Chine Slap noise ST42

We love our vessel very dearly and spend a great deal of time aboard cruising around the North East coastline of New Zealand from our home base in Auckland.
When anchoring overnight we do go to some trouble to tuck well in to the weather shore if there is any breeze. We find that even a small chop generates what we call the Arrival of the Slappers. Sadly these are not fast young ladies but slapping noises from the chines. These are amplified by the hull acting as a sounding box and can result in a disturbed night's sleep.
I believe that this is a common problem on semi-displacement vessels and have observed some Mickey Mouse attempts to overcome this by attaching floating Noodles and other objects when at anchor.
I am looking for a more professional solution such as a partial infill along the chines. I understand that the main function of the chines is to deflect spray rather than to have a hydro-dynamic effect.
Any comments or advice from other owners would be most welcome.

Common problem. My little 38 has spray rails on the chine and a little chop rings it like a bell. If you have aft cabin (I do not) that will be better for sleeping. At times I have put a "monkey line" on an aft cleat and noosed the anchor line. Pulled it a$$ end to the chop. It works.

With hulls designed to move through water by ME's it is usually not their concern as to slap noise while at anchor.

That said... there was a manufacturing hull design alteration accomplished for some Tollycraft models' chines in the early 1990's (I don't recall the trade mark name of it) The change was meant to improve stability while boat was moving as well as being expected to reduce fuel usage by limiting hull-surface contact at planing speeds. Well... evidently that did create quite the hull slap while at anchor; Tollycraft soon stopped producing that hull design. From what I saw on another forum, some Tolly owners filled in the chine areas and that stopped the at-anchor slapping noise. None that I recall mentioned any reduction in hull performance.

Side note: Back when... Dad purchased an early 1960's wooden, "lap-strake" 32' Johnson Brothers planing hull boat. Our family only used that boat for one full season in NY. Why - slap noise at night was a b-i-t-c-h! LOL Reminded us all of a washboard with hand turned over having fingernails being strummed up and down... all night long, in any ripple or waves at all!

I've grown to like that sound and it puts me right to sleep. Unless it's a heavy slap and real loud.


A few years ago I saw a Marlow Explorer in a boat yard that was having the chines ground off and filled in, just to reduce the chine slap. The guy in the yard said they do that to a few boats a year and the people who have had it done seemed to be happy with the results.

My thoughts are similar to GFC. We enjoyed the chine slap but saw several boats over the years getting the chines filled. Easy money for even a newbie fiberglass person.

Get a couple estimates and fill them in at your next haul out.

Ski in NC said:

Common problem. My little 38 has spray rails on the chine and a little chop rings it like a bell. If you have aft cabin (I do not) that will be better for sleeping. At times I have put a "monkey line" on an aft cleat and noosed the anchor line. Pulled it a$$ end to the chop. It works.

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This works it is also used more often to keep a boat from rolling where the wind and wave angles are different enough to cause waves to broad side a boat. Adjustment of a mid or aft cleats line to the anchor line forward of the boat can bring and keep the bow into the waves were now you only have to deal with bow slap. That's why I carry good ear plugs.

I've seen a prior post by TFer that did a fill and posted pics...try some searches.

Thanks to all for your comments. I think that short term a couple of rums before turning in and ear plugs may help. Longer term I will research fitting some form of filler and will post the results once completed. Happy Cruising to you all.

Ear plugs work. And have the added benefit of blocking the noise from bozo who decides to run his generator all night in an otherwise quiet peaceful anchorage. Not too mention the 24 footer with 12 people, 6 cases, and 4 speakers, but they usually leave once everyone falls in and after the wet T shirt contest ends around 10PM.

I buy the magnum jar of 33NRR ear plugs. no slap. no howling wind. no drama.

Florence said:

Thanks to all for your comments. I think that short term a couple of rums before turning in and ear plugs may help. Longer term I will research fitting some form of filler and will post the results once completed. Happy Cruising to you all.

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Not sure if this approach would be possible in a near new boat, but when I relined our front cabin because the teak veneer had got water damaged under previous owners, I took the chance and packed fibreglass insulation batts behind it all. This reduced the wave slap to a very low level, with other temperature insulation and condensation prevention benefits as well. Would it be possible to get access behind the cabin lining enough to push batts in, or maybe use that expanding foam type of filler, which spreads a long way from quite small entry points..?

SoWhat said:

Ear plugs work. And have the added benefit of blocking the noise from bozo who decides to run his generator all night in an otherwise quiet peaceful anchorage. Not too mention the 24 footer with 12 people, 6 cases, and 4 speakers, but they usually leave once everyone falls in and after the wet T shirt contest ends around 10PM.

I buy the magnum jar of 33NRR ear plugs. no slap. no howling wind. no drama.

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Also, Little to no chance to hear distressful items that may happen over night. When aboard, I always sleep with eyes, ears, nose tuned-in for the what ifs. I usually rise at least twice during night to simply go into salon for brief look/listen/smell... then back to bed. Some call me parodied. For me, I call it feeling very comfortable while remaining carefully safe! When I am Captain, "The Buck" stops at me!!

Art, those two trips to the head every night have nothing to do with boat safety.

CPseudonym said:

Art, those two trips to the head every night have nothing to do with boat safety.

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Ta heck with the head... It's over the rail at 2 AM... that way, can really see and hear what's happening!! LOL

Don't arrest me!!

Florence, have you approached Beneteau about this? They may have a solution, Doubt yours is the first complaint.
It may relate to hull thickness as much as design. Some boats transmit, some don`t. My previous boat did to a degree, this one does not, hull is 1" solid f/g. A neighbour with a Dyna 45 can`t sleep in the fwd cabin for "the slap".

