Slight Vibration

[Maurice]

Hi Guys,

Since I've launched the boat this year I have a slight vibration that I can feel on the cockpit floor as I stand there under power. It is very slight, however, it is new. I know I didn't hit anything. I was motoring in the other day and heard a short squeek (sounded like metal on metal) then it (vibration) was gone for a bit...sort of wierd. The cutless bearing was fine upon launch as I checked it.

I run the engine in forward and feel it. In neutral it's gone. To be honest, I haven't even looked at it yet as I have been sorting out other engine problems for friends.

My plan:
-check engine mounting to ensure nothing loose.
-check coupling and bolts.
-will see if there is an obvious wobble in the shaft.

...any other ideas?

[smosher]

I would check the shaft and prop 1st for growth.

[Maurice]

I was dreading going in the water....but the Fleet Diving Unit in next door....have to call in a favor I guess. Good point.

[sastanley]

Mo..i hear ya..the diving under the boat thing is not on my favorites list.

I have a buddy that will usually do it for me when we raft up together..he often carries his dive gear! :cool:

[Dave Neptune]

Mo, I had a similar instance but without the squeek. I had a vibration that I started feeling through the cockpit sole. It started out a bit intermitant then started getting worse as the 5 hour trip to Catalina continued. When I arrived at the island I went over the side to check and found nada. So I began getting ready for a stay of a few days. While getting out my flopper-stopper I noticed a tie strap holding my exhaust hose had broken and the hose was touching the corner of the cockpit. So I doubled the strap when replacing it and no more vibration on the way home~~it was simple and basic.
Be sure and check for something loose. I didn't really think that the hose was the problem, until it was confirmed when I left.
Could be a fishing line with a weight and/or a sinker, I've had a few of those over the years.

Dave Neptune:cool:

[Maurice]

Thanks guys.

I double checked it all yesterday, was in the water and no debris and anode in place. The squeak I had mentioned only happened once and lasted about a second.

Right now I don't feel anything abnormal at slow speed, however, just a very fine one at full throttle...that might be normal wear on the cutless. Not entirely sure about that, however, the vibration is nowhere near as bad as I had experienced earlier. It very well may have been a piece of rope or something on the prop and it may have released and come off...perhaps that's when I heard the squeak.

Regardless, I honestly think I have a small vibration at 6kts that I don't think was there last fall. The other thing that crossed my mind is if someone or something bumped my prop in the yard, or I could have had the spinning prop hit something and I didn't notice... I'll live with it for now and if it gets worse I'll pull it for a look-see. Thanks to all for your input.

[Maurice]

I think my vibration is valve related. Today noticed it again under load. I am suspicious of number 3 cylinder. Plug burning nicely and fire. I have the electric fuel pump located on the bulkhead next to the valve side cover and I think I have a very similar noise there too. Will take down a stethescope (God knows I have lots of them) and check it out for sure. I am thinking broken spring perhaps....will see on the 4th.

This engine has run so nice for 4 years and it's no shame for it to need a bit of TLC. If worse comes to worse my spare engine might be sitting in there in 24 hours (although I don't think it will be necessary).

[Maurice]

Went through it all today. Plugs, wires, ignition.......all good. Had stethescope on the engine, listened up down and all around that engine....not an abnormal sound to be heard in any range. Compression good all four cyl...115-120 range...not bad at all. That was surprising as I thought that fuel pump was masking a valve noise or something.

With the boat tied to the dock I had a friend put it in forward as I watched for change. I can see the engine try to move on her solid wood rails. Mounts bolts are good / tight, shaft on inside of boat is short but no sign of wobble there. Also played with the timing under load and it ended up back where I had it as there was no problem with that.

I do notice a bit of a different exhaust sound as this happens also..not sure if it's because I am listening so closely trying to locate the cause of the vibration or perhaps it was always like that. In the next day or so I am going to pull a section of the exhaust hose to have a look at that.

I have decent forward power but she will hit 6 kts only in calm weather...usually could hold 5.7 in a decent blow now it's about 5. I had someone dive and see if there was anything on the shaft last week and there was nothing.

If there is no restriction in the hose (hot section new last Sept) I will have to haul the boat for a look at the prop and shaft. Anyone else ever deal with this.

