No water under the keel
In order to give the children in the Netherlands a special joy, St. Nicholas distributes his gifts there on 5 December. For this he travels from Spain by ship. On his journey, St. Nicholas is accompanied by his magical horse and the captain Wichtel Bonny. The three are always eagerly awaited and solemnly welcomed in the harbor.

So that the children of all port cities can greet St. Nicholas, he chooses a different port for his arrival every year. This time he chose the port in Delfzijl. The crossing from Spain to the Netherlands runs smoothly so far. But shortly before arriving in Delfzijl, the ship slows down and suddenly stops.

St. Nicholas rushes to Bonny on the bridge: "What happened? Do we have a leak?" Bonny reassures St. Nicholas: "No, no. There is no leak. We're just having low tide. The water level in the port is too low to enter. We have to wait for the flood again." St. Nicholas breathes a sigh of relief: "Oh yes, the tide!". But then he gets hectic again: "But the children are already waiting for us! We wanted to be in the port by 6 p.m. at the latest.Now it's already 5:30 pm! How long are we stuck here?"

Bonny explains: "The average water level in the harbour is 2 metres. With the weight of the many gifts, we have a draft of 2.50 m. We can only continue when we have at least 50 cm of water under the keel in the port of Delfzijl. On the tidal diagram you can see when the water level in the port is sufficient again (see picture)."


At what time can the ship enter the port of Delfzijl at the earliest?

[Note: Draught means how deep the ship dives into the water. The keel lies at the deepest point of the ship's hull.]

a) 9 pm
 b) 10 p.m.
 c) 11 p.m.
 d) At midnight

 Dec 5, 2021

See diagram below:   You need 3 m of depth ( 2.5 m  +  .5 meters ) 

       Yellow line is tide at 2.5 m      Blue line is 5:30 PM      (Intersection is their situation presently)

       Green line is depth 3.0 m       Black line is 10 PM (when the tide causes depth to next be at 3.0 m)


 Dec 5, 2021

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