NavList:

Hi Mike

In 2015 we have published an article "Wave height and horizon dip" in the Journal of Institute of Navigation where we have investigated this problem in all details. Indeed, there are different misunderstandings and formulas with (+/-)(1/2)Hs or even factor (1/3) exist in the literature. The result depends whether you are on a big vessel or on a small yacht and whether or not  you take a specific moment.

You can find pdf of this article on the webpage of Siebren van der Werf:

https://sites.google.com/site/siebrenvanderwerf/file-cabinet/2015_Waves_and_dip_Nav.pdf?attredirects=0&d=1

A much shorter version of this article (where all math was put aside) was published in the Dutch maritime newspaper "Schuttevaer". Here is a link:

https://sites.google.com/site/siebrenvanderwerf/files-dutch/2015-Schuttevaer-05sept.pdf?attredirects=0&d=1

kind regards,

Igor