| # | Country | Total Patents | |
|---|---|---|---|
| #1 | Sweden | 3 | |
| #2 | Italy | 2 | |
| #3 | Netherlands | 2 | |
| #4 | Australia | 1 | |
| #5 | Germany | 1 | |
| #6 | Denmark | 1 | |
| #7 | United Kingdom | 1 | |
| #8 | United States | 1 |
| # | Industry | |
|---|---|---|
| #1 | Transport |
| # | Technology | |
|---|---|---|
| #1 | Marine propulsion |
| # | Name | Total Patents |
|---|---|---|
| #1 | Astrand S I | 4 |
| #2 | Astrand Sven Ingvar | 4 |
| Publication | Filing date | Title |
|---|---|---|
| NL8004905A | Apparatus installed at a boat screw. | |
| US4086025A | Propellers with retractable blades |