Test Question #2 C

You need to find if the high water or low water is spring or neap. In the Almanac if it is close to the red date then it is a spring tide. Close to a blue date then it is neap. You can also tell because the heights of the tide are higher at spring than neap. Once you determine spring or neap, then on the right side of the secondary port table use the appropriate MHWS or MHWN to get the height correction. In the example you are questioning on April 11 the Low water at 506 UT is a spring low water. Thus subtract 36 minutes. On the right side of the table Under MLWS the correction factor is 0.2m. Thus add it to the Port Frazer 0.5 m on that day to get 0.7m. Your mistakes seem to center around finding if it is neap or spring. January 29th and April 11th are spring. March 20 is in between.

I made the same mistake, and realized why: in the RYA almanac, the order of the columns is swapped from what is presented in this course materials. The RYA almanac displays the Low Water Spring times on the left, then the Neap times on the right, but then displays the MLWN on the left and MLWS on the right. So if you select the time difference and height difference from the same column (which is intuitive and matches the course materials), you end up with the wrong answer, since you are actually selecting the Spring time difference and the Neap height difference. Hope this helps!

I think Derek's comment helps. The MHWS MHWN MLWN MLWS are all labeled for secondary stations but the time differences are not labeled. Grant, can you confirm the order of time differences in the 4 columns in regards to springs and neaps since they aren't labeled and I don't see a legend anywhere. For the above mentioned problem, I assumed -0014 was a springs value. Thanks, David

The labels in the table are marked at the top of the column which carry down to the Rozelle cove differences.

Thanks Grant, finally found the table labels on the first page of Module 11. The depth offsets for MLWN and MLWS are flipped in the almanac but not in the module. Now everything makes sense!