How to Calculate Results using Portsmouth Numbers

Use Portsmouth Handicap Numbers to calculate finish positions as corrected time for boats that are not alike and compete together on a common course for an unspecified distance. The Portsmouth Handicap Number of a boat assumes that each boat is sailed to its true potential by a perfect crew using flawless strategy, and that all boats and sails conform to class specifications and rules. Courses sailed may be triangular, modified Gold Cup, Olympic, or windward-leeward.

The Race Committee records:
• wind speed at the beginning, middle, and end of the race
• exact start time of the race
• exact finish time for every boat

To score the race the Race Committee:
• averages the 3 recorded wind velocities and selects the corresponding Beaufort Number range to use as the wind handicap number in the formula for GSBYRA, or instead uses the basic Portsmouth Number D-PN - see Beaufort Scale of Wind Velocity table below
• determines elapsed time for every boat
• converts elapsed time into decimal minutes for use in the formula - refer to conversion table below
• uses the formula CT=(ET X 100)/HC to calculate corrected times - use the Portsmouth Handicap Worksheet and refer to handicap tables below
            CT is corrected time
            ET is elapsed time
            HC is either the recommended Wind Handicap Number or the basic D-PN
• converts decimal time into hour, minutes, and seconds - refer to conversion table below
• arranges finish order with the lowest corrected time in first place

Beaufort Scale of Wind Velocity:

Beaufort Numbers characterize weather conditions. Use a meter to determine wind velocities and note that subjective annotations of sea conditions over force 5 do not apply on Great South Bay.

Beaufort Wind Velocity:   Seamans Wave Sea Conditions
Number
(Knots)
 (MPH) Term Height  
0
 0-1 0-1.7 Calm Smooth Glassy, mirrorlike
1
 2-3 1.8-4.0 Light air Ripples Scale-like ripple
2
 4-6 4.1-7.4 Light breeze 1/3 ft. Small wavelets
3
 7-10 7.5-12.0 Gentle breeze 1-2 ft. Large wavelets, crest begins to break
4
 11-16 12.1-18.9 Moderate breeze 2-3 ft. Small waves, some whitecaps
5
 17-21 19.0-24.7 Fresh breeze 3-4 ft. Longer waves, many whitecaps
6
 22-27 24.8-31.6 Strong breeze 4-5 ft. Large waves, many whitecaps, foam & spray everywhere
7
 28-33 31.7-38.5 Moderate gale 5-6 ft. Sea heaps up, streaks of foam
8
 34-40 38.6-46.6 Fresh gale 6-7 ft. High long waves, spindrift
9
 41-47 46.7-53.3 Strong gale 7-9 ft. Rolling seas

Seconds to Decimal Minute conversion:

  Dec.     Dec.     Dec.     Dec.     Dec.     Dec.
Sec. Min.   Sec. Min.   Sec. Min.   Sec. Min.   Sec. Min.   Sec. Min.
1
.02
11
.18
21
.35
31
.52
41
.68
51
.85
2
.03
12
.20
22
.37
32
.53
42
.70
52
.87
3
.05
13
.22
23
.38
33
.55
43
.72
53
.88
4
.07
14
.23
24
.40
34
.57
44
.73
54
.90
5
.08
15
.25
25
.42
35
.58
45
.75
55
.92
6
.10
16
.27
26
.43
36
.60
46
.77
56
.93
7
.12
17
.28
27
.45
37
.62
47
.78
57
.95
8
.13
18
.30
28
.47
38
.63
48
.80
58
.97
9
.15
19
.32
29
.48
39
.65
49
.82
59
.98
10
.17
20
.33
30
.50
40
.67
50
.83

Centerboard Boats:

Class
D-PN
BN 0-1
BN 2-3
BN 4
BN 5
29er
84.5
85.8
84.7
83.9
78.9
420 Club
97.6
103.4
100.0
95.0
90.8
470 International
96.3
91.4
88.4
85.0
82.1
 