[msmith10]

Mo,
My C&C 30-1 has an aluminum L-channel which attaches across a couple of small stringers on each side of the packing gland for the stuffing box. This channel has a cutout which surrounds the body of the packing gland, thus fixing the position of the packing gland and packing nut as well as keeping it from turning and preventing any torquing forces on the rubber tube of the stuffing box. If my engine/shaft gets a little out of alignment, the packing gland will knock on the aluminum channel which then gets transmitted to the stringers and it feels like the whole cockpit of the boat is going to shake to pieces. It is hard to see how much out of alignment the shaft is until you remove the aluminum channel because it fixes the stuffing box in position somewhat. When you remove the channel it is much more noticeable. At the same time, the vibration diminishes because it isn't transmitted to the hull.

[Maurice]

Thanks Mark. I will have a look at that as soon as I get a chance.

[Maurice]

Checked everything I can think of....even went into the water myself today (COLD). Normal cutless play, anode in place, no debris. I can't find the source. Not going to worry too much about it. If it gets worse I will haul her and deal with it on the hard.

Late Entry: No need for engine:) Took the 10 year old twins for a sail in 17 kts yesterday. 35 footer tried to race us...imagine that. They crossed my bow and the 4 of them look my way with that "you want to go" look. I thumbed-up Thrumcap and it was on. By the time we were set after the tack they had 500 ft on us. We travelled a mile holding our own but I needed heavier air. We tacked to the west as they continued close hauled for the bouy 4 miles away...( I knew they would have to pinch to make the bouy). We tacked over 1/4 mile to the west getting lifts from the land and then turned for the bouy on a close reach. Odyssey held 6.8 to 7.2 for almost and hour and we rounded the bouy about 1/4 mile ahead of them. On the way back in my 10 year old son Eric with a grin puts three TV dinners in the oven as she makes about 5.7 to 6.5 kts all the way home. First time I actually raced with the kids aboard ... they got into it ... it's a good thing they didn't have guns as they were a bit nervous as he pulled away when we tacked ....good experience for them. Boat is running fine, engine used only to bring her alongside...as it should be.

[Maurice]

Found the vibration problem today. Although the vibration was slight, I was like a dash rattle in a car to me.....had to be found...had to be fixed and I'd rip the boat apart if I had to...regardless.

I pulled the boat 9:30 this morning and found the anode had deteriorated unevenly, leaving it out of balance and affecting my shaft balance. One look at it and I knew I had the culprit. I had another 7/8 anode in the garage and put it on with some lock tight on the threads...I always do this so they don't loosen.

While I had Odyssey out I shined her topsides with Poly-Glow; cleaned a few spots on the keel that were the paint was blistering, epoxy then new bottom paint on that....put her back in the water 8 pm tonight. I'll attach a few pics but forgot to take one of the anode as I had done that fix immediately.

Once I put the boat back in the vibration was GONE!

[jpian0923]

Nice account of the race too. Thanks for that! :D

[msmith10]

Very nice photos, Mo.
I wish my topsides looked like that. They probably did 30 years ago.
The C&C 30 is just a blast upwind in 15+ knots. That's when I win a lot of races.

[Maurice]

Mike, the stuff is called Poliglow. It's a product that was developed for fiberglass / gelcoat / painted surfaces. The first pic with my truck in front is what she looked like after 2500 nautical miles since last application. I like the stuff, but I have heard others say they don't like it.

Mine had worn off on the bow, but I did punch 2500 nautical miles since last application. The only ones that I know, that don't think it's the best, are the cockpit warriors tied to the dock and don't sail their boats.:eek:

Email me at home mmullaley@gmail.com if you'd like more info. It's good stuff and easy to work with. I had the boat cleaned and done in about 4 hours...no time for beer because you have to keep moving or it gets screwed up.

The first pic is what she looked like when I got her. The second is as she looks today. I "wet sanded" the hull with 1000 grit sandpaper in 2007 and it looked very dull when I was finished (the pic is what she looked like with all the oxidation etc...the sanding removes all of that). Then the poliglow and it looks as good as a new paint job after the 3rd coat. Supposed to apply 1 coat yearly but sometimes I go a little longer and it still looks good.

http://www.poliglow-int.com/