The Battle of Slak (1631)

This is based on my translation of a section in Doeke Roos's book Twee Eeuwen Varen en Vechten 1550-1750:

A battle was fought on the Zeeland inland waters that received far less attention by historians than the Battle of the Downs (1639). This confrontation with the Spaniards was no less than an attempt to break the connection between the Rhine and the Scheldt and to separate Zeeland and Holland. The intention was to attack the two large forts on either side of the Volkerak. In this inland waters fight, on the night of 12 and 13 September 1631, both Johan and Cornelis Evertsen were involved. The Zeeland Vice-Admiral Marinus Hollaer ran into the ships. In the minutes of the Admiralty of Zeeland and the great roll in the Rekencamer, Johan Evertsen and the captains Clocq, Frans Jansen, and Andries Pietersen are named. Vice-Admiral Hollaer is not named, but he possibly had already been mentioned.

From the preceding, it is clear that he Republic was aware of the fleet preparations at Antwerp. The Spanish fleet consisted mainly of boats, defenses, pontoons, and launches, for a total of 90 vessels with 5,000 soldiers and boatsmen. A firefight took place at Saeftingen between the Zeeland ships and the Spaniards who wanted to enter the Mosselkreek. The many Dutch and Zeeland inland watercraft were smaller vessels with spritsail rigging. The deepwater ships, despite their draft, also had a chance to strike a blow, to saild and to divide the enemy in the fight.

Just as in the year 70 of the Sixteenth Century, success in Zeeland waters went to those with a good knowledge of the banks and channels and an acquaintance with the flow and tide. Among the list of booty lost by the Spaniards were many inland watercraft and cannons belonging to them. There were also four thousand prisoners taken. The Admiralty of Amsterdam wanted to dump these into the sea, but were prohibited by the Prince.

The result of the Battle of Slaak meant that the enemy would not be able to separate Holland and Zeeland. This was very important for the further course of the struggle against Spain and for the continued existence of the Republic.