Blue Jay
108.6
110.1
109.5
107.2
106.7
Bucaneer 18
86.9
89.2
87.0
86.3
85.4
Byte
97.4
97.7
97.4
96.3
95.3
 
Cape Cod Mercury CB
107.0
-
-
-
-
Contender
90.1
95.9
91.0
82.0
-
Day Sailor O'Day 17
98.5
101.3
98.5
96.9
96.3
 
Fireball
85.6
87.9
87.1
85.4
82.4
Flying Junior
97.9
100.9
99.3
98.2
95.8
Flying Scot
89.6
92.1
90.4
89.1
87.5
 
Force 5
95.4
98.1
96.6
95.3
93.4
Herreshoff America 18
116.9
-
117.0
115.6
-
Holder 14
111.0
113.3
111.7
108.4
-
 
JY 15
91.9
92.5
92.4
91.9
-
Laser
91.1
93.7
92.3
91.0
88.2
Laser 4.7
95.4
96.1
95.2
94.9
-
 
Laser Radial
96.7
99.4
97.3
93.6
-
Laser Pico Uno
104.6
-
104.5
-
-
Lightning
87.0
92.6
87.6
85.4
83.9
 
Mariner 19 CB
102.1
105.0
103.1
100.3
99.0
Marshall 15 Sandpiper
112.7
116.6
114.3
109.1
-
Marshall 18 Sanderling
104.5
107.5
105.0
102.2
-
 
Marshall 22
96.6
-
-
-
-
Mobjack
91.3
96.5
92.4
88.0
86.5
Narrasketuck
89.7
89.0
89.0
89.0
85.0
 
Optimist
123.6
-
124.0
-
-
Orion 19 Sailstar
111.5
-
111.9
-
-
Raven
83.0
85.2
83.0
81.5
81.0
P Boat
76.3
80.1
78.4
74.6
72.6
 
Rhodes 19 CB
95.8
100.0
97.0
92.2
90.7
Sunfish
99.6
103.0
100.4
97.8
95.8
Tanzer 22 CB
96.0
99.0
97.2
95.3
93.1
           
Thistle
83.0
83.0
83.0
83.0
83.0
Vanguard 15
90.5
92.6
91.2
86.1
-
Windmill
89.5
92.9
91.4
88.3
86.2
Wood Pussy
103.0
-
104.9
99.3
-
           
All centerboard classes          
Inactive cb classes          

Keelboat and Offshore Boats:

For GSBYRA events, a PHRF Class boat is defined as a boat with length overall of twenty feet or greater, and designed with sleeping accommodations. Boats that meet these specifications shall race in the PHRF Class. Boats that do not meet the specifications for the PHRF Class shall race in the Monohull Handicap Class and be scored with Portsmouth Number ratings.

Class
D-PN
BN 0-1
BN 2-3
BN 4
BN 5
Bristol 35
89.3
-
88.0
97.4
-
Cape Dory 27
93.8
94.5
93.9
90.6
-
Catalina 27
87.4
90.5
88.1
96.1
85.0
 
Catalina Capri 22
90.8
92.6
91.5
90.1
89.0
C & C 25
91.5
95.0
91.8
90.6
88.1
Herreshoff 12 1/2
110.9
114.7
112.2
109.7
109.7
 
Hobie Magic
65.4
-
63.4
-
-
Holder 20
85.8
88.2
87.8
85.7
81.7
J 22 Class Jib
82.7
84.2
82.7
82.2
82.0
 
J 22 Open
81.7
82.6
81.6
81.5
81.0
J 24
80.8
83.3
81.9
80.4
78.0
J 27
77.1
79.7
78.1
75.4
74.6
 
J 30
76.9
78.7
78.3
76.2
73.9
Mercury CC (Keel)
105.0
-
-
-
-
Morgan 30
86.8
92.0
87.5
83.7
80.5
 
O' Day 222
98.3
99.9
99.1
97.3
-
O' Day 23 Deckstep
98.6
99.3
98.9
98.7
98.3
O' Day 23 Keel Step
99.1
99.3
99.0
98.1
97.5
 
