Dashboard Popping Noise - 340 Dancer

Just a Splash

New Member
Oct 16, 2007
9
New Bern, NC
RE: 2000 Sundancer 340 - 140 hours

We just took our new-to-us 2000 Sundancer 340 from Oriental, NC to Ocracoke, NC on the outer banks (our most ambitious trip to date). We were running about 10-15 kts in 3 ft seas and the boat was making a god-awful noise as it banged into each wave. Basically from the upper dashboard area, port side, forward of the cockpit sink and just a few inches aft of the windshield base, there was a loud "CRACK" noise each time the boat hit a wave. Keep in mind that this was not an otherwise uncomfortable trip so I don't think we were asking too much of the boat. But the noise was driving us all crazy, CRACK-CRACK-CRACK every other second!
I think the noise is emanating from something under the dashboard in that area, perhaps the interface with the forward wall of the lavatory underneath or some sort of bulkhead in that area. We tried putting pressure on the windshield, the companionway door and the top of the dash, but to no avail, the noise seems to be coming from two structural members rubbing together (like fiberglass on fiberglass) somewhere underneath the dash panel. Interestingly, the noise was much quieter from inside the cabin.

Before I ask my mechanic to take apart half the boat to find it, has anyone experienced this before? Any ideas on where to start?

Thanks for your responses, this forum is a great resource!
 
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For what its worth, I have that same noise on my 260 Sundancer. You could not have described it better, it is quite a noise. it sounds like the boat is splitting in two. My sound comes from the windsheild area under the dash board.

I've narowed it down to one of two things, under the dash there are a couple of alarm horns that are smaller than a golf ball, and they are just hanging there on wires. I think when under way they start to swing back and forth, and when you hit a wave they swing up and wack up against the fibre glass dash making a loud crack sound.

Or, it could be the sound of the whole dash board itself as it flexes and hits fibre glass that is it is mounted too? I've been told that there is some flexing going on when you do hit decent sized waves, and not to worry, its just the sounds of boating.

I talked to my sales person at Sea Ray and he said it is normal. I will pay attention to this post to see if there is anything I should be worried about.
 
Any chance that the seat in the head is bouncing up and down?

How about your microwave? Ours has a glass platter in it that rotates. I have to pack towels in it when we travel to keep it from making a terrible racket.

Michael
 
Ski Bum- Nope it's not the toilet seat, I was sitting on it while trying to diagnose the noise! Also not the microwave plate, that is too far forward. It sounds more like something directly underneath the dashboard rubbing against the underside. More like the fiberglass on fiberglass noise that Reefer described. When you put your hand on the horizontal surface of the dashboard immediately aft of the windshield you can feel the popping.

Hopefully somebody out there has successfully fixed this same problem on their 340. It would be a shame to have to run the boat below planing speed just to get some peace & quiet.

Keep the responses coming guys.... in the meantime, CRACK-CRACK-CRACK. :grin:
 
For what its worth, I have that same noise on my 260 Sundancer. You could not have described it better, it is quite a noise. it sounds like the boat is splitting in two. My sound comes from the windsheild area under the dash board.

I talked to my sales person at Sea Ray and he said it is normal. I will pay attention to this post to see if there is anything I should be worried about.

If it's normal, ask him to explain it to you. He should be able to understand normal stuff. It's the abnormal things that are tough to explain.
 
A couple of things. First, you should not sit on the toilet seat while underway. Especially if you are the only one on the boat. Second, if Sea Ray says that a noise that sounds like your boat is splitting in half is normal, I'd start worrying that I just bought from the wrong manufacturer. Third, I believe that the head compartment is a module. It could be that the head compartment is rubbing against the deck or dash while underway. Have you tried applying firm pressure on all the walls from all sides while it is popping?
 
For the hell of it, try the mirror in the head. Mine is hinged at the top and small pieces of velcro at the bottom. The velcro wore out and the mirror was banging against the wall in rough seas. I replaced the velcro to keep it in place.
 
Jackson - Unfortunately it wasn't the mirror, I checked it. I also tried putting pressure on the walls of the lavatory to see if that would affect the sound - no luck. The walls of the lavatory are surprisingly solid, there just isn't a lot of flex there.

