The inscription 'Verwer' may have been inscribed over the artist's original signature. A comparable drawing was offered in these Rooms, 25 November 1992, lot 614. Two further such studies are in the Fondation Custodia, Institut Néerlandais, Paris (C. van Hasselt, M. van Berge-Gerbaud, Eloge de la Navigation Hollandaise au XVIIe Siècle, Paris, 1989, nos. 73-4, pls. 32-3). Dr. Hans-Ulrich Beck recently pointed out that the previously unidentified collector's number Lugt 2986b is that of Jacob Helmolt (1747-1808), a Haarlem collector, Der unbekannte Zeichnungssammler Lugt 2986b identifiziert: Jacob Helmolt in Haarlem, Oud Holland, 107, The Hague, 1993, no. 4, pp. 372-8.