Club
Certificate
2024

Boat

AKRA

ESP-10811_C

RFEV
c/ Gamazo sn
39004 Santander – España
crucero@rfev.es
Rated boat velocities in knots
Wind Velocity6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Beat Angles45.4°43.6°42.3°40.8°39.5°39.2°39.6°41.0°
Beat VMG2.973.634.134.514.754.864.884.75
52°4.615.546.176.556.786.927.016.97
60°4.905.826.406.746.967.127.267.27
75°5.086.006.576.917.157.377.707.82
90°5.136.176.807.167.437.627.938.28
110°5.186.256.887.297.678.048.679.11
120°5.006.086.787.217.618.018.849.91
135°4.505.596.426.947.337.728.539.66
150°3.834.875.716.336.747.057.638.24
Run VMG3.314.224.945.485.846.377.097.66
Gybe Angles144.8°146.9°147.1°147.8°150.2°173.8°176.8°176.5°
APH ToD:609.8CDL: 8.003APH ToT: 0.9839CertNo:108111
BOAT
ClassOCEANIS 311DesignerFINOTBuilderBENETEAUAge date01/2002Series date01/2002Offset fileOcean311.OFFData fileE10811_C
HULL
Length Overall9.540 mMaximum Beam3.234 mDraft1.454 mDisplacement3,969 kgDLR5.4715IMS DivisionCruiser/RacerDynamic Allowance0.330%Age Allowance0.487%
PROPELLER
InstallationShaft non exposedTypeSolid 2 bladesDiameter0.280m
CREW
Maximum weight591 kg(default)Minimum weight461 kg * when appliedNon Manual PowerNoCrew Arm Extension
SAIL AREAS (m²)
MeasuredRatedMainsail25.5525.95Headsail Luffed23.0523.05Headsail FlyingSymmetricAsymmetric62.3362.33 (All asymmetric spinnakers with SHW/SFL > 85%)
STORM SAIL AREAS (m²)
Trysail7.84Storm Jib7.84Heavy Weather Jib21.17
SAIL LIMITS
Headsails5 * Woven polyester sails  Spinnakers4
STABILITY
Righting MomentN/AStability IndexN/A
COMMENTS
CASCO ESTIMADO
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.

Club
Certificate
2024

Boat

AKRA

ESP-10811_C

RFEV
c/ Gamazo sn
39004 Santander – España
crucero@rfev.es
Time Allowances in secs/NM
Wind Velocity6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Beat VMG1214.0990.9871.6799.0757.4741.3738.0757.2
52°780.2649.4583.8549.8530.7519.9513.9516.5
60°734.2618.1562.7534.2517.0505.4495.8495.3
75°708.9600.1547.7521.2503.2488.4467.8460.5
90°701.9583.3529.8502.7484.4472.7454.1434.6
110°695.5575.9523.2493.8469.1448.0415.3395.2
120°719.6591.9531.2499.2472.8449.3407.3363.4
135°799.2643.6560.6518.8491.3466.6422.3372.7
150°941.2739.5630.5568.8534.2510.6471.9436.8
Run VMG1086.8853.9728.1656.8616.8565.3507.9469.8
Selected Courses
Windward / Leeward1150.4922.4799.8727.9687.1653.3623.0613.5
All purpose881.7718.1634.0586.9558.3537.4512.9498.4
Single Number Scoring Options
CourseTime On
Distance
Time On
Time
Windward / Leeward762.00.7874
All purpose609.80.9839
 
