I got back and want to answer your note.

otnmbrd wrote:



Chuck Bollinger wrote:

The vertical clearance is measured from 'Mean High Water' in places
with a
single diurnal tide. In the Pacific Northwest, it is measured from
'Mean Higher
High Water' (MHHW).


Interesting ..... Can you show me where this information comes from? In
looking at CP 7, it list all heights as above MHW, unless otherwise
stated, and the only major change to this I can find is for the Columbia
River, which uses MLLW below Harrington Point, and "Columbia River
Datum", between there and Bonneville Dam.

And you are absolutely right. I cannot find anywhere that says that MHHW is
used in areas of semidiurnal tide. And yet, 4 out of 5 quite well educated
mariners swear up and down that they were told, or read, that information, but,
like me, cannot actually come up with the info.

That's great, and I appreciate your head check. Bull**** needs to be stomped,
no matter how well-intentioned.

I can't see why my tide program give me MHHW which isn't really very useful. To
use it risks being off by about a foot or so, in the wrong direction. But Mean
Tide and 1/2 the Mean Range isn't rocket science, so I'll continue in that
direction.

I see the conversation is raging away. Some pretty sharp people involved. I'll
take my discredited ass and go sit on the sidelines. {:-D