Slapping noise from waves on hull.

ROOSTER · 07-23-2008, 05:49 AM

I have a Marine Trader 36 (Blue seas 36 in Australia).Waves hitting under the side chines as they enter the water making a noise. As im sure other similar designed trawlers have this annoying problem. Does anyone have a solution to my sleepless nights ?*
**************************************

Steve · 07-23-2008, 06:06 AM

My wife uses those soft foam earplugs, it doesn't bother me but it seems to scare our dog.
Steve

Keith · 07-23-2008, 08:58 AM

More rum?

...or put the pointy end into the waves.

Chris Foster · 07-23-2008, 08:14 PM

I've been told (but never seen) that some folks with this issue have had the chines filled in - some combination of foam, filler, and fiberglass. You'll have water coming up higher on the bow since they do tend to deflect it. But the Grand Banks don't have the chines, and they don't have a lot of flare, either, and they seem to do just fine.

Friend of mine with a 32' Nordic Tug sleeps in the salon whenever there's any chop at anchor.

Marin · 07-23-2008, 10:26 PM

Actually a GB is a very wet boat. There's not a lot of flare to the bow so when quartering or heading into waves on a windy day the hull knocks the waves high into the air and the wind blows it all on board. In the short, steep wind waves we get on the inside waters of the PNW, even in a ten knot wind we have the windshield wipers going all the time.

Every person will have their own preferences. As long as we know we are securely attached to a heavy-duty mooring buoy we like it when it gets rough. We sleep much better on the boat when it's moving around and there's wind and water noise than we do when everything is dead calm and silent. But if we're anchored and the wind and waves kick up we tend to worry about staying put. But we've spent weekends on the boat in our home slip when winter storms are passing through with sustained winds of 35-40 mph and occasional gusts to 70-plus, and it's great.

Rollsdoc · 07-24-2008, 04:40 AM

Foam Noodles the kind with a hole through them. Thread a rope through them. Then fastem them at the waterline. Makesa differance but ya gotta pick em up before you move.

Puffin_NT32 · 07-24-2008, 08:01 AM

Most hard-chine boats will have some wave-slap noise, and it can be annoying depending on where your forward cabin berth is located relative to the chine. As mentioned, Nordic Tugs have a chine slap at anchor/mooring, and depending on your tolerance (or amount of rum), can be an issue. Moving from a full displacement sailboat (Island Packet) to a Nordic Tug in 2006, I was amazed at the amount of noise and resonance coming from the point where the water line meets the chine. After the first night on our mooring, I had to do something. Nordic Tug owners are familiar with a "wave-slap preventer", constructed with noodles sewn into sailcloth panels. I sewed together a preventer, and it works, but it was a pain to deploy, looked silly ("hey, what's that diaper on your bow"), and I didn't want that hanging under the bow if I had to get underway quickly. I had placed 4" of sound deadening foam in the bow, but that didn't do much.

Last year I filled in a 50" section of the chine using CoreCell foam, West epoxy, and carbon fiber tape. That eliminated the slap. I took photos of the wave deflection at various speeds betweem 6 and 14 knots, before and after the modifications, and there's no performance impact. NT's are semi-displacement hulls and will get up on plane. At over 8 knots the area filled in is out of the water. Nordic Tug hulls on the 32, 37, 42, and 54 share the same chine design and slap. Their newly designed 49 footer, available this year, has been redesigned to eliminate the slap issue.

FF · 07-26-2008, 05:17 AM

Anchor by the stern.

FF

Daddyo · 07-27-2008, 11:57 AM

I've got the same boat and have been considering applying some of the sound deadening paint in the forward area under the berths. Has anyone given this a try? I figure if you dampen the resonance in this area it should help a lot.

botemon · 07-29-2008, 08:34 PM

Greetings,
Slime Chap hey? I guess I would have to agree with Keith.* More Rum!
**** Seems to be a notorious problem with a hard chine boat. (Chine Slap).
So Keith did ya sell yer boat* yet?* Sorry about the (off topic).
Drink more Rum!!!!
Respectfully,
Ken
*

Keith · 07-30-2008, 05:02 AM

Nope, but I just listed it with Krogen's brokerage. Asking $259,000 now. Hopefully they can find a good buyer!