| West Wight Potter Owner's Association Harry Gordon ___________________________________________________________________________________________ |
Sail Dimensions for Early Potters
(U.S. gunter rigs and “Mk I’s” and UK “A-types” and B-types)
Harry Gordon, WWP #234, June 13, 2005
Someone on the Trailer Sailor Potter Forum needed the sail measurements for an early
gunter-rigged Potter. The original sails for my 1967 gunter-rigged U.S. West Wight Potter
were still in fair condition, so I laid them out on the lawn and measured them.
Here are the results. I used an on-line triangle calculator to determine the triangle areas
and tack angles.
Note that I measured the sails corner to corner as they lay. If I had pulled them tight from
corner to corner I would probably have gained an inch or two on each one. I included the
triangular area of the main roach but disregarded any other rounding or fullness that
would have added to the total area. Thus my calculated triangles total less area than the
advertised sail area.
Jib
Luff: 120" (10')
Foot: 51" (4'3")
Leach: 98" (8'2")
Calculated tack angle: 52.8 deg
Calculated triangle area: 16.9 sq ft
Advertised sail area: 20 sq ft
Main
Luff: 147" (12'3")
Foot: 93" (7'9")
Leach: 171" (14'3")
Roach: approx 1' at mid-leach
Calculated tack angle: 87.9 deg
Calculated triangle area: 6831 sq in
Plus roach triangle area: 85.5 sq in =
Combined triangle sail area: 6916 sq in (48.2 sq ft)
Advertised main sail area: 52 sq ft
The advertised sail area for the UK original WWP (now called the “A-type”), the UK B-
type, both versions of the U.S. gunter-rigged Potters, and the first non-gunter U.S. P14s
(now referred to as the “Mk I”) was the same, i.e., main, 52 sq ft; jib, 20 sq ft. It appears
the sail dimensions were approximately the same also.
The gunter rig sails had bolt rope in the foot and luff to fit in the grooved wooden spars.
The Mk I main was set loose footed on an aluminum spar like the later, larger Mk II main,
so it had bolt rope only in the luff (for the grooved aluminum mast), not in the foot.
The classic “WWP” sail emblem was used only on the gunter rigs; the “Mk I” was the first
to use the (HMS Marine/International Marine) spinnaker emblem used on all U.S. Potters
since then. My sail had a black emblem and red numbers, although. I’ve seen photos of
gunter Potters with red emblems and black numbers.
Harry Gordon
h.gordon@comcast.net
(U.S. gunter rigs and “Mk I’s” and UK “A-types” and B-types)
Harry Gordon, WWP #234, June 13, 2005
Someone on the Trailer Sailor Potter Forum needed the sail measurements for an early
gunter-rigged Potter. The original sails for my 1967 gunter-rigged U.S. West Wight Potter
were still in fair condition, so I laid them out on the lawn and measured them.
Here are the results. I used an on-line triangle calculator to determine the triangle areas
and tack angles.
Note that I measured the sails corner to corner as they lay. If I had pulled them tight from
corner to corner I would probably have gained an inch or two on each one. I included the
triangular area of the main roach but disregarded any other rounding or fullness that
would have added to the total area. Thus my calculated triangles total less area than the
advertised sail area.
Jib
Luff: 120" (10')
Foot: 51" (4'3")
Leach: 98" (8'2")
Calculated tack angle: 52.8 deg
Calculated triangle area: 16.9 sq ft
Advertised sail area: 20 sq ft
Main
Luff: 147" (12'3")
Foot: 93" (7'9")
Leach: 171" (14'3")
Roach: approx 1' at mid-leach
Calculated tack angle: 87.9 deg
Calculated triangle area: 6831 sq in
Plus roach triangle area: 85.5 sq in =
Combined triangle sail area: 6916 sq in (48.2 sq ft)
Advertised main sail area: 52 sq ft
The advertised sail area for the UK original WWP (now called the “A-type”), the UK B-
type, both versions of the U.S. gunter-rigged Potters, and the first non-gunter U.S. P14s
(now referred to as the “Mk I”) was the same, i.e., main, 52 sq ft; jib, 20 sq ft. It appears
the sail dimensions were approximately the same also.
The gunter rig sails had bolt rope in the foot and luff to fit in the grooved wooden spars.
The Mk I main was set loose footed on an aluminum spar like the later, larger Mk II main,
so it had bolt rope only in the luff (for the grooved aluminum mast), not in the foot.
The classic “WWP” sail emblem was used only on the gunter rigs; the “Mk I” was the first
to use the (HMS Marine/International Marine) spinnaker emblem used on all U.S. Potters
since then. My sail had a black emblem and red numbers, although. I’ve seen photos of
gunter Potters with red emblems and black numbers.
Harry Gordon
h.gordon@comcast.net