Ketch mizzen sheet. So on a ketch, the dual purpose of the mizzen sail is to both propel and balance the vessel, while on a yawl, the smaller mizzen mainly serves the purpose of trim or balance. Yawls tend to have mainsails almost as large as those of comparable sloops. A ketch may be distinguished from a cutter or a sloop by virtue of having two masts rather than one, though a ketch with two foresails is sometimes called a "cutter-rigged ketch". Both the ketch and the yawl differ from the two-masted schooner, whose aft mainmast is taller than the foremast.
Norda steel keel is added under the wooden keel, to provide more counterweight in order to add higher masts and more sail. Its sail plan is wishbone ketch. Norda Norda is a wooden sailing vessel that was commissioned in 1928, originally used as a research vessel in Poland. It served as research vessel, fishing vessel and is now a yacht. The vessel was commissioned in 1928 by MIR (Polish Fishing Institute). It was built in 1928 to order of in the Andersen Shipyard in Frederikssunde, Denmark. It was christened "Ewa", inspired by the names of daughters of both Professor Michał Siedlecki