2 bladed prop alignment

[splashman237]

I've always put the engine in reverse to lock the shaft but Yanmar strongly advise against it:

Advisory Number: MSA08-003:

DATE February 8, 2008 Dealers and OEMs
TO: All Marine Distributors
SUBJECT: Gear in Neutral While Sailing All MODELS:

All Sailboat Engines

We continue to get questions regarding the correct gear position while sailing with the engine OFF. This advisory is issued as a reminder; Yanmar requires that if sailing with the engine OFF (not running) the transmission shifter must be in the neutral position or internal damage to the gear or sail-drive will result. This damage will not be covered by Yanmar’s Limited Warranty. Please instruct customers and dealers who deliver the sailboat to the customer, of the correct (Neutral) position for the marine gear while sailing.

If the customer desires that the propeller shaft not spin while sailing, either a folding propeller, shaft break, or other suitable device may be used. However, Yanmar accepts no responsibility for the selection, installation, or operation of such devices. Please also refer to Marine service advisory “MSA07-001_Yanmar Sail Drive Propeller Selection” for additional information.

If you have any questions regarding this advisory please contact a Customer Support representative."

I never had a problem with my Yanmar, but some users have reported that, after a long sail with the stopped engine in reverse, the gear shift sticks and requires considerable force to free it.

Hurth/ZF allow using reverse to stop the shaft. VelvetDrive and other hydraulic boxes don't lock the shaft when in gear so you need a shaft lock if you want to stop it turning.

HMMMPH its a Yanmar , looks like a shaft brake may be required drat ... wonder what the reason for that advisory is ?

 

[Tranona]

HMMMPH its a Yanmar , looks like a shaft brake may be required drat ... wonder what the reason for that advisory is ?

This is an old chestnut - an is widely ignored. The advisory was issued in the US, as presumably at some point they had warranty problems and were protecting their backs. You will find many people lock in reverse as I suggested earlier. Although shaft brakes are commonly advised, don't think there are many commercially available!

 

[Twister_Ken]

This is an old chestnut - an is widely ignored. The advisory was issued in the US, as presumably at some point they had warranty problems and were protecting their backs. You will find many people lock in reverse as I suggested earlier. Although shaft brakes are commonly advised, don't think there are many commercially available!

And a shaft brake ain't exactly practical on a saildrive!

 

[yoda]

HMMMPH its a Yanmar , looks like a shaft brake may be required drat ... wonder what the reason for that advisory is ?

Used to find a piece of 2x1 wedged into the shaft coupling acted as a good brake. I do have a folding prop for sale...........

Yoda

 

[Tranona]

And a shaft brake ain't exactly practical on a saildrive!

Exactly - although the OP is talking about locking the prop vertically behind a keel so sounds like a long keeler so not a saildrive.

There is an American shaft brake, but I have never seen it promoted here. I designed one years ago, but all my knowledgeable mates in the trade told me to forget it - so I did. 'twas an elegant bit of kit, at least on the back of my envelope (or was it beer mat?)

 

[Spyro]

This is an old chestnut - an is widely ignored. The advisory was issued in the US, as presumably at some point they had warranty problems and were protecting their backs. You will find many people lock in reverse as I suggested earlier. Although shaft brakes are commonly advised, don't think there are many commercially available!

I've had my boat and Yanmar 2GM20 for 3 years the guy before me had it 20 He always locked the shaft in reverse as I do. I've never had a problem getting it out of gear. Much better than listening to the shaft spinning and wearing out any bits that wear out.
I must remeber to align my shaft as I'm out of the water now, never know when I'll need that extra 1/4 -1/2 a knot.

 

[splashman237]

Exactly - although the OP is talking about locking the prop vertically behind a keel so sounds like a long keeler so not a saildrive.

There is an American shaft brake, but I have never seen it promoted here. I designed one years ago, but all my knowledgeable mates in the trade told me to forget it - so I did. 'twas an elegant bit of kit, at least on the back of my envelope (or was it beer mat?)

Tried a search for a shaft brake, there are a few about but all seem to be for 'big' boats and are expensive -

http://www.shaftlok.com/
http://www.controlmastersinc.com/shaftbrakes.htm
http://www.dcsint.nl/pdf/sailboat.pdf
http://setsail.com/prop-shaft-brake/


the lump of wood sounds cheap, guess it wouldn't need very much -> 3x2 and a wedge , you do of course have to remember to remove it before firing up the Iron topsail , otherwise from my extensive scouting knowlege of rubbing twigs together .......

 

[Tranona]

Yes, the shaftlok is the one that seems to have been around for some time and aimed at the yacht market. However, such devices are not easy to install and operate. One of the main problems as you have discovered is devising a means of locking the shaft consistently in the right place if your objective is to have the prop vertical. The one I designed overcame this limitation, but might have had problems with release.

Anyway, the potential market disappeared (if it ever was there) with the development of effective folding and feathering props. You would be much better fitting a folding prop (if there is room) or a feathering 3 blader which will not only have less drag under sail but will improve motoring performance.

 

[splashman237]

Hmm what type and size shaft is the folder you have for sale ? 25mm perhaps ??

 

[Tranona]

Hmm what type and size shaft is the folder you have for sale ? 25mm perhaps ??

I don't have one for sale! (although I have one on my boat - and a feathering prop on another boat). Flex o Fold and a Featherstream, both from Darglow Marine but there are plenty of others on the market.

 

[splashman237]

Used to find a piece of 2x1 wedged into the shaft coupling acted as a good brake. I do have a folding prop for sale...........

Yoda

Sorry it was Yoda had the prop for sale - Yoda PM me if its a 25mm dia

 

[fisherman]

Why don't you fit a big v pulley on the shaft and drive an alternator off it and let it spinto keep power up when sailing. You could always put a brake on the pulley if desperate.