Bruce, exactly my experience when I bought my old 189 M-15 down in Ridgecrest (desert near Edwards AFB). I was trailering over the pass (good highway) and the hitch came off at 55 mph. Chain held but left Some pucker marks on the drivers seat. The nut under the hitch boat side un-screwed. You are right, a cotter pin would have helped. I will make that mod this week. Larry Hughston Old 189 by Jerry M. -----Original Message----- From: montgomery_boats-bounces@mailman.xmission.com [mailto:montgomery_boats-bounces@mailman.xmission.com] On Behalf Of Bruce King Sent: Wednesday, April 11, 2012 8:13 AM To: montgomery_boats@mailman.xmission.com Subject: M_Boats: Towing safety reminder from my experience My crew and I had a bad experience while returning to Sacramento area from a Potter event in S.F. bay last year. Bottom line: Be sure you drill a hole in the threaded part of the trailer ball and insert a cotter pin blow the nut (or purchase this type). We ended up dragging my M15 and trailer by the safety chain at 60 MPH on I80 East due to a malfunction! The nut and a new lock washer came off despite tightening it with an 18" crescent wrench. It is a long story, but please, ALWAYS HAVE THE SAFETY OF A COTTER PIN UNDER THE NUT! PS: Don't tow Ericksons. And jerry, of course you're forgiven (funny, it could have happened to any of us) Bruce King M15 Fair Oaks,CA