Are you sure the cutless bearings in the hull are not worn? Speaking from experience there is considerable sag/ bending/droop over the length of those long shafts. That can give you incorrect alignment readings at the face of the coupling flanges. And if the front and middle bearings are worn, there’s potential for shaft “whip” under some conditions. If the 42 is the same as the 44, now is the time to replace all of them. That said, the OA yard in Seattle told me they sometimes skip the one by the stuffing box, but then they compensate for the sag at that end when doing the alignment. Not clear who’s doing the work, but checking with the OA yard might be worth the call.
That's a good point, and something we've discussed. The ones at the struts are in good condition from what we can see, as are the ones at the stuffing box. The ones in the strut are easy to remove with a press tool. The ones at the stuffing box are a pain in the ass, and many people do not replace them because of how difficult it is to get them out as long as they look good. I did talk to OA and that is one of the things they recommended, which sounds like they said the same thing to you!
Everything has been pointed out to you that could be wrong. You can follow your time frame and splash the boat before every vibration point can be addressed. BUT everyone here is advising against it. In 25 years, I've seen plenty of people delay a bottom job to accommodate their schedule, no danger of further damage. Just delay the haul lout until you have time to do it right. No boating over trawler speed until it's fixed properly. I have a feeling you have a boating trip planned and won't admit that's why you're in a time crunch. You know we'll all tell you to delay the trip. I Hope I'm wrong.
I don't have a boating trip planned - no hard dates or schedules that are forcing me back in the water. I live aboard my boat, so staying out longer is extremely costly - I think I may have mentioned that somewhere. Plus, there simply isn't room or time for them to accommodate me longer. The yard I'm at is booked out until September 20th, packed so full I have never seen it that way, and they just can't keep adding jobs on without having the boat physically sit for a very long time with no work until someone is available.
My day job is managing complex projects with constantly changing risk. In most situations with yards, I see owners drop a boat off and check in every few days, maybe less. In this situation, I'm 100% focused on the work that needs to be done out of the water, and help refocus them since I am there every day. Replacing the engine mounts is a great example. That needs to be done, but it does not have to be done out of the water. If we get the important things done out of the water, I can continue doing other things dockside or at a later date to improve things.
This thread got me to thinking about how to gauge if and whether there is an improvement based on the work done. I recently downloaded an app for measuring sound and have been using it as I work on soundproofing the engine room. I took Db readings at low and high rpm with engine hatch off, hatch on, rug covering, first improvement, etc. Changes are slight but verifiable.
Measuring vibration might also identify a plateau that we identify as a sweet spot in addition to having a vibration baseline.
Hey this is cool! Thanks for posting this. Some of my concerns about the vibrations I am sure are heightened because of the issues I've gone through, and very well may be no worse than it has been for 2 years! But instead of my subjective standing over the areas and moving around while underway, it would be awesome to be able to measure it. I'll have to look into this once I'm back in the water.
Thanks for pointing out my oversight/error/lack of thoroughness. I am glad to be wrong as to why.
I agree with your opinion about spending thousands on a barely detectable vibration. But it does seem the he wants to fix it, not sure about the money issue. But, if he's living aboard, it will still cost him more money if it needs to be hauled again. If the motor mounts get replaced later, in the water, won't he need to pull the boat to align the shafts? If that's true, maybe he should delay this haul until he addresses the motor mounts. Doing it in the proper order? Does this make sense to anyone besides me?
I definitely would like to fix the issue, but I am not willing to spend "anything" to do that. I look at each problem and review with the experts (which includes folks here, folks online, and the yard) what their best recommendations are for the particular problem or section, and weigh how much the work will potentially change the situation compared to the cost. I know some people who will spend anything and replace everything, regardless of the time or cost, and that is a great approach as well, if you can afford both the time and cost. In some ways you may be spending money to replace things or have work done with that approach when you didn't need to. I don't think I'm skipping any steps or areas that have been identified, or not looking at any specific areas - we're trying to make sure we track down everything possible to solve the issue, but of course, it is a boat, so some mysteries take longer to understand than others.
When you replace the motor mounts, you will need to do a new engine + shaft alignment, which has to be done in the water. The shape of the hull changes dramatically when it is out on the hard, and you cannot align it until the boat is back in the water and has settled for multiple days.
That's one of the reasons I've deferred that work for now - the other reason is the yard is so busy they don't have time to replace them right now. But they can do it in October dockside, without a haul out, and do another alignment then, which seems like a great way to get it done without sitting in the yard for 6-8 weeks.