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Home >> Technical >> Boat Hum Excessive
Here is the video of my foils humming.

https://www.youtube.com/watch?v=A5vPGcOj9BI

Also, my foils at the leading edge have quite uneven bond gaps. At some points the gelcoat seamless joins and at other points there is a 1-2mm gap.


Reply
06/04/2021 03:26:00
mob
Posts: 38
Today I went out in 20knot winds, and it was very evident that my rudder was vibrating. I also think a little bit on the daggerboard but adjusting doesn't cause much change. 

Before I went out I discovered some imperfections and the corner edge was not bonded correctly. Looks like bubbling is also occuring and tapping in certain places sounds almost hollow (air pockets?)

The humming on mine also starts at very low speeds and even up wind, which 100% did not occur before. 

I suspect those that are experiencing hum is due to recent manufacturing issues with foils, maybe the bond / materials used isn't up to quality which causes this. Perhaps only some may experience it if they are unlucky to get a bad foil.

I can't guarantee anything but seems like contacting RS to get replacements when available (after swapping supplier) is best way forwards. Hopefully RS will be supportive of replacements considering there is a clear issue.

---

Also wow Areos seems to be flying of the shelf, I only got mine the week before. Mine was 3600. That's a large amount shipped is such a short time period. That is good to see though. 




Reply
05/04/2021 22:45:00
Blake Newman
Posts: 19
My latest boat's blades hum as well (unlike my prior two). Thought it was only me experiencing this...

Marc Jacobi


Reply
05/04/2021 20:15:00
heymatey
Posts: 28
I received my new boat (3656) last week, sailed for the first time at the weekend.   Exactly the same issue, a loud humming, something I didn't experience at all with my previous boat (2553).  Interestingly I have the humming at low speeds as well as high (3knts+, something like that).

In a way it's reassuring to hear that others have the same issue, and it isn't particular to my boat.  I'll raise it will RS in the morning.


Reply
05/04/2021 11:37:00
Mark R
Posts: 9
Yes, when I swapped with my previous boat 2500, the hum disappeared.

I've tapped all along the gelcoat and I can't detect any obvious voids. However, the gelcoast could well be "unbonded" to the core and I would not know.

It could be a batch issue as quite a number of boats from the same batch have the issue here.

We're going to try testing a set of foils to see which ones hum and which ones are silent. Fingers crossed.

Michael


Reply
04/04/2021 08:03:00
mob
Posts: 38
But that was for a specific imperfection rather than the entire length of the foil. So I don't think the 3mm rule can be ignored.


Reply
04/04/2021 08:03:00
mob
Posts: 38
https://www.rsaerosailing.org/index.asp?p=forum&fid=12&tid=8662

I found this post, and imaged is a foil with a 6mm bevel. 


Reply
04/04/2021 07:37:00
Blake Newman
Posts: 19
Mob,

So when you swapped your rudder for your old one did the hum disappear? Sounds to me that there could be issues with the gel coat bonding of the foils. 

The damage to the centerboard I had within minutes of sailing in a moderate breeze, correlates to there questions they asked you. If they have had a supplier issue and the quality of the bond isnt correct then this can also cause vibrations based on my knowledge. If adding a bevel doesn't resolve then I can only imagine the foil has imperfections that we can't correct. 

Since the damage the daggerboard has almost fully delaminated away from the core. 

I guess my best advice would be to keep in contact with RS after sales and they may be able to sort a replacement after they correct the supply issue. It probably hasn't affected everyone as evident that peters boat not experiencing the same issues with hum.


Reply
04/04/2021 07:14:00
Blake Newman
Posts: 19
A bit more data: My 3414 centerboard and rudder did not have any asymmetric bevel when delivered. It was rounded and looked like it just had a bit of sandpaper run over the trailing edge. My first Aero 1250 centerboard had a very marked asymmetric bevel. The second Aero 2500 had a bevel too, but less. The 3414 boat eliminated the bevel completely.

However, I've since put a 3mm 30 degree bevel on both foils and the problem while reduced a little, is still there.  I took great care and made a jig to achieve a very even, 3mm bevel at a constant angle. I'm reluctant to increase the bevel beyond 3mm and would need advice from RS that this is required.

RS have asked I check for voids and places where the gelcoat may not have adhered to the core. I've tapped around and do get some varying sounds, but I can't determine if the gelcoat is adhered to the core or not. It has not delaminated in any spots.

I understand that some hum is normal at speed. But this is well beyond that it starts at about 12kts of breeze or when you are just about to plane.

I've got a cool video that shows how loud it is and the vibration can be felt through the hull and tiller. I seriously doubt that the turbulance caused by this can be fast.

Other than this, my 3414 boat is perfect.


Reply
04/04/2021 01:26:00
mob
Posts: 38
Peter,

Thanks, yeah it's been a bit problematic but as mentioned mistakes happen. Can only look forward.

The dagger board I have now is second hand, but it could be what you say. As I don't know how old it is. It will be replaced soon enough when RS are able to, which is fair enough. 

