Greetings … I am having some unnerving vibrations on my Nonsunch 30U. They can generally be eliminated by changing engine RPM. But still don’t like that they are present.
Unsure whether it is due to feathering prop, alighnment or transmission issue. Was hoping to have someone look at it while out on Eastern Long Island.
I am actually in the vicinity of the rendezvous in Southampton (in transit). And I hope to come for the day tomorrow.
Any recommendations on someone to look at the issue in this neck of the woods?
I’m no expert, but I have had some experiences with vibration that might be helpful to you.
First, when I was sea trialing the boat before purchasing it, there was a terrible vibration when the boat was in gear, but little to no vibration when it was out of gear. It was so bad that the top of the stainless hand rail on the binnacle moved a few inches fore/aft when the engine revs were increased. The mechanic said that the engine was in very good condition and had nothing to do with the vibrations and agreed with the rest of us that it was drivetrain related. So I skipped on the WOT part of the engine tests and went on to haul-out.
Yup. The boat had a two-bladed folding prop and it was totally shot. So much that the tips of the blades could wobble 1/2" or more. That had also ruined the cutlass bearing. I had both the bearing and the prop replaced (Gori 3-blade, 18") but did not get the opportunity to drive the boat until it was in San Diego. (I had it trucked here due to weather.) Fortunately, that fixed the problem and the terrible vibrations were gone.
This is an easy one to test for: rev the engine up and down a few times while in neutral and see what happens. If it’s drive train, it should not vibrate in neutral and the vibrations will probably become worse and worse as you raise the RPMs while in gear.
Second, over the first few years of my ownership, and beginning on day one, I noticed vibrations at certain RPMs. Not terrible ones, but enough to make the teak deck grating rattle and the cabin door if the two halves were partially touching. I attributed it to having a 3-cylinder engine because I’d never had one before and it made some sort of weird sense. Then this spring I had three “sails” where the winds were awful or died completely. I had been using the engine just to get me in and out of the marina, but now I ran it much longer on a few occasions and once I ran it pretty hard for a few hours. After that last day of hot, hard running I was heading back into the marina and I noticed that I did not have to search for a quiet RPM. Any RPM was smooth and quiet. I, and the PO, had apparently been allowing the carbon to build up and the engine did not like that. This is a well known problem with diesels and I knew about it, but it was inconvenient to actually act upon it on my own engine. Now I give her a longer, harder run every now and then to keep the engine healthy and running well.
It kind of sounds like you might be experiencing the second symptom that I described, but I’m sure there are plenty of other explanations, too. It’s not overly expensive to test out, thought it takes a few hours of running at higher RPMs than you might be used to. In my case I did not just hold it at constant high RPMs. I was running faster for a while and then slowing to a more conventional cruise speed and then running faster, etc. Keep an eye on the temperature gauge if you try this and keep your ears open for something that doesn’t sound right.
Another possibility to consider is bad fuel. In fact, part of the reason I decided to run the engine so much rather than just give it up on those really slow days was that the fuel in my tank is getting pretty old and I wanted to use it up. I use stabilizer in it and have good filtration which I change annually and check frequently. But still, a 40 gallon (I think!) tank from which I use about 7 gallons a year (going in and out of the marina) was concerning. Much of the fuel in my tank is probably still from the PO and the boat was for sale for quite a while so I have no idea how old it is. Maybe from the time of the dinosaurs for all I know. So, while my engine now runs much smoother than before, it might totally purr if I fed it better fuel.
You can try Safe Harbor Marina in Greenport. Ask for James, the service manager. (631)477-9594. They’ve been keeping my Nonsuch 26 in good shape for the past 10 years.
This Tuesday while motor sailing in Vineyard Sound about 1/2 mile off the north shore of Martha’s Vineyard I had an interesting adventure. I first noticed a sudden lack of propulsion and then found about 3" of water in the cabin. I didn’t know where it came from or how bad it was so I headed for the beach where I ran the boat aground in soft sand (better to sink in 2’ of water than 50). It also occurred to me to drop the anchor. The boat had about 50 hours on a new Yanmar engine and transmission that had been installed this past winter. Prior to the mishap I felt no unusual vibration and considered the Yanmar an improvement over the Westerbeke it replaced. The cause turned out to be a misaligned shaft which broke loose from the transmission coupling and started to slide backwards through the stuffing box and out the hole in the hull that the shaft passes through. Much appreciation for TowBoat US which came promptly, pumped out the water, plugged the leak and towed me to MV Shipyard. (The operator of TowBoatUS later told me that dropping the anchor was smart to prevent anyone from claiming to salvage the boat). Cudos to MV Shipyard which had a crew standing a 9PM to get the boat out of the water. Thanks also to the Coast Guard, Menemsha Station which dispatched a boat to stand by and took the other 3 souls onboard ashore. Much appreciation too for the Shipyard for the courteous and professional way they’ve handed the situation and for taking responsibility for the repairs. Shit happens with boats (first time in 41 years of sailing for me) and it’s good to have good people do their jobs the right way.
I consulted my new best friend Claude about rebuilding the drive train. For what it’s worth I’m attaching a word document with specifications that Claude provided. Claude did not include a shaft retention collar - which the Shipyard is already in the process of ordering. I put my faith in the Shipyard over Claude just as I trust my doctor’s medical advice over something I googled.
I would appreciate recommendations from NS 26 owners based on experience with the drivetrain components in their boats.