoring options for Germany
Scoring Option Time On
Time
Coastal/Long Distance0.9855
Triple Number Coastal/Long Distance Low0.8113
Triple Number Coastal/Long Distance Medium1.0829
Triple Number Coastal/Long Distance High1.2288
Triple Number Windward/Leeward Low0.6308
Triple Number Windward/Leeward Medium0.8731
Triple Number Windward/Leeward High1.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
For information
General Purpose Handicap (GPH)630.8
Custom scoring options for Greece
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Saronikos S All Purpose648.70.9249
Saronikos S Upwind728.40.8237
Saronikos S Downwind554.51.0821
Saronikos N All Purpose673.40.8910
Saronikos N Upwind760.60.7888
Saronikos N Downwind598.71.0022
Saronikos SW All Purpose656.80.9135
Saronikos SW Upwind756.40.7933
Saronikos SW Downwind557.81.0757
Saronikos NE All Purpose704.70.8514
Saronikos NE Upwind718.30.8353
Saronikos NE Downwind677.70.8853
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Hungary
Scoring Option Time On
Distance 		Time On
Time
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Custom scoring options for Ireland
Scoring OptionTODTOT
Single Number All-Purpose582.81.0295
5-Band All Purpose Low903.90.6638
5-Band All Purpose L/M662.50.9056
5-Band All Purpose Med563.21.0653
5-Band All Purpose M/H509.51.1776
5-Band All Purpose High485.81.2351
Single Number Predominant Upwind603.00.9950
Single Number Predominant Reaching535.71.1200
Single Number Predominant Downwind571.81.0492
5-Band 50-50 Windward/Leeward Low1125.80.5329
5-Band 50-50 Windward/Leeward L/M807.60.7430
5-Band 50-50 Windward/Leeward Med673.50.8908
5-Band 50-50 Windward/Leeward M/H598.11.0032
5-Band 50-50 Windward/Leeward High565.21.0616
5-Band 60-40 Windward/Leeward Low1130.40.5308
5-Band 60-40 Windward/Leeward L/M815.90.7354
5-Band 60-40 Windward/Leeward Med685.10.8758
5-Band 60-40 Windward/Leeward M/H612.80.9791
5-Band 60-40 Windward/Leeward High582.81.0294
Triple Number 50-50 Windward/Leeward Low998.70.6008
Triple Number 50-50 Windward/Leeward Med687.30.8729
Triple Number 50-50 Windward/Leeward High588.31.0199
Scoring OptionTODTOT
Single Number 60-40 Windward/Leeward703.10.8533
Triple Number 60-40 Windward/Leeward Low1004.30.5974
Triple Number 60-40 Windward/Leeward Med698.40.8591
Triple Number 60-40 Windward/Leeward High603.80.9938
Triple Number All-Purpose Low807.30.7433
Triple Number All-Purpose Med573.11.0468
Triple Number All-Purpose High502.61.1939
Triple Number Predominant Upwind Low820.90.7309
Triple Number Predominant Upwind Med593.71.0106
Triple Number Predominant Upwind High530.81.1304
Triple Number Predominant Reaching Low731.10.8207
Triple Number Predominant Reaching Med533.01.1256
Triple Number Predominant Reaching High456.01.3158
Triple Number Predominant Downwind Low805.40.7450
Triple Number Predominant Downwind Med559.11.0731
Triple Number Predominant Downwind High471.31.2731
Custom scoring options for Israel
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Japan
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Korea
Scoring Option Time On
Distance
Triple Number Coastal/Long Distance Low739.6
Triple Number Coastal/Long Distance Medium554.1
Triple Number Coastal/Long Distance High488.3
Triple Number Windward/Leeward Low951.2
Triple Number Windward/Leeward Medium687.2
Triple Number Windward/Leeward High588.3
Predominantly Upwind604.0
Predominantly Downwind571.6
Predominantly Reaching545.6
Custom scoring options for Lithuania
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Netherlands
Scoring Option Time On
Time
Triple Number Coastal/Long Distance Low0.8113
Triple Number Coastal/Long Distance Medium1.0829
Triple Number Coastal/Long Distance High1.2288
Triple Number Windward/Leeward Low0.6308
Triple Number Windward/Leeward Medium0.8731
