Re: Speed sensor rubber cap

Stefan Jeukendrup

Hi Mohammed,

The function of the cap is to protect the underlying high impedance crystal on which it is glued. That keeps the water and dirt out. 

If your Sonicspeed still works first check AGC and resistance, see the manual in the "files" section.

If still ok I would not try to put the cap back. Instead you could try to fill the hole where the cap was with underwater silicone. The "art" is to make good continuous accoustic contact with the exposed crystal.

Hope this helps you,

Stefan Jeukendrup
sv Malaka Queen 
SM2k #348 @ Northern Ireland

Op 26 sep. 2021 07:41 schreef Mohammad Shirloo <mshirloo@...>:

Does anyone know the function of the rubber cap? Is this for prevention of damage or growth on the main sensor, or does it have some other functional role?





Mohammad and Aty

B&B Kokomo

Amel 54 #099


From: <> On Behalf Of CW Bill Rouse via
Sent: Sunday, September 26, 2021 12:33 AM
To: Notification <>
Subject: Re: [AmelYachtOwners] Speed sensor rubber cap


I had exactly the same issue. My sonic speed stopped working. I dove and found that I had one big barnacle on the rubber cap  When I pulled on the barnacle the cap came off.


Amel told me to reattach it with silicone sealant on the edges. 


I didn't haulout to do that and waited for about 6 months for a scheduled haul out. I replaced the cap, but Sonic Speed never worked. 


Good luck!


CW Bill Rouse 
Amel Owners Yacht School
+1 832-380-4970 | brouse@...
720 Winnie, Galveston Island, Texas 77550 
Yacht School Calendar:



On Sat, Sep 25, 2021, 3:48 PM Mohammad Shirloo <mshirloo@...> wrote:

Our speed sensor was a bit erratic after a 3 week stay in Venice. I dove in it today to clean the rubber caps with my diving gloves. The rubber cap came off of the forward sensor and I was able to catch it before it went to the bottom. 

I need to put the cap on while in water, until we haul out next year. It appears to be just a pressure fit as I could not see any sealant. The sealant may have just worn off in the past 12 years. Any advice on how to fit it back in under water, would be appreciated.

i have added pictures of the part to be reinstalled.

thank you.

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