I regard an 18 inch wave as big enough to avoid in my 15 foot fibrglass runabout (or my 12 foot timber dinghy, which handles it about as well if a bit more energetically.).<br /><br />I never want to be in either boat if there are 3 foot waves (although in the 15 footer I slammed off one bigger than that a few weeks back coming out of the creek blind into the bay and promptly turned around again when I got a safe space). <br /><br />Naturally it depends on more than just wave height e.g. wave frequency and wind.<br /><br />I go mostly in an area where strong swift tides running crossways against strong winds can cause a nasty chop with one foot white topped waves a couple of feet apart which are a lot worse than soft swelling waves yards apart yet twice the height in more agreeable conditions in another location.<br /><br />Or am I just a *****?<br /><br />Edit: It appears that my reference to a feline animal has triggered a row of asterisks. In Australia we don't censor references to p***y cats or derivatives, but it looks like meows-meows (or moggies as we call them) have a cultural significance which was lost on me when I posted originally, notwithstading the fact that I appreciate the various slang uses of the feline descriptor in the USA. So, for ***** as it appears above, just substitute "coward".