Our new boat has a very loud chine slap too. Honestly, there is really little to nothing that can be done about it. We were so scared it was going to force us to reconsider this boat. However, after a few weeks/months, we have gotten used to it. Like bad music piped in at the mall, we just don't hear it anymore. Not much anyway. There ARE those nights when the wind really chops up the marina, but even then, we still find ourselves able to get as good of a night's sleep that you can get on a boat.

I used to have the pictures of the guy who filled in his chines. I don't know if I still do, but I will try and find them later this week.

Art said:

Also, Little to no chance to hear distressful items that may happen over night. When aboard, I always sleep with eyes, ears, nose tuned-in for the what ifs. I usually rise at least twice during night to simply go into salon for brief look/listen/smell... then back to bed. Some call me parodied. For me, I call it feeling very comfortable while remaining carefully safe! When I am Captain, "The Buck" stops at me!!

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Finally I have a legitimate excuse to justify those middle of the night trips. Thank you Art.

So I DO still have the pics of the guy who filled in his chimes on his Nortic Tug, but it is in a PowerPoint prezo. So I will need to export it to individual frames. Give me a few days.

I spent a couple of months last summer aboard my new-to-me old Mainship 34. The first few nights I wondered how I would be able to sleep. By the end of the summer I just took it to be normal. Kind of like halliards rattling in my old sailing days. I came to love that sound.

Jeff F said:

I spent a couple of months last summer aboard my new-to-me old Mainship 34. The first few nights I wondered how I would be able to sleep. By the end of the summer I just took it to be normal. Kind of like halliards rattling in my old sailing days. I came to love that sound.

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Yes, that happens all right. I have now got so used to the small residual slap we get since I added the insulation referred to in post #10 above, I tend to wake up with absolute silence now.

Peter B said:

Yes, that happens all right. I have now got so used to the small residual slap we get since I added the insulation referred to in post #10 above, I tend to wake up with absolute silence now.

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Right. I would never be able to sleep with earplugs. Would much rather be tuned into the normal sounds, which with time and experience allow monitoring of the conditions from under the blankets

Hi folks,

While I can certainly commiserate with the OPs problem (I've posted about it myself), I think that Art has hit the nail on the head. At least one person needs to sleep with all senses unimpaired. See my post about anchor dragging, it was hearing the waves breaking on shore that allowed us to avoid tragedy. My wife and guests can use ear plugs, and I carry them aboard for all to use. Just not me, as I am Captain and responsible for all onboard.

Good luck with finding a workable solution. Please let us know what you end up doing.

Cheers, Bill

Chinese Slap

Hi Florence,

Sorry, auto correct on the title! Chine Slap us what it should say. (Since corrected)
We have met on the pontoon when you stopped by at Westhaven last year.
We have just sold our corsair and are looking at a Swift.

Chine slap is a common problem for the European boats. They don't anchor off all the time like we do.
The Salthouse was superb in this respect and was as silent as a yacht.
All that Bob Salthouse did was to fair the chines at the waterline. That's what we'll be doing if we get one.

A quiet night is a must and looking for a spot right by the beach is a pain.

Cheers
Clive

Wearing ear plugs on boats while sleeping is not too different than wearing dark sunglasses at night while piloting the boat... you can bet your bum bum that you will miss something, probably more than one thing, and, maybe, eventually... something very important.

Hey, here's one solution to your problem. I sleep like a baby, after a wave of rhythmic slaps, I have listened to all my life so it does not bother me. Another tips, learn how to love your country, do not think of it as a negative thing.


NENTOA Wave slap preventer




P.S you have very cool hard top, you fly bridge! you've built it, or?

Florence, may I suggest reading a chapter or two of "The Slap" by Australian author Christos Tsiolkas, or watching an episode or two of the film. About an annoying child at a party being slapped by someone not its parent, and what follows. Not sure if it will lull you to sleep but it will distract you from "the slap" currently bothering you.

Many thanks to all who contributed on this. On balance I think that we will accept the situation as is and not carry out surgery on our pride and joy. Also I concur that earplugs are only a last resort as when anchored I tend to be aware of any extraneous sounds which may herald a problem. We have just completed a summer cruise and have taken extra care in selecting anchorages which are likely to cause problems due to the dreaded Slappers. Cheers

Florence said:

Many thanks to all who contributed on this. On balance I think that we will accept the situation as is and not carry out surgery on our pride and joy. Also I concur that earplugs are only a last resort as when anchored I tend to be aware of any extraneous sounds which may herald a problem. We have just completed a summer cruise and have taken extra care in selecting anchorages which are likely to cause problems due to the dreaded Slappers. Cheers

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Believe us, you will get so used to it, that on those very still nights when there is no wave action and no slap, it will seem eerie and too quiet, and you'll have to get up to check you have not anchored too shallow and sitting on the bottom. (It does happen).

We used to live one time when I was young in a house in the country where a railway cutting went past the house only about 70 feet away. For a while it was a novelty to jump up and watch them go past - quite a few were still steam back then. After a while we often barely noticed when a train went by, but visitors would comment about "how does that noise not bother you?" and "how do you sleep through that?" But we did - soundly - in no time at all. It was reassuring to have the familiar sound, as if it was confirming all was right with the world. Chine slap same thing. All good, no worries...

You do get used to "an old slapper". And loud noises at night.

Swift trawlers have chine slap but those chines are important to stability. The 34 st is even worse than the larger trawlers. Yes you can fill them in at the waterline or just get used to it. We got used to it and i sleep better with than without it now!!!

Dynamat