Triple Number Windward/Leeward High1.0199
Coastal/Long Distance0.9855
Predominantly Upwind0.9935
Predominantly Downwind1.0498
For information
General Purpose Handicap (GPH)630.8
Custom scoring options for Norway
Scoring Option Time On
Time
Distanseseilas Singeltall  (APH)1.0753
Distanseseilas Trippeltall svak vind0.8113
Distanseseilas Trippeltall mellomvind1.0829
Distanseseilas Trippeltall sterk vind1.2288
Pølsebane Trippeltall svak vind0.6308
Pølsebane Trippeltall mellomvind0.8731
Pølsebane Trippeltall sterk vind1.0199
Motvind Singeltall0.9935
Medvind Singeltall1.0498
Custom scoring options for Portugal
Scoring Option Time On
Distance 		Time On
Time
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Coastal/Long Distance608.90.9855
Custom scoring options for Russia
Scoring Option Time On
Distance 		Time On
Time
Predominantly Upwind604.00.9935
Predominantly Downwind571.61.0498
Custom scoring options for South Africa
Scoring Option Time On
Distance 		Time On
Time
Cape Doctor Inshore551.41.0882
Cape Doctor Coastal463.31.2951
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Custom scoring options for Slovenia
Scoring Option Time On
Time
Triple Number Coastal/Long Distance Low0.8113
Triple Number Coastal/Long Distance Medium1.0829
Triple Number Coastal/Long Distance High1.2288
Triple Number Windward/Leeward Low0.6308
Triple Number Windward/Leeward Medium0.8731
Triple Number Windward/Leeward High1.0199
Custom scoring options for Switzerland
Scoring Option Time On
Time
Triple Number Coastal/Long Distance Low0.8113
Triple Number Coastal/Long Distance Medium1.0829
Triple Number Coastal/Long Distance High1.2288
Triple Number Windward/Leeward Low0.6308
Triple Number Windward/Leeward Medium0.8731
Triple Number Windward/Leeward High1.0199
Custom scoring options for Sweden
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Predominantly Upwind604.00.9935
Predominantly Downwind571.61.0498
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for Ukraine
Scoring Option Time On
Distance 		Time On
Time
Coastal/Long Distance608.90.9855
Triple Number Coastal/Long Distance Low739.60.8113
Triple Number Coastal/Long Distance Medium554.11.0829
Triple Number Coastal/Long Distance High488.31.2288
Triple Number Windward/Leeward Low951.20.6308
Triple Number Windward/Leeward Medium687.20.8731
Triple Number Windward/Leeward High588.31.0199
Performance Curve4 kt 6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1543.31054.2796.4655.3571.2527.5496.8454.0442.0
Custom scoring options for United States of America
Scoring OptionTODTOT Scoring OptionTODTOT Scoring OptionTODTOT Single Number AP582.81.0295 Predom. Dn High457.51.3116 5B AP M/H494.61.2131 TriNum AP Low739.50.8113 Predom. Rc Low811.00.7399 5B AP High473.01.2684 TriNum AP Med554.11.0828 Predom. Rc L/M600.90.9984 5B SF Bay Low942.20.6368 TriNum AP High488.31.2288 Predom. Rc Med515.71.1634 5B SF Bay L/M767.60.7816 TriNum W/L Low998.70.6008 Predom. Rc M/H470.71.2748 5B SF Bay Med647.30.9269 TriNum W/L Med687.20.8731 Predom. Rc High450.11.3331 5B SF Bay M/H579.61.0352 TriNum W/L Hig588.31.0199 5B W/L Low1125.80.5329 5B SF Bay High550.81.0892 Predom. Upwind631.50.9502 5B W/L L/M807.60.7430 ChiMac Up Low785.70.7637 Predom. Reaching560.41.0706 5B W/L Med673.50.8908 ChiMac Up Med699.20.8581 Predom. Downwind600.40.9994 5B W/L M/H598.11.0032 ChiMac Up High599.71.0005 Predom. Up Low906.80.6617 5B W/L High565.21.0616 ChiMac Off Low770.80.7784 Predom. Up L/M674.60.8894 W/L 60-40 Low1130.40.5308 ChiMac Off Med673.70.8906 Predom. Up Med581.21.0323 W/L 60-40 L/M815.90.7354 ChiMac Off High561.41.0687 Predom. Up M/H532.91.1260 W/L 60-40 Med685.10.8758 ChiMac AP Low775.00.7742 Predom. Up High514.81.1655 W/L 60-40 M/H612.80.9791 ChiMac AP Med684.20.8770 Predom. Dn Low907.70.6610 W/L 60-40 High582.81.0294 ChiMac AP High579.11.0361 Predom. Dn L/M653.80.9177 5B AP Low828.00.7247 BayMac Cove Island894.80.6705 Predom. Dn Med547.31.0963 5B AP L/M637.80.9407 BayMac Shore887.90.6757 Predom. Dn M/H487.41.2311 5B AP Med544.91.1012 Harvest Moon489.91.2248      SA/DSPL Up18.25SA/DSPL Dn30.52
