Originally Posted by Melrna
...Right after I shot this video we lost the main steering. This is a story in itself...
6. Steering cable. When this happened I was very upset and still am. I know that after time the steering cable will stretch. But not after only 4 sails. I am blaming Catalina and the dealer for NOT adjusting the steering cables properly during commissioning. This put the crew and boat in danger. Remember. the Salty Dog rally, two Catalina's (38'&42') lost steering too. Not sure yet if this is a design defect out of Edson/Catalina or not properly maintain cable tension. I am voting for the later. So for the rest of you, if there is any slop in the wheel get your cables adjusted. You shouldn't be able to move the wheel right or left without the rudder moving...
I hope everyone can learn from this experience...
In the interest of helping others learn, I'll share my similar experience. My boat is much smaller, and the steering system is a smaller, simpler, lighter weight pull-pull cable system. So it's not exactly relevant to your design, but there may be some similar issues.
A couple years ago my chain jumped a sprocket in a relatively mild (15 kt) blow. The cable tension seemed fine, so I did some research. It turns out that my pull-pull system relies on an aluminum bracket to provide compression on the cable sheaths that must completely counteract the tension of the cables themselves. In a good blow, that aluminum bracket is known to flex a little bit, which can lower cable tension and cause the chain to jump. Tightening the cable tension does not fully fix this problem - the best fix is to stiffen the aluminum bracket. The problem was easily solved with an appropriately sized 1x3:
This past May I got caught in heavy following seas in the middle of the Delaware Bay. Not as bad as you had, but relative to my boat's size they were pretty big. (FWIW, I chose to run on jib alone to avoid an accidental gybe.) I had to use both hands to pull the wheel hard port after every swell/breaker, otherwise I would have broached. Every time I pulled that wheel, I said to myself, "I'm sure glad I reinforced my steering bracket." Otherwise, I am sure I would have lost my steering. Instead, the steering held up, without a single jumped sprocket.
Moral of the story: Increasing cable tension may not be the right answer for jumping sprockets. Check your steering design and see if there is flexing of the support components that could be solved by reinforcement.