Custom scoring options for Australia
Scoring OptionTime On
Distance
Time On
Time
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Custom scoring options for Austria
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Brazil
Scoring OptionTime On
Time
Upwind "bolina"0.6871
Downwind "popa"0.8374
70% up, 30% down "Ilhabela"0.7262
30% up, 70% down "Ilhabela-inverso"0.7859
Custom scoring options for Bulgaria
Scoring OptionTime On
Distance
Time On
Time
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Predominantly Upwind662.10.9062
Predominantly Downwind619.20.9691
Custom scoring options for Canada
Scoring OptionTODTOT
Triple Number AP Low799.90.7501
Triple Number AP Medium606.50.9893
Triple Number AP High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Predominant Upwind661.30.9074
Predominant Reaching589.71.0174
Predominant Downwind589.71.0174
Predominant Upwind - Low895.40.6701
Predominant Upwind - Low/Med738.30.8127
Predominant Upwind - Medium638.50.9397
Predominant Upwind - Med/High585.71.0244
Predominant Upwind - High568.01.0564
Predominant Downwind Low781.20.7680
Predominant Downwind Low/Med702.30.8544
Predominant Downwind Medium596.81.0054
Predominant Downwind Med/High530.71.1306
Predominant Downwind High491.01.2220
Predominant Reaching Low781.20.7680
Predominant Reaching Low/Med644.90.9304
Predominant Reaching Medium560.11.0713
Predominant Reaching Med/High510.91.1743
Predominant Reaching High483.51.2409
SA/DSPL Upwind19.30SA/DSPL Downwind34.89
Scoring OptionTODTOT
5-Band Windward/Leeward Low1098.60.5461
5-Band Windward/Leeward Low/Med884.10.6787
5-Band Windward/Leeward Medium743.10.8074
5-Band Windward/Leeward Med/High660.30.9087
5-Band Windward/Leeward High626.60.9576
Windward/Leeward 60-40 Low1111.60.5398
Windward/Leeward 60-40 Low/Med897.90.6682
Windward/Leeward 60-40 Medium757.50.7920
Windward/Leeward 60-40 Med/High677.90.8851
Windward/Leeward 60-40 High649.60.9236
5-Band AP Low844.50.7104
5-Band AP Low/Med693.20.8655
5-Band AP Medium596.81.0054
5-Band AP Med/High541.01.1091
5-Band AP High514.61.1659
5-Band SF Bay Tour - Low1046.10.5735
5-Band SF Bay Tour - Low/Med845.70.7095
5-Band SF Bay Tour - Medium714.70.8396
5-Band SF Bay Tour - Med/High640.20.9373
5-Band SF Bay Tour - High610.80.9823
Chicago-Mac Upwind0.8865
Chicago-Mac All Purpose0.9166
Chicago-Mac Downwind0.9519
Bayview-Mac Cove Island0.8462
Bayview-Mac Shore0.8535
Harvest Moon Regatta524.41.1442
Custom scoring options for Cyprus
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Denmark
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Spain
Scoring OptionTime On
Distance
Coastal/Long Distance666.4
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Estonia
Scoring OptionTime On
Distance
Time On
Time
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Custom scoring options for Finland
Scoring OptionTime On
Distance
Time On
Time
FinRating (Coastal/Long Distance)666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for France
Scoring OptionTime On
Distance
Time On
Time
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Custom scoring options for Germany
Scoring OptionTime On
Time
Triple Number Coastal/Long Distance Low0.7501
Triple Number Coastal/Long Distance Medium0.9894
Triple Number Coastal/Long Distance High1.1248
Triple Number Windward/Leeward Low0.5789
Triple Number Windward/Leeward Medium0.7917
Triple Number Windward/Leeward High0.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Greece
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Hungary
Scoring OptionTime On
Distance
Time On
Time
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Custom scoring options for Israel
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Japan
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Korea
Scoring OptionTime On
Distance
Triple Number Coastal/Long Distance Low799.9
Triple Number Coastal/Long Distance Medium606.4
Triple Number Coastal/Long Distance High533.4
Triple Number Windward/Leeward Low1036.4
Triple Number Windward/Leeward Medium757.9
Triple Number Windward/Leeward High650.3
Predominantly Upwind662.1
Predominantly Downwind619.2
Predominantly Reaching589.7
Custom scoring options for Lithuania
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Netherlands
Scoring OptionTime On
Time
Triple Number Coastal/Long Distance Low0.7501
Triple Number Coastal/Long Distance Medium0.9894
Triple Number Coastal/Long Distance High1.1248