Does this also apply to the rudder and would this cause same affect. If so it could be that I'll inspect tomorrow, but it did seem as though the alignment wasn't perfect with initial eyeball. 

Atleast Im reassured that I'm not going crazy, and i can inspect further workout the issues.

PS, I don't want to be the horrible reviewer that gives 0 stars. RS support has been awesome and they are super helpful. The reason I posted here was do get a feel of the situation and if I was unlucky or if there is others experiencing the same. Overall talking about these things will help the class move forward and surpass these issues. 



Reply
04/04/2021 00:07:00
Blake Newman
Posts: 19
Hi Blake,
Congrats on your new RS Aero and sorry to hear of your issues.

Both RS Aero foil trailing edges' are built asymetricly to avoid hum.
I suggest you check the trailing edge of your daggerboard to see if it is asymetric like your last one, or not.

I have a new RS Aero as of 3 weeks ago and all is fine with it after 4 sails.


Reply
03/04/2021 23:56:00
Peter Barton
Posts: 3166
RS Did admit to supplier issues and are replacing my daggerboard with a new one upon change of supplier. They sent me a second hand one (although pretty new looking a few scuffs here and there), to get me back on the water ASAP. 

This is a shame to hear as this is a significant batch size of foils (and possible hulls) that are not fit for purpose if the case. I don't know how many could be affected. My pervious boat No was 3148, and had no issues what so ever from my memory. In a way it feels like I could have traded down. I did put my previous boat through its pace last year due to the UK storms but she was much loved and cared for but an upgrade after a rough year sounded like a worthy decision.

I know RS are shipping RS Aeros like crazy so perhaps they attempted to find a suppler to meet demand but had problems. Especially as lots won't be able to sail it may be hard to spot imperfections and issue until they feedback loop opens up. 

If this issue is quality then I would like to see RS taking action to rectify and replace any foils that occur defects. 

Humming may not make the end of the world but it does mean the boat isn't as happy as it should be, and our RS Aeros deserve to be in top form. Otherwise we are not an equal class. 

Ill contact RS team to notify them that I'm still concerned, but it's worth raising at a association level that quality is slipping and it's not in the owners interest to be the recieving end of this. I'd expect the opposite that over time quality issues become a thing of the past and we move forward but seems we have taken a few steps back based on my recent experiences. 





Reply
03/04/2021 23:37:00
Blake Newman
Posts: 19
I've experienced extrem hum in my latest boat 3414. I've had 2 Aeros before this 1250 and 2500. It is bone jangling in 15-20 kts of speed. The tiller vibrates and boats nearby have complained about the noise!

I've tested replacing the current foils with my 2500 foils which were silent. So the issue is definitely the new foils.

The trailing edge is different on the 3414 foils compared to 2500. I've tried (with RS instructions) to bevel the trailing edge and it has helped a little.

We have 6+ new boats here that have the same problem. 

Something has changed in the manufacture of the foils -- the previous ones did not have this problem.



Reply
03/04/2021 23:24:00
mob
Posts: 38
Hope everyone is doing well, especially during this tough time. 

Recently traded in RS Aero, upon receipt of new boat the build quality hasn't been great. The first hull had to be replaced due to imperfections. However RS where great in facilitating this so due credit there - life happens and things do go wrong. 

On the maiden voyage, after the replacement, last Monday. I noticed a strange hum (super excessive) The daggerboard delaminated and gel coat pealed back. RS again jumping straight in to rectify the problem and replace the foil. So despite the issues I'm being looked after. Although the problems I'm glad RS have been open and transparent and immediately sorting things out.

However today, 12 knots gusting 16-18knots wind. I still had humming from the boat. Which I'm pretty sure didn't exist on my first RS Aero. Or atleast until I was hitting very fast speeds 15knots+. 

Its been so long since I've sailed (lockdown) maybe I'm just over analysing things considering the quality issues and I'm hearing humming that should be expected at ~11 knots. However at same time I feel the hum is far too pronounced and is almost like a laser which I know the RS Aero is known to be better for.

Normally humming is due to foil issues; alignment, imperfections or not fitting the casing correctly. Although it can also mean a warped hull (I hope not). Although everything looks pretty on par and I'm struggling how to diagnose or if I'm being over analytical of the situation I'm in. 

The only things I've noticed are:
  • There is a small gap in the under gasket for daggerboard case at the fluff towards the stern side (3mm at most). Could water be jetting up there causing this to happen?
  • The rudder foil could be imperfect, the trailing edge (black part) is about 3-4mm longer one side than the other. Could it be that this imperfection causes enough imbalance to cause an excessive hum. 
So my questions are...
  • Does anyone experience hum, if so what speeds does this occurs?  Id imagine there is a limit to which all boats under some stress will hum
  • Do you have any tips to identify hum issues, and how to rectify?
  • Has anyone experienced recent build quality issues? or am I just unlucky.


Reply
03/04/2021 23:19:00
Blake Newman
Posts: 19


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