savvy navvy? https://de.savvy-navvy.com/motorboat-navigation-app?gclid=EAIaIQobChMIvty0wYy6-AIVD-R3Ch18CQUIEAMYASAAEgIWevD_BwE
Noch zwei weitere Alternativen... Der Altgediente: https://seaiq.com Der Newcomer: https://navstation.net