Triple Number Windward/Leeward Low0.5789
Triple Number Windward/Leeward Medium0.7917
Triple Number Windward/Leeward High0.9226
Coastal/Long Distance0.9004
Predominantly Upwind0.9062
Predominantly Downwind0.9691
For information
General Purpose Handicap (GPH)687.9
Custom scoring options for Norway
Scoring OptionTime On
Time
Tretall Distanseseilas Lite vind0.7501
Tretall Distanseseilas Mellomvind0.9894
Tretall Distanseseilas Mye vind1.1248
Tretall Pølsebane Lite vind0.5789
Tretall Pølsebane Mellomvind0.7917
Tretall Pølsebane Mye vind0.9226
Distanseseilas ett tall (OSN 8-16kn)0.9004
Distanseseilas ett tall (APH 6-20kn)0.9839
Enkeltall Motvind0.9062
Enkeltall Medvind0.9691
Custom scoring options for Portugal
Scoring OptionTime On
Distance
Time On
Time
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Coastal/Long Distance666.40.9004
Custom scoring options for Russia
Scoring OptionTime On
Distance
Time On
Time
Predominantly Upwind662.10.9062
Predominantly Downwind619.20.9691
Custom scoring options for South Africa
Scoring OptionTime On
Distance
Time On
Time
Cape Doctor Inshore616.40.9735
Cape Doctor Coastal502.81.1934
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Custom scoring options for Slovenia
Scoring OptionTime On
Time
Triple Number Coastal/Long Distance Low0.7501
Triple Number Coastal/Long Distance Medium0.9894
Triple Number Coastal/Long Distance High1.1248
Triple Number Windward/Leeward Low0.5789
Triple Number Windward/Leeward Medium0.7917
Triple Number Windward/Leeward High0.9226
Custom scoring options for Switzerland
Scoring OptionTime On
Time
Triple Number Coastal/Long Distance Low0.7501
Triple Number Coastal/Long Distance Medium0.9894
Triple Number Coastal/Long Distance High1.1248
Triple Number Windward/Leeward Low0.5789
Triple Number Windward/Leeward Medium0.7917
Triple Number Windward/Leeward High0.9226
Custom scoring options for Sweden
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Predominantly Upwind662.10.9062
Predominantly Downwind619.20.9691
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for Ukraine
Scoring OptionTime On
Distance
Time On
Time
Coastal/Long Distance666.40.9004
Triple Number Coastal/Long Distance Low799.90.7501
Triple Number Coastal/Long Distance Medium606.40.9894
Triple Number Coastal/Long Distance High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Performance Curve6 kt 8 kt 10 kt 12 kt 14 kt 16 kt 20 kt 24 kt
Coastal/Long Distance1144.0864.6717.5628.8580.4543.2488.4468.0
Custom scoring options for United States of America
Scoring OptionTODTOT
Triple Number AP Low799.90.7501
Triple Number AP Medium606.50.9893
Triple Number AP High533.41.1248
Triple Number Windward/Leeward Low1036.40.5789
Triple Number Windward/Leeward Medium757.90.7917
Triple Number Windward/Leeward High650.30.9226
Predominant Upwind661.30.9074
Predominant Reaching589.71.0174
Predominant Downwind589.71.0174
Predominant Upwind - Low895.40.6701
Predominant Upwind - Low/Med738.30.8127
Predominant Upwind - Medium638.50.9397
Predominant Upwind - Med/High585.71.0244
Predominant Upwind - High568.01.0564
Predominant Downwind Low781.20.7680
Predominant Downwind Low/Med702.30.8544
Predominant Downwind Medium596.81.0054
Predominant Downwind Med/High530.71.1306
Predominant Downwind High491.01.2220
Predominant Reaching Low781.20.7680
Predominant Reaching Low/Med644.90.9304
Predominant Reaching Medium560.11.0713
Predominant Reaching Med/High510.91.1743
Predominant Reaching High483.51.2409
SA/DSPL Upwind19.30SA/DSPL Downwind34.89
Scoring OptionTODTOT
5-Band Windward/Leeward Low1098.60.5461
5-Band Windward/Leeward Low/Med884.10.6787
5-Band Windward/Leeward Medium743.10.8074
5-Band Windward/Leeward Med/High660.30.9087
5-Band Windward/Leeward High626.60.9576
Windward/Leeward 60-40 Low1111.60.5398
Windward/Leeward 60-40 Low/Med897.90.6682
Windward/Leeward 60-40 Medium757.50.7920
Windward/Leeward 60-40 Med/High677.90.8851
Windward/Leeward 60-40 High649.60.9236
5-Band AP Low844.50.7104
5-Band AP Low/Med693.20.8655
5-Band AP Medium596.81.0054
5-Band AP Med/High541.01.1091
5-Band AP High514.61.1659
5-Band SF Bay Tour - Low1046.10.5735
5-Band SF Bay Tour - Low/Med845.70.7095
5-Band SF Bay Tour - Medium714.70.8396
5-Band SF Bay Tour - Med/High640.20.9373
5-Band SF Bay Tour - High610.80.9823
Chicago-Mac Upwind0.8865
Chicago-Mac All Purpose0.9166
Chicago-Mac Downwind0.9519
Bayview-Mac Cove Island0.8462
Bayview-Mac Shore0.8535
Harvest Moon Regatta524.41.1442

