Shaft brake

Pat4324 · Oct 9, 2014

I have a 2001 B331. I've been putting it into reverse to stop it spinning for over 13 years with no problems.

Gunni · Oct 9, 2014

It depends entirely on the type of transmission. Wet plate and hydraulic cone transmissions can be damaged if left in gear with the prop turning.

Gunni · Oct 9, 2014

So you might assume that the manufacturer wants that shaft free-spinning during sailing - an indication that the transmission should not be in gear and loaded up by a shaft that is generating torque. ID the transmission and investigate relevant service directives. I agree that a rumbling rotating shaft is an annoyance, as is dragging a locked prop, that is why folding/feathering props are so popular.

Philip_Oceanis 361 · Oct 10, 2014

clausjepsen said:
I have an Oceanis 361 with af Volvo Penta and a 3 blade non folding propeller. Going for sail the drive shaft turns and make a bit of noise. I have read, that it is not wise to stop it by putting it in gear.

Should I make some kind of shaft brake, just leave it turning or get a folding prop.

I am only doing cruising, so loosing 1/10 of a mile does not matter for me.

How much will I slow down the boat, if I put a brake on?

Should I be concerned about the wear, when it is just spinning around?

First of all welcome aboard.
The following is from the Volvo Penta manual (MD2030):
"If the boat has a fixed propeller the control lever must be in the neutral position when sailing. If the boat has a folding propeller the control lever must be in the astern position".

And yes, it does makes noice when it turns! Last time going downwind in nearly 30 knots of wind and "touching" a speed of 8,9 knots (!!!!) I though that the rotating shaft was going to start flying....

PS: So how do you like your Beneteau Oceanis 361? And what size propeller do you have (just to compare with mine)?

Gunni · Oct 10, 2014

What they do not address in that article is sailing performance. It is generally agreed that folding / feathering props yield the greatest value (in addition to silence) at low wind speed sailing. The boat will sail in very light winds, and accelerate better out of turns. Note that when you lock a fixed prop you generate as much drag as the hull drag. That is very significant in light winds, less so as winds increase and the boat reaches hull speed. If you do decide to mount a shaft brake, make sure you have a system in place to prevent engaging the drive while the brake is locked down. The pro units have a brake release at the helm.

Philip_Oceanis 361 · Oct 10, 2014

clausjepsen said:
Hi Philip. Thanks. I am really impressed how easy and well sailing the boat is not to mention that it got space as many 40 footers. Really looking foreward to summer, where we are taking her down the coast to the Baleares Island and Gibraltar.

Sorry, I do not know which size my propeller is.

Yes the noise can be quite high. I read, that a guy used one of these self locking pliers, that he locked around the shaft. It would also be possible to use something from a disk brake on a bicycle.

As I read this fine article http://www.flexofold.com/upload_dir/docs/Test_YachtingMonthly_low.pdf
then the prop will take around half a knot when spinning and up to 1 knot when fixed. But when you are speeding 8,9 knots, then I would not mind loosing half a knot to get rid of the noise.

For me a quiet trip is better than half knot faster trip.

I like the price, reliance and simplicity of an ordinary propeller, so I am not going to change it to af folding one of any kind.

8.9 knots was of course extraordinary and with 30 knots gust! More common are speeds of 6-7 knots. I also like the simplicity of a fixed prop though a folding/feathering is always at the back of my mind (no, I don't usually race but I would like to see higher speeds).