The Rock 20 is a 23.52ft masthead sloop designed by Heinz-Jurgen Sass and built in fiberglass by Birka Marine (FIN) between 1968 and 1975.
200 units have been built.
The Rock 20 is a moderate weight sailboat which is slightly under powered. It is reasonably stable / stiff and has a good righting capability if capsized. It is best suited as a coastal cruiser.
Main features
| Model | Rock 20 | ||
| Length | 23.52 ft | ||
| Beam | 7.38 ft | ||
| Draft | 3.94 ft | ||
| Country | Finland (Europe) | ||
| Estimated price | $ 0 | ?? |
Ratios
| Sail area / displ. | 14.15 | ||
| Ballast / displ. | 34.29 % | ||
| Displ. / length | 231.57 | ||
| Comfort ratio | 20.07 | ||
| Capsize | 1.88 |
Hull
| Hull type | Monohull fin keel with rudder on skeg | ||
| Construction | Fiberglass | ||
| Waterline length | 19.52 ft | ||
| Maximum draft | 3.94 ft | ||
| Displacement | 3858 lbs | ||
| Ballast | 1323 lbs | ||
| Hull speed | 5.92 knots |
Rigging
| Rigging | Masthead Sloop | ||
| Sail area (100%) | 217 sq.ft | ||
| Air draft | 0 ft | ?? | |
| Sail area fore | 115.46 sq.ft | ||
| Sail area main | 101.40 sq.ft | ||
| I | 25.60 ft | ||
| J | 9.02 ft | ||
| P | 23.23 ft | ||
| E | 8.73 ft |
Engine
| Nb engines | 1 | ||
| Total power | 0 HP | ||
| Fuel capacity | 0 gals |
Accommodations
| Water capacity | 0 gals | ||
| Headroom | 0 ft | ||
| Nb of cabins | 0 | ||
| Nb of berths | 0 | ||
| Nb heads | 0 |
Builder data
| Builder | Birka Marine (FIN) | ||
| Designer | Heinz-Jurgen Sass | ||
| First built | 1968 | ||
| Last built | 1975 | ||
| Number built | 200 |