Originally Posted by NoTies
Please tell me they meant to say bronze nut, not brass.
Sorry! I meant Bronze!
You are quite right about getting the best information from a marine engineer
. I am sailing as first assistant engineer
now and will upgrade to chief unlimited in March when I complete my next 90 day rotation on a heavy lift
ship with a huge flexible coupling about 6 feet in diameter! I know that every ship that I have worked on has had more than one bearing on the shaft and I understand what you are saying about shaft whip and I have decided to eliminate the flex coupling on my boat but I will look into another type of rigid coupling that has a sacrificial part that will break if there is something that hits the propeller
. In this case I would care a spare part so that I could get underway again after replacing the part. I may in the end go for a direct coupling from the shaft to the gear
box. I guess I didn't think things out very well when I blindly followed Beta Marine's opinion about that Centaflex coupling. The main reason that I took that coupling was because I needed to fit my shaft on a Beta instead of a Volvo gear
box and this seemed to be a quick and easy solution to solve this problem. I think that if there were two bearings on each end, which must be rare in a sailboat, that I would still go for the Centaflex coupling. I will also contact Beta Marine
and try to educate them a bit better about the shaft whip that I did experience on my my boat. It was Beta Marine
that was pushing the idea of the Centaflex coupling as an option on their new engine
and gearbox installation
. However it may be a good idea to get that rigid coupling that will break if I hit something hard enough to protect the gear box from damage just like a shear pin on an outboard motor
. What is your opinion on that?