Re: Prop is spinning freely


 

Thanks for that, Danny. I was told the same thing by Yanmar. However, I am reluctant to repeat it because I assume it will depend on the transmission installed on the engine. And to further confuse the issue Volvo and probably others have moved to electric gear changing transmissions which I assume require the ignition to be ON.

This is the reason I don't recommend it. ūüėÄ

Best,

CW Bill Rouse 
Amel Owners Yacht School
+1 832-380-4970 | brouse@...
720 Winnie, Galveston Island, Texas 77550 
www.AmelOwnersYachtSchool.com 
Yacht School Calendar: www.preparetocastoff.blogspot.com/p/calendar.html


   


On Mon, Jan 4, 2021, 2:00 PM Danny and Yvonne SIMMS <simms@...> wrote:

Hi Bill,

Volvo recommend either freewheeling or in gear. However care needs to be taken that either forward or reverse gear is selected depending on which firmly stops the spinning, the wrong one will allow slow revolution of the shaft from partially closed clutches which of course will cause wear. How to know which? When sailing observe the shaft rotating, put it into gear, the correct one will produce a satisfying clunk and the shaft will stop, the wrong one will slow the shaft but not fully stop it.  

Regards

Danny

SM 299

Ocean Pearl

Mangonui New Zealand

On 05 January 2021 at 04:45 CW Bill Rouse <brouse@...> wrote:

Chris,

There is usually not a simple answer to your question. 

 The most common issues for non-braking are mechanical within the caliper mechanism. Non-braking is usually caused by the following in order of probability:
  • The caliper bushings will wear and cause misalignment and open calipers
  • The brake shoe pads will wear
  • The caliper frame may be loose on the hydraulic cylinder
  • The hydraulic cylinder spring may need adjustment
  • The hydraulic cylinder may need an overhaul
  • The caliper mechanical springs may be broken or defective
  • Or, something else I haven't thought of¬†
The most common issue for not releasing is hydraulic in nature.

The quarter that Courtney refers to will usually solve the problem when the bushing is worn, or the brake pad is worn.

It is possible that the Italian-made Caliper you have is no longer made. If so, Amel will supply you with a new model that will work, but not necessarily fit without minor modification.

I believe that you can either leave the prop free spinning or place the transmission in gear to stop the spinning, however, I do not recommend either of those because I have not been able to verify the long-term issues, if any, in doing either.


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


On Sun, Jan 3, 2021 at 9:37 AM Chris Likins < likinsca@...> wrote:
We have A54 #133. Today when sailing I noticed that the prop was spinning freely(in reverse) each time a wave would pass under us. It’s easy to see that the shaft brake is not engaging when the engine is in neutral or shut down. Referencing Bill Rouses book p.305, it reads that the hydraulic shaft OPENS the calipers when pressurized by the transmission. Currently the shaft is retracted into the piston at all times allowing the calipers to remain open. I understand that the calipers are supposed to spring shut on the disk when transmission pressure is lost on the shaft. I am a bit confused by this as there is no mechanical connection between the hydraulic shaft and the outer caliper. It seems like the calipers should close when the shaft is extended.. So my questions are
1. Can someone help explain this system in more detail? 
2. What position should the shaft be in when pressurized and not pressurized? 
3. Is it most likely a bad spring on the caliper? 
4. Most importantly for now.. Is it ok to allow the prop to spin freely for the duration of the passage or would it be better on the shaft if we remain in forward gear. 

Thank you for the help! 

 

 

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