Join Date: Dec 2014
Location: Montréal, QC
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Stern tube grease and propeller shaft
After having visited this forum many times since I bought my boat three years ago, I now feel myself obliged to post a first thread, hoping I will find great advises as it is so frequent here. I ask you to be indulgent for my English, because it is not my mother language.
So, here's my situation:
Last autumn, to give me the opportunity to make some maintenance work on the engine and the engine room, I pull out the engine from the boat and remove the entire propeller shaft, stuffing box and cutlass bearing system. I will change the stuffing box and the hose attached to the stern tube and also the cutlass bearing. I'm planning to put a Duramax Cutless bearing (the same that was previously there) and I don't know exactly which stuffing box I'm gonna choose.
As I was removing the propeller shaft, I was surprised to find that the entire stern tube was filled with grease. The owner from which I bought the boat, and all my friends at the boatyard never told me anything about the fact that there was grease in there and - so I'm concluding - it has to be refill periodically. Since three years I have the boat, I have never done that maintenance part (by ignorance), but everything seemed to work fine until now, and the propeller shaft shows no sign of wear.
However, as I am now aware of that fact, I start searching on the Internet for what kind of grease and what amount I will need to put back there when I'll be reinstalling the whole thing next spring. As I get more information, more confused I begin to be (as it is so often the case with sailboat). I've read that putting grease inside of stern tube was not recommended, because it will prevent sufficient water flow to reach the stuffing box and cooling it. I've read the comments of many people that seem to have the same type of installation as me and that were saying that a grease-free installation works fine. Others say that, because there was already grease there, it needs to have some, and that "a small amount" (without any further precision) would be sufficient.
I know that my boat is quite old, and that previous owners had done very amateurish work on it. I know that the engine has been replaced in 2002 by a Yanmar 2GM20, but I don't know if the propelling system has been replaced at the same time. I am wondering if the grease could have been put there in a previous setup, and been kept in place after having change some parts, not making it necessary anymore. I'm also wondering, in the case that greasing is necessary, if I need to clean all the old grease from the shaft and the tube before putting the new one, or if I could leave the old one in place.
What do you think about that and what will you recommend me to do?
Thanks in advance!