Club
Certificate
2024

Boat

AKRA

ESP-10811_C

RFEV
c/ Gamazo sn
39004 Santander – España
crucero@rfev.es
Data in meters/kilograms (Metric)
HULL AND APPENDAGES (Lightship Trim)
ClassOCEANIS 311Measurement11/01/2021HINPlan reviewHull constructionSolidCarbon RudderNoLight stanchionsNoTrim tabNo
LOA9.540Max. Beam3.234Draft1.454Displacement3,969Wetted area20.37IMS L9.019LSM08.985Acc. length9.540Sink (kg/mm) 16.20
VCGD-0.071VCGM-0.086RM Rated (kg·m) 98.6Limit of positive stability(°) N/AStability IndexN/ADefault crew weight591Declared crew weightN/A
PROPELLER
Propeller TypeSolid 2 blades
InstallationShaft non exposedTwin screwNoHydro generatorNo
PRD0.280PBWPIPA0.0039
PSD0.025PHD0.040PHL0.060
PSAESL
RIG
Forestay tensionAftInner stayNone FittedMast materialAluminumSingle headsail furlerNoMainsail furlerNoArticulated bowspritNoNon-circular riggingNoFiber riggingNoAdjustable mast footNoRunners/Checkstays0Spreaders1Rotating mastNo
P11.200IG12.520ISP12.520MDT10.100MDL10.110MDT2MDL2TLMWGO
E4.000J3.430BAS1.600FSD0.050SFJ0.078SPLWPLTPS3.920BD0.130MWTMCG
Flying Headsail Foretriangles IdISPTPS
FLOTATION AND STABILITY
Calculation methodRM entered directlyRM entered100.0Flotation Date01/01/2010
BALLAST
TANKS
INVENTORY
INVENTORY
Fixed Ballast Total0
Total deductible
Total deductible

Club
Certificate
2024

Boat

AKRA

ESP-10811_C

RFEV
c/ Gamazo sn
39004 Santander – España
crucero@rfev.es
MAINSAIL
IdMHBMUWMTWMHWMQWAreaMeas.DateComment10.110.731.352.433.2925.5511/01/2021
HEADSAIL
IdHHBHUWHTWHHWHQWHLPHLUBtnFlyingFTAreaMeas.DateComment10.060.450.871.852.954.0611.88YesNo 23.0511/01/2021
ASYMMETRIC SPINNAKER
IdSLUSLESLSHWSFLRatioAreaMeas.DateComment113.1511.8412.505.806.7386%62.3311/01/2021
CRUISER/RACER REQUIREMENTS*
Accommodation length9.5 mTable area0.44 m²Headroom1.67 mMinimum number of berths4Personal gear stowage0.16 m³Fresh water capacity70 lMinimum number of seats in cockpit4Food stowage0.24 m³Fuel capacity40 l
*This list refers to the calculated requirements. See IMS Appendix 1 for the complete list of requirements.