tag:blogger.com,1999:blog-903444638046674243.post4076406786997727911..comments2023-10-23T19:46:33.401+01:00Comments on nb Lucky Duck: Day Twenty-Seven-Why didn't we buy a boat with a bigger engine room?Amyhttp://www.blogger.com/profile/13190832458135017656noreply@blogger.comBlogger4125tag:blogger.com,1999:blog-903444638046674243.post-23795339070125452732008-08-29T18:50:00.000+01:002008-08-29T18:50:00.000+01:00Moominpapa I think you are right. The piece of st...Moominpapa I think you are right. The piece of steel is a machined collar which fits into the stern greaser and fits tight up against the back of the flange of the Centraflex coupling, but was obviously an addition (The Centa catalogue doesn't show any such bearings). The collar wasn't fixed to the shaft. The main problem James and Amy are facing, is that the prop shaft is worn, and the cone shaped flange of the Centraflex coupling cannot be tightened enough to grip the shaft. The grub screws are in some holes which have been drilled through the flange of the coupling perpendicular to the shaft. There is a hole for one of the grub screws to locate in, and there are two small dimples for the other grub screws. This just about works when going forward, as the prop pushes the shaft into the coupling, but when in reverse, the prop is pulling the shaft out and loosening/shearing the grub screws. Basically it is a bodge! The only real fix is a new shaft and flange for the Centraflex. James' Dad.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-903444638046674243.post-85329799283591851432008-08-29T08:35:00.000+01:002008-08-29T08:35:00.000+01:00The more I think about it, the more I'm convinced ...The more I think about it, the more I'm convinced that your "oil seal" is a thrust bearing. Why would there be an oil seal there, except to keep lubrication in a bearing? If it has a bush which was welded, that could be how is was attached to the coupling/shaft, and the root of your problem is that it's no longer attached.<BR/><BR/>The axial forces from the prop will be much larger than the rotational forces from the engine. (It's roughly the same power in each case: power is force-times-speed: how much faster is the shaft rotating than the boat moving: that's the ratio of rotational to axial forces.) Plus axial load on the coupling will distort it and mis-align everything.<BR/><BR/>If I'm right, the key to solving the problem is re-attaching the bearing to the shaft. Carrying on as you are is doomed to fail, and risks totally wrecking the coupling from out-of-spec axial thrust.<BR/><BR/>Email or phone me if you need to (Jim and Sarah have my cellphone number.)<BR/><BR/>MP.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-903444638046674243.post-71381961976701423222008-08-28T22:55:00.000+01:002008-08-28T22:55:00.000+01:00This has been a bit of a baptism by fire hasn't it...This has been a bit of a baptism by fire hasn't it? Well done to both of you for keeping so positive - you will laugh at it further down the line of course but for now it must seem a bloody nuisance. Best Wishes<BR/>Nb CaxtonNb Yarwoodhttps://www.blogger.com/profile/14806115768980012184noreply@blogger.comtag:blogger.com,1999:blog-903444638046674243.post-2066393799590988712008-08-28T22:36:00.000+01:002008-08-28T22:36:00.000+01:00Hats off to you both each time a problem emerges y...Hats off to you both each time a problem emerges you seem to rise to the occasion and put it right.Anonymousnoreply@blogger.com