O' Day 25 spin
95.2
97.4
95.7
95.0
93.6
O' Day 25 CB spin
95.4
97.8
95.4
94.3
94.2
O' Day 25 T mast FK spin
92.8
93.6
93.0
-
-
 
O' Day 272 WK
93.6
94.2
93.6
91.4
-
O' Day 322 WK
82.9
-
83.0
87.6
-
Rhodes 19 (Keel)
96.9
100.9
99.0
94.2
92.9
 
Sabre 28
90.1
92.0
90.6
89.2
-
Star
83.1
83.9
86.3
82.4
81.5
Tartan 27
95.3
97.5
95.3
94.6
94.0
Tartan 34
84.3
86.2
84.9
82.8
81.0
           
All Keelboat Classes          
Offshore Classes A - E          
Offshore Classes F - N          
Offshore Classes O - Z          

South Bay Cruising Club is a recognized handicapping authority of US SAILING. PHRF Handicap forms are available on the Forms page. For GSBYRA each PHRF skipper is obligated to obtain a Handicap form in advance and submit the form to the SBCC Handicap Chairperson Bill Danilczyk at wjdanilczyk@aol.com at least 7 days prior to the yacht’s first race in order to be scored. US SAILING determined a difference of 1 D-PN equals a difference of 6 seconds PHRF. Use the formula D-PN = PHRF / 6 + 55.

Multihull Boats:

Class
D-PN
BN 0-1
BN 2-3
BN 4
BN 5
Condor 40
61.2
-
-
-
-
Dragonfly 800
71.8
75.2
72.0
71.5
70.6
Dragonfly 920
68.2
-
-
-
-
 
F-24 Tri Mk I
76.1
79.9
76.9
75.6
74.5
F-27 Tri
70.5
72.4
73.0
71.4
65.1
Hobie 14
86.4
95.0
90.1
85.6
80.9
 
Hobie 14 Turbo
83.1
86.3
85.1
81.1
79.4
Hobie 16
76.0
81.5
78.7
74.1
71.3
Hobie 17
74.0
78.3
76.2
73.7
69.7
 
Hobie 18 & 18 Magnum
71.4
76.8
73.5
69.5
66.8
Hobie 20 Miracle (orig)
65.0
69.1
66.4
64.4
61.4
Hobie 20 (mod) no spin
63.7
67.0
64.7
63.1
60.5
Hobie 20 (mod) with spin
61.4
65.3
62.7
60.8
58.0
Hobie 21 no spinnaker
67.0
71.9
69.2
66.3
61.7
 
Inter 20 with spinnaker
59.3
61.9
60.2
58.5
57.6
NACRA 5.0 2-trapeze
77.0
80.5
78.5
76.2
73.0
NACRA 5.2 sloop-2 trap
72.1
78.0
74.8
71.6
67.4
 
NACRA 5.5 sloop
67.0
73.5
69.5
65.7
61.2
NACRA 5.5 uni 8.5
69.7
74.4
71.9
69.0
64.5
NACRA 5.7 2-trapeze
72.6
75.5
74.8
72.2
68.6
 
NACRA 5.8 original 2-tra
66.6
72.1
69.3
65.7
62.2
NACRA 5.8 N.A.
65.5
70.4
68.5
65.4
62.0
NACRA 6.0 N.A.
62.6
65.4
64.3
61.9
59.5
 
Pacific Cat
73.7
80.6
76.0
75.0
69.5
Prindle 16
77.5
84.1
80.7
76.3
71.3
Prindle 18
74.8
81.0
77.8
74.7
70.5
 
Prindle 18-2
69.1
82.6
71.7
68.7
65.1
Prindle 19
66.4
71.7
68.9
64.5
62.3
Stiletto 27
74.8
79.0
76.6
75.4
69.5
 
Supercat 20
65.0
70.4
67.3
65.2
60.8
Tornado classic 1-trap
63.9
67.0
65.6
63.1
60.6
Tornado Internatational: 2-trap and spinnaker
59.0
62.2
60.5
57.8
55.5
 
           
All multihull classes          
Inactive multihull classes