I'm wondering if there is a stringer under the dash that could be flexing or maybe a structural member that comes up from the floor (like the wall where they mounted the power switches in the cabin). :huh:

Anyone ever had the top part of their dashboard apart? I'm not even sure how it would come apart since there are no exposed fasteners, but surely someone out there has done it...
 
Did you try opening the access door under the dash and see if you can hear the noice any better. The access door should help you avoid taking the dashboard out, but if it comes down to it, there're only few screwses.

Alex.
 
Alex F-

Where is the access door you are referring to? On the port side of my boat, there doesn't appear to be any access to the underside of the dash. The top part of the dash appears to be a continuous piece of fiberglass from the windshield down to the cockpit sink and underneath in the cabin the area in question is the head enclosure. There are no access doors built into the rear or top of the head that I can see.

By the way I had the boat out again this weekend. While the chop in the river was mild, we did hear the "crack" sound again as we crossed another boat's wake. So it hasn't subsided, unfortunately.
 
Alex F-

Where is the access door you are referring to? On the port side of my boat, there doesn't appear to be any access to the underside of the dash. The top part of the dash appears to be a continuous piece of fiberglass from the windshield down to the cockpit sink and underneath in the cabin the area in question is the head enclosure. There are no access doors built into the rear or top of the head that I can see.

By the way I had the boat out again this weekend. While the chop in the river was mild, we did hear the "crack" sound again as we crossed another boat's wake. So it hasn't subsided, unfortunately.

Just A Splash,
My bad, I guess when I saw the word “dashboard” I automatically thought of starboard side and access panel under the gauges. I just read your original post more carefully and noticed that you had referred to the issue on the port side. Sorry, I misunderstood.
Alex.
 
I am new to this site and just purchased an 05 34' Sundancer. Has anyone figured out a solution to this yet. I have the identical problem. I used the exact same description prior to reading this. Techs have put some foam in behind the shower, but it did not resolve. They may have to cut inspection holes, but before they proceed, I would like to know if anyone has figured out the problem.
 
I have only recently heard this problem on my '07 340. I haven't had the chance to do recon on the issue yet, but I assumed it was some glassware in my kitchen cabinets banging (after asking someone to check the microwave door). Looks like it might be a larger issue :(
 
I have the exact same noise in rough water on my 05 340da. As described earlier in this thread, I assumed it was the head module rubbing/tweaking against the deck under the dashboard. It does sound awful but i have not noticed any problems showing up from it.
 
I have the same noise when going through rough seas on my 260.
it sounds like its behind the dash. Not a comforting sound and like others said.. its a fiberglass on fiberglass sound.
some screw probably popped off and 2 pieces rubbing together.
 
I also have a rattle noise behind dash on a 2005 260 DA. This only happens when I run at over 4000 RPM back down under 4000 goes away.Thought this might be a warning horn going bad. Any ideas?
 
RE: 2000 Sundancer 340 - 140 hours

We just took our new-to-us 2000 Sundancer 340 from Oriental, NC to Ocracoke, NC on the outer banks (our most ambitious trip to date). We were running about 10-15 kts in 3 ft seas and the boat was making a god-awful noise as it banged into each wave. Basically from the upper dashboard area, port side, forward of the cockpit sink and just a few inches aft of the windshield base, there was a loud "CRACK" noise each time the boat hit a wave. Keep in mind that this was not an otherwise uncomfortable trip so I don't think we were asking too much of the boat. But the noise was driving us all crazy, CRACK-CRACK-CRACK every other second!
I think the noise is emanating from something under the dashboard in that area, perhaps the interface with the forward wall of the lavatory underneath or some sort of bulkhead in that area. We tried putting pressure on the windshield, the companionway door and the top of the dash, but to no avail, the noise seems to be coming from two structural members rubbing together (like fiberglass on fiberglass) somewhere underneath the dash panel. Interestingly, the noise was much quieter from inside the cabin.

Before I ask my mechanic to take apart half the boat to find it, has anyone experienced this before? Any ideas on where to start?

Thanks for your responses, this forum is a great resource!
Has anybody figured this out! THIS CRACKING NOISE IS NOT "NORMAL". My 2007 340 Sundancer has same exact problem when waves strike the port side hull. Please call with any Helpful info. This needs to be right. Thanks. Steve 425-269-8235 12/25/17
 
I know this is an old thread but......has anyone figured out what the problem is? I have the same exact issue on my 2000 340. Very frustrating to say the least.
 

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