Unusual tides

Gents,

Can anyone tell me about the tides on the 3rd March, they were weird in that the tides up in the Pilbara were like one hour apart and no change in height, Derby had 6 changes in the tides during 24 hours, the last ones were only an hour apart and no signifigant change.

It's the first time I've noticed tides like these.

Cheers,
Dan.