Cabin vibrations...

S

South of Heaven

New member
Are there any tips on how to reduce the cabin vibrations while underway? Obviously at headway speeds they're almost non-existent then at a good clip they can be quite annoying (at least on my boat).

Maybe a better question is where are the vibrations coming from? Is it from the added accessories and loose gear? Or is it the v berth partition and the windows?

I'm not looking for a miracle cure..... but if I could reduce some of vibes I'd be happy. Just to be clear; the noise(s) I'm hearing have nothing to do with the engine or rigging.
 
Depending on your trim angle the noise can be water slapping the bottom of the hull at about the head of the berth. In my 22 you can hear this coming from the flat area just aft of where the porta-potti stores. Unless the water is completely flat there will be some noise from this area. You can hear the change in the sound as the trim changes. Bringing the bow down some can help. IMO its just one of those C-Dory things.
 
I get some annoying vibrations from the panels in front of the motor well and fuel tanks. I'm thinking of taking them off and putting a rubber washer between the panels and the lip of the motor well. Maybe putting another screw/washer/bolt farther out towards the gunnels where there isn't any fastener now.

Getting to the back of that section presents some challenges tho......
 
So many different things that could be making the rattles, it would be hard to guess where to start. I mean we all have different things in our cabins as well. An example of a rattle/vibration I have that might be similar to others, is the KISS stove top. I dampen that down by keeping a towel across the top of it.
 
South of Heaven":1peqagyj said:
... cabin vibrations while underway? Just to be clear; the noise(s) I'm hearing have nothing to do with the engine or rigging.
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It almost seems like they would have to have something to do with the engine vibrating things on the boat when underway (?) There is probably also a certain resonance of the hull but that would still be related to the engine, I'd think.
 
Assuming your prop(s) are well balanced and free of seaweed, have crew move about the boat and begin touching cabinets, gear, or anywhere it appears the vibrations originate. If someone notices a difference in noise or feels a vibration in specific locations, do a close inspection of that area when dockside.
 
Sunbeam":8nsixy6o said:
South of Heaven":8nsixy6o said:
... cabin vibrations while underway? Just to be clear; the noise(s) I'm hearing have nothing to do with the engine or rigging.
Click to expand...

It almost seems like they would have to have something to do with the engine vibrating things on the boat when underway (?) There is probably also a certain resonance of the hull but that would still be related to the engine, I'd think.
Click to expand...

I agree with Sunbeam, Vibrations are most likely from engine and in particular something off balance --> most likely that would be prop generated. Check there first, any notches, or paint missing, it might be worth having a prop shop check the trim and balance.

Other noises, (rattles), are things rubbing or shaking together. Loose hinges, drawers not tight, dishes rattling on the shelf. These sounds should be easy to separate from water splashing on the hull. And if it's water splashing on the hull and you don't like that sound there are 2 cures. One, slow down, at 5 knots or less, there won't even be a bow wave to hear. And the other, (sorry about this one) I guess would be to keep the boat on the trailer in the driveway.

I understand the irritation of the sound of the change rattling in the ashtray, but I like the sound of the water on the hull. It does disturb me a bit when I hear the sound of the waves going over the windshield :shock:

Harvey
SleepyC :moon

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At certain speeds we get vibrations in the door and windows quite annoying Changing speed sometimes helps . The glass door vibrates on it's rubber stopper ? Play the music louder or slow down? Good Luck and let us know what was giving you Bad Vibrations
 
I was surprised at the amount of noise and vibration when I went for my first cruise. I admit that I wasn't all that familiar with planing fiberglass hulls. My previous experience was a kidney pounding day in a ski boat from one beer-selling marina to the next. Still, I was a little disappointed that the CD 16 not only pounded, but that the hull and cabin seemed to amplify the slap, bang and vibration. I don't know how much of this will apply to other C Dorys, but here are some of the things that I have done to make a few hours planing more enjoyable.

My basic idea was to reduce, where I could, the "open panel" areas on the boat. Even thought the chines on the hull stiffen the hull and reduce it's ability to act as a drum, I still wanted to tame those areas if I could. For instance, where the V-berth meets the hull in the 16, it is simply glassed with no fillet. I climbed in there with a spray foam can and added about a 4" foam fillet on the underside. It doesn't really stiffen anything, but it does deaden the hull noise at the bow. I also ran my thick rubber cockpit mats well forward under the V-berth to deaden the hull slapping.

When I removed the cockpit side panels, I exposed large pieces of EPS that were simply stacked behind the panels. When replacing them, I tacked them in place with spray foam, as well as tacking the EPS to the outer panels. This also removed a lot of the "oil canning" effect of the solid hull and panels to transmit noise. The boat began to feel solid, instead of a thin skin of fiberglass slapping across the top of the water.

The V-berth and cabin also got a coat of rubberized "sound proof" paint, shown in my photo album. I haven't had any problems with condensation, despite spending a few nights with the temps in the low 40's. But I sleep with plenty of ventilation, so that helps. As to sound reduction, a thick layer on the sides of the V-berth, as well as the entire cabin, really helped eliminate the "tin can" sound. Noises vibrating through the hull into the solid fiberglass cabin gave planing speeds kind a frantic feeling, in my mind. Cutting down on the wham, bam, and vibration made cruising at speed much more comfortable.