ORC Ref  04560004VKT Issued on 23/07/2026 Valid until 28/02/2027
VPP ver: 2026 1.00 | © ORC | www.orc.org
Club Certificate2026
THUNDERHEADUSA 75
US SAILING
1 ROGER WILLIAMS UNI WAY
BRISTOL, RI 02809
USA
Data in meters/kilograms (Metric)
HULL AND APPENDAGES (Lightship Trim)
ClassCustomMeasurement27/04/2026HINPlan reviewHull constructionSolidCarbon rudderNoLight stanchionsNoTrim tabNo
Length overall14.399Maximum beam3.980Draft3.061Displacement17,831Wetted area44.24IMS L11.517LSM011.310Accomod. length12.935Sink (kg/mm) 30.48
VCGD0.026VCGM-0.072 RM Rated (kg·m) 318.0Limit of positive stability(°) 119.5 Stability Index 130.0 BLR index 0.0000Default crew weight820 Declared crew weight 953
Centerboard weight356.2List angleCanting keel angle
PROPELLER
Propeller TypeFeathering 3 blades
InstallationIn ApertureTwin screwNoHydro generatorNo
PRD0.518PBWPIPA0.0188
APH0.900APT0.300APB0.400
RIG
BackstayAdjustableForestayFixedInner forestayFixedMast materialWoodSingle headsail furlerNoMainsail furlerNoArticulated bowspritNoNon-circular riggingNoFiber riggingNoBase of mastFixedRunning backstaysNoCheckstaysYesSpreaders2Rotating mastNo
P15.150IG17.120ISP17.210MDT10.170MDL10.310MDT20.122MDL20.214TL4.900MW0.198GO0.223
E5.960J5.945BAS1.510FSD0.035SFJ0.350SPLWPLTPS6.070BD0.176MWTMCG
PYMDT1YMDL1YMDT2YMDL2YTLYBASYEYBDYIYEB
Flying Headsail Foretriangles IdISPTPS
FLOTATION AND STABILITY
Calculation methodPoles incliningFlotation Date27/04/2026CommentCalm, 2-4 kts
SFFP1.518FFM1.535FF1.544LCFcl8.203SG1.0160
SAFP13.716FAM0.927FA0.945LCFsh8.464HBI1.136
W1158.6W2158.6W3158.6W4158.6
PD1476.1PD2476.1PD3476.1PD4476.1
WD12.255PLM9000.00GSA1.0RSA1.0RM321.5
INVENTORY
Fixed Ballast Total0
TANKSIdDescriptionSp.WghtCapacityConditionLCGVCG4SS Water Tank, PortWater8308.00-0.603SS Water Tank, StbdWater8308.00-0.602SS Fuel Tank, PortFuel1511518.90-0.601SS Fuel Tank, StbdFuel1511518.90-0.60Total deductible2548.90-0.60
OTHER ITEMSIdKindDescriptionWeightLCGVCG3Battery2X Starter Batteries, 12V AGM, Lifeline GPL-2700T5810.900.002Battery4X House Batteries, 12V AGM, Lifeline GPL-4DL2846.80-0.501Engine (IC)Total deductible0
ORC Ref  04560004VKT Issued on 23/07/2026 Valid until 28/02/2027
VPP ver: 2026 1.00 | © ORC | www.orc.org
Club Certificate2026
THUNDERHEADUSA 75
US SAILING
1 ROGER WILLIAMS UNI WAY
BRISTOL, RI 02809
USA
MAINSAIL
IdMHBMUWMTWMHWMQWAreaMeas.DateCommentMn0.150.981.833.354.6548.7809/03/2026
HEADSAIL
IdHHBHUWHTWHHWHQWHLPHLUBtnFlyingFTAreaMeas.DateCommentHSF0.082.384.736.167.288.1416.28NoYes088.1911/03/2026M10.071.232.414.747.049.3016.34NoNo 76.9719/01/202613707Genoa0.060.941.783.785.817.9516.23NoNo 62.6309/03/2026Yankee0.060.500.961.953.064.3116.16NoNo 33.1209/03/2026GS0.050.340.671.392.203.1411.50NoInner 16.9309/03/2026SJ1.222.857.06NoInner 9.8710/03/2026
ASYMMETRIC SPINNAKER
IdSLUSLESLSHWSFLRatioAreaMeas.DateCommentA-17518.8217.1217.9710.7610.8999%161.5226/01/202613708
NON MANUAL POWER CONTROLS (NMP)
SheetsNoMainsail cunninghamNoJib trackNoSpinnaker retrieverNoBoomvangNoHeadsail cunninghamNoTack lineNoOuthaulNoMain travellerNoHalyardsNo
CRUISER/RACER REQUIREMENTS*
Accommodation length12.9 mTable area0.66 m²Headroom1.85 mMinimum number of berths6Personal gear stowage0.24 m³Fresh water capacity207 lMinimum number of seats in cockpit6Food stowage0.36 m³Fuel capacity108 lCabin soleStovesSinksGalley gear stowageToiletWash basinNavigation areaHanging locker
*This list is a summary of the requirements. See IMS Appendix 1 for details.
ORC Ref  04560004VKT Issued on 23/07/2026 Valid until 28/02/2027
VPP ver: 2026 1.00 | © ORC | www.orc.org