Hull slapping on chine

jimbobio · 10-01-2020, 09:25 PM

Hi all...

I am hoping to join the world boating (again) soon ....I’m sure there are a few Beneteau owners (41s or 44s) that might be able to address my concerns regarding “hull slapping on the chine” and any good or bad experiences with this phenomenon on the Swift Trawlers...

Thanks for any responses in advance..

Jim Nelsen
Jim.nelsen@yahoo.com

catalinajack · 10-02-2020, 01:27 AM

You might ask Mainship owners also.

Quote:

Originally Posted by jimbobio

Hi all...

I am hoping to join the world boating (again) soon ....I’m sure there are a few Beneteau owners (41s or 44s) that might be able to address my concerns regarding “hull slapping on the chine” and any good or bad experiences with this phenomenon on the Swift Trawlers...

Thanks for any responses in advance..

Jim Nelsen
Jim.nelsen@yahoo.com

Comodave · 10-02-2020, 02:12 AM

Welcome aboard. That is one of the reasons we have a master aft cabin...

rslifkin · 10-02-2020, 07:26 AM

Almost any hull that can plane will have chine slap. My boat does it quite badly, enough that I can hear it in the aft master. But it's not loud back there, and it's pretty easy to get used to. It's one of those sounds that very quickly becomes a "normal boat sound"

Mr. Blu · 10-02-2020, 09:46 AM

I know a guy who bought a second hand Beneteau Swift Trawler 52, used it one day and then got back to his broker with the request to sell it, because he couldnot sleep for all the noises that the water made. Since then he sleeps in hotels in the marina's he visits.

For me the noises are a part of being on the water, it "rocks"me into sleep.

boatpoker · 10-02-2020, 10:53 AM

Have a buddy down the dock that had hard slap near the bow.
Won't work for everyone but he solved his issue with strategically placed pool noodles.

ScottC · 10-02-2020, 01:52 PM

You might find this thread interesting:
https://www.trawlerforum.com/forums/...+slap+beneteau

Guero_Loco · 10-02-2020, 02:42 PM

What's the scoop on SlapSilencer?

Nomad Willy · 10-02-2020, 04:13 PM

Doing something about chine slapping needs to be done before purchase in selecting a boat. Probably almost any buyers broker would advise a client about chine slappers.

Once you’ve got one get used to it. Or sell.

catalinajack · 10-02-2020, 07:09 PM

I travelled on the Great Loop with a guy who had a Mainship. The slap drove him crazy. He sold the boat as soon as he completed the Loop. Nomad is correct. Either get used to it, wear ear plugs, or sell the boat.

Quote:

Originally Posted by Nomad Willy

Doing something about chine slapping needs to be done before purchase in selecting a boat. Probably almost any buyers broker would advise a client about chine slappers.

Once you’ve got one get used to it. Or sell.

Frosty · 10-02-2020, 07:46 PM

This is probably obvious (to everyone else), but I want to check something. Pretty much any boat on my possible list does not have an aft cabin (I like cockpits), so I'll be sleeping in the bow.

I get that a hull like (just to pick one example) a Nordic Tug 32, that has the forward chines (if that's the proper word, but what I mean is they are built into the hull vs. added on pieces) is going to get hull slap.

Is the corollary to that that a boat with a smooth transition at the bow will not (or at least not any more than just the normal sound of waves on the bow)?

I listened to a recording of "before" and "after" from an owner who filled in the forward chines/strakes on his Nordic Tug, and the "before" was really obnoxious (to my ears). Much more than just hearing waves lapping at the hull.

So long question short: If I seek out a boat with a "smooth" bow around the waterline, will I avoid the truly bad slap?

Northern Spy · 10-02-2020, 08:02 PM

Some Nordic Tugs owners have filled in (with glass and foam) the chine above and just below the waterline at the bow.

https://www.sentoa.org/maintenance_t...ine_nt_32.html

I just got used to it.

Frosty · 10-02-2020, 08:23 PM

Understood, and it's possible I would get used to it too. Or decide that a given boat had enough other good attributes to ignore it (such as your sweet N26)

But a few people above expressed that one way to deal with it was to buy a boat that didn't do it in the first place, and I'm just trying to ascertain the cause. I see that a Nordic Tug (not to pick on them; the reason I now this is that I do like them!) has a "formed in" strake or chine (not sure which you'd call it) such that there is a little "ledge" in the hull right at the waterline in the bow. I believe this is what causes the slap.

So.... does that mean that on a bow that is smooth (without that chine) at the bow waterline will not make the slap? Or just how does one avoid it in the boat selection process as Willy suggests above?

Arc · 10-02-2020, 08:41 PM

You guy just aren’t tired enough. A couple shots of rum and the slapping goes away.

kthoennes · 10-02-2020, 10:45 PM

Or bourbon. Seriously though, I'm surprised wave slap comes up so often. Sleeping on the boat is an orchestra of noises - creaking mooring lines, the A/C running at the slip (including the sound of running water all night), the refrigerator kicking in, nearby sailboats with rigging clanging against aluminum masts in the wind at night, or wind whistling in the rigging, the dingy bumping against the swim step -- or when we boated New England, buoy bells clanging, seagulls screeching. Heck, wave slap is a lullaby.

Comodave · 10-02-2020, 11:00 PM

Our aft cabin must be very well insulated or something. We were tied up on the Hudson about a hundred yards from the commuter train station that runs to NY. We were worried that the trains would keep us up all night. We really didn’t notice the trains at all during the night. Much less wave slap.

BruceK · 10-02-2020, 11:51 PM

Hard to describe, but if you can see a recess or pocket where the chines start, at water level,you can see where waves would strike and resonate. I believe Mainships were identified as "slappers", maybe look at one and see if what I remember is borne out. As to the ST42, I was interested in one but passed for other reasons, it may have been identified as a "slap" candidate, I can`t recall for sure.

ScottC · 10-03-2020, 10:52 AM

Earplugs.

firehoser75 · 10-03-2020, 04:33 PM

Frosty and OP,
Nordic Tugs, due to their bow structure can experience wave (bow) slap. We have had a couple of nights where it was terrible, but mostly you can get used to it.
Several NT owners have spent (a fair bit of) money getting some permanent, fibreglass work done to the bow area and have reported great success in reducing or even eliminating most of the noise. It is my understanding that the NT bow design is supposed to reduce waves (green water) over the bow and making a "dryer" boat. I don't know this as fact however, and I have not heard of any owners who have "adjusted" their bows for wave slap, complaining that they noticed more water over the bow or any noticeable drop in performance.
For us light sleepers, ear plugs do help.

Art · 10-03-2020, 06:16 PM

Amongst other boats in our family... We had a "Johnson Bros" lapstrake wood boat. That lasted for only one season in NY. Dad went crazy hearing the slap on the strakes; he and mom slept in the forward berth.

Different than chine slap... in that: Chine slap is one to three or maybe four rather loud knocks per wave contact. And, lapstrake is a bunch of lesser noisy, but many more multiple knocks as well as sort of a suction sound as the wave travels up and down the non chine lap strake hull sides.

Thanks to master cabins in rear the chine slap is no problem.