On my last cruise, I took along my noise cancelling headphones. They worked fine and removed a lot of engine sound. I'm sure that they would eliminate a lot of vibration sound. But after a few hours they aren't comfortable, so I used them less than I thought I would. It could also be that I'm getting more used to the remaining noise and vibration on a planing hull. It could also be that the level of noise and vibration in a 16 is such that I can't even hear the little things that bother those on a larger C Dory. I once had a Jaguar that had an irritating rattle of the ignition keys on the dashboard. Then I realized that it was the first car I'd ever had where I could possibly hear that. So unacceptable noise and vibration is relative.

Mark
 
Goo luck. I don't think my 22 is terrible, but they are loud and that's because there is no sound insulation anywhere. As some noted, they seem to be accentuated due to the cabin. I'm sure there is stuff one can do to help, but I wouldn't expect much.
 
The table in my 22 rattled quiet loudly in the brackets. I solved this by putting small O-rings on the shaft that connects the two halves of each bracket.

One thing about the design of the C-Dory is that the cabin floor is inside surface of the hull (like a Jon boat). The sound of the boat through the water is radiated right into the cabin. Most deeper V bottom boats have an inside floor and a gap between the floor and the hull. The gap itself can deaden the sound (or amplify it). Filling this gap will foam will do a lot to make a boat quieter.

I have also noticed that at cruising speed on my boat the sound of the engine seems loudest at the front of the main cabin (e.g. helm position), moving to other parts of the boat are quieter. In fact being in the cockpit is quieter than the helm position even though you are much closer to the engine.
 
Take a good look at the cabin side panel screw blocks that are glued to the underside of the deck. I found a few blocks had Brocken their bond with the deck & did some annoying vibrating against the underside of the deck at certain speeds. This was mentioned years ago by another 19' brat & solved my cabin vibration/noise problem.
 
I don't think you can deaden the noise, from every source, enough to not do harm to your ears. Rule is, if you can't understand some one, 3 feet away, talking in a normal voice, you need ear protection. We use ear plugs, before we go on plane. They're handy to have around in those noisy marinas, and we even used them on Lake Powell when the houseboat down the bank decided to treat us to a rap concert at 1100 at night.
 
I don't like noise, so I, too, wear ear protection when underway, even though it's a bit of a pain (bugs my ears). So far that is either just foam earplugs, or my workshop earmuffs. I've been considering some Bose noise-cancelling products, but as of yet haven't decided between the headphone or in-ear ones (they are too expensive to just buy both to try, but I don't have any way to try them out, so I've been procrastinating). From reading reviews, etc. it seems that the Bose are the best in terms of noise-cancelling (you can wear them for that without listening to music, if you want to).

(This is just because of the overall sound level, not one or two specific things rattling around.)

Anyone use either (or both) of the Bose styles? (I think maybe ghone does?)
 
There are some folks that would agree, My hearing is not the best. Might have to do with to much air time in helicopters or something. Here are some observations on noise and hearing. NOTE: none of these are scientifically substantiated.

Hearing is a sense that provides protection 360 degrees around me, so I don't wear headphones, or ear buds when driving my car, riding my motorcycle (which is about a 5 on a scale of 1-10 in loud) or running the boat, or for that matter, in my house. I can hear where I can't see, like behind me or in the next room. I do try to keep the volume(s) down, but my ears aren't getting any younger.

In comparison, my sailboats, when running downwind were quiet, (about a 1 or 2 of 10) boating on a beam reach things went up to a 3 or 4, maybe a 5 occasionally). My friend's Thunderjet 22, (an Aluminum, strictly fishing boat), with a huge I/O, jet drive, no carpet and metal seats rates about 50 on a 1-10 scale of loud.

In my C-Dory, much of my cruising is below 6 knots, and even with the cabin door open it is easy to have a conversation at living room volume levels. When cruising at fast planing, 15-18 knots, and the door closed it is still possible to have a conversation without yelling.

Yup, there are things we can do to make our boats quieter, and some have gone a long ways in getting to living room sound levels, but it seems to me that there should be some realistic expectations along with taking reasonable care to ensure the dishpan in the sink has a towel wrapped around it.

If I am crossing the Strait, and there is water sloshing in the cabinet space under the sink, I want to hear the change in the sound the boat is making before I feel the water running in over the top of my shoe. (Admittedly, that is a pretty extreme example so YMMV.)

Harvey
SleepyC :moon

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We have the older style C Dory with the "Wooden" or decra guard door. We had a lot of noise underway and traced it to loose screws on the door hinges which allowed the door to rattle and vibrate creating quite a racket. A drop of reversible loctite and tightening the screws made a world of difference.
 
I can see where might want to retain all of the "noise" if your hearing is reduced. In my case, my hearing is pretty good, so with my earplugs or muffs on, I can still hear those "little signs" of engine changing pitch, stuff outside, others on my boat, etc. So for me it's mostly just taking off the "bad" noise (and preserving my hearing so I can still hear those little whispers of the anchor rode or etc. when not at anchor, which is also important to me). I also feel less fatigued (fatigue leading to poorer judgement) if I haven't been harangued with noise all day. But as you say, these things may not apply if you already have a fair bit of hearing loss.
 
Here is how it works on our boat.

I hear any rattle like sound, I ask Cindie to find it and fix it OR drive while I find and fix it.

Our boat is pretty quiet as rattles go because I can't stand them. Cindie doesn't mind so much.

Greg
 
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