Beitass

A beitass, or a stretching pole, is a wooden spar used on Viking ships that was fitted into a pocket at the lower corner of the sail. This innovation was used to stiffen and hold the edge of the sail when sailing close to the wind.^{[1] [2] [3][4] [5]}

References

1. ↑ "Ship construction Topics". 
2. ↑ "Glossary of Viking Words". 
3. ↑ Grambs, David (1993). Did I Say Something Wrong?. Penguin Group. p. 75. ISBN 0-452-26831-1. 
4. ↑ Gedney, Elias. Ships and Navigation of the SCA Period. East Kingdom Guild of St Erasmus. p. 11. 
5. ↑ Culver, Henry B (1992). The Book of Old Ships: from Egyptian Galleys to Clipper Ships. Dover Publications. ISBN 0-486-27332-6.