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-   -   Shaft turning while sailing, Perkins PRIMA 50M (https://www.cruisersforum.com/forums/f114/shaft-turning-while-sailing-perkins-prima-50m-152852.html)

Sea Scamp 11-09-2015 22:01

Shaft turning while sailing, Perkins PRIMA 50M
 
Hi
With my last sailing boat the prop turning while under sail was never really a problem, weather in or out of gear, due to the props small size and only being a two bladed job.
Anyhow Sea Scamp is fitted with a larger three bladed prop, and has no trouble at all at spinning the prop shaft, when ever under sail and in Neutral, which is good in a way the at least I know the engine beds are line up true.

Anyhow I have not even tried putting her into gear while sailing to stop the shaft from turning. Main reason being that I believe the gear box is hydraulic and it would not engage anyway, unless the motor was running or I shut the engine down while in gear.

Anyhow would be good to hear the different views on this, (especially from anyone who owns or owned a Perkins PRIMA 50M) as in the damage that may or may not be cause to the engine and or gear box, while the shaft is free wheeling, while under sail.

Cheers

Shane & Tracey

Sea Scamp 13-09-2015 05:16

re: Shaft turning while sailing, Perkins PRIMA 50M
 
Gee's I thought there would of been a few reply's to this thread already

Anyhow, when I was a much younger Tuna fisherman, working on some of the not so traditional tuna boats with twin screws, if we ever had engine problems and lost either the port or stbd side, we would have to tie off the prop shaft, to stop the shaft from spinning on the way back to port. Other wise the gearbox and sometimes even engine would suffer major meltdowns , mainly the main gearbox bearing would be the first to go.

Which brings me to Sea Scamps shaft turning, now I know she is not a tuna boat with twin screws, and I suspect that because she is a sailing boat, that the engine would of been engineered to allow for the prop to be turning while under sail, or even locked in gear to prevent it from turning without damaging the motor. but as she is only new to me, along with the tiny 50hp Perkins, I don't really no what the go is with her yet.



Cheers


Shane & Tracey

steve77 13-09-2015 05:24

re: Shaft turning while sailing, Perkins PRIMA 50M
 
My present boat has a Yanmar, but I did own a Moody 40 with a Perkins 4-108 and Hurth gearbox. It was 20 years ago, and I seem to recall the Hurth manual saying that free-wheeling the prop while sailing should not be done for long periods, and I think they defined that as greater than 8 hours.

Can you check your gearbox manual and see their recommendations?

Also, I'm sure some folks on this forum may be familiar with your gearbox if you give us the manufacturer and model.

Cheers!

Steve

2Hulls 13-09-2015 05:39

re: Shaft turning while sailing, Perkins PRIMA 50M
 
I have two Perkins Prima 50s, rebranded as Volvo Penta MD22L-B. I (and all other owners of MD-22's I know) would routinely put the transmissions in reverse to keep the props from spinning. Even Volvo folding props would freewheel above about 6 kts. But these are mostly saildrive installations and may not represent your situation.

The few responses to your question could be that folks with Volvo MD-22's don't realize where they came from....

Dave

Scaramanga F25 13-09-2015 09:11

re: Shaft turning while sailing, Perkins PRIMA 50M
 
If the manual says not to put in gear, you could install a shaft brake.
Looks like a small disk brake.

Sea Scamp 13-09-2015 09:23

re: Shaft turning while sailing, Perkins PRIMA 50M
 
Cool Thanks guys

I like the sound of putting it in reverse, I don't no why I have never thought of that, considering that's how I park my car on a hill.

I'm still not sure if the gears will engage without the motor running or even have any effect while there is no oil pressure.
Anyhow I will be back out on her in two weeks and I will try putting it into gear without the engine running and if that doesn't work, then try shutting the engine down while it is still in gear.

Thanks Much Appreciated


Shane & Tracey

Blue Stocking 13-09-2015 09:26

re: Shaft turning while sailing, Perkins PRIMA 50M
 
Global war almost started recently on this site over that very subject. The search function will bring up many thoughts. My Hurth gets locked in reverse when sailing, -- because it is MY transmission.

nigel1 13-09-2015 09:30

re: Shaft turning while sailing, Perkins PRIMA 50M
 
I have a Volvo Penta TMD 22 (re-badged Perkins Prima M80T), and I routinely put the transmission to astern when sailing. This locks the shaft. This can be done when the engine is off, no need to put into astern before shutting down the engine.

Mike OReilly 13-09-2015 09:33

Re: Sharft turning while sailing, Perkins PRIMA 50M
 
I have a Perkins 4.108 with a Velvet transmission. The three-bladed prop free-wheels once we get up past 4 knots. I can't brake it with the shifter; it will not engage when the engine is not running.

I'm told this is perfectly fine and normal for this transmission. I do find it a bit annoying b/c I can hear the shaft turning on quiet sailing days.

HappyMdRSailor 13-09-2015 09:43

Re: Shaft turning while sailing, Perkins PRIMA 50M
 
Quote:

Originally Posted by Sea Scamp (Post 1913360)
Cool Thanks guys

I like the sound of putting it in reverse, I don't no why I have never thought of that, considering that's how I park my car on a hill.

I'm still not sure if the gears will engage without the motor running or even have any effect while there is no oil pressure.
Anyhow I will be back out on her in two weeks and I will try putting it into gear without the engine running and if that doesn't work, then try shutting the engine down while it is still in gear.

Thanks Much Appreciated


Shane & Tracey


Shane,

Like everything else, there's a million opinions of what works for the masses...

I personally think you're on the very prudent track of
"not ignoring and due diligence research"

I've done it all ways, and it's different for different boats... Once upon a time early I was a "reverse guy" if in gear... But a few "suddenly need the plant" incidents prompted me to change to a "1/4 throttle always in forward guy"

On my one Perkins/WB plant (50) there was a shaft brake, but I didn't use it a ton... Fairly simple to fit either shadetree mechanic style, or kit...


Will watch the thread... good luck!

HappyMdRSailor 13-09-2015 09:47

Re: Sharft turning while sailing, Perkins PRIMA 50M
 
Quote:

Originally Posted by Mike OReilly (Post 1913367)
I have a Perkins 4.108 with a Velvet transmission. The three-bladed prop free-wheels once we get up past 4 knots. I can't brake it with the shifter; it will not engage when the engine is not running.

I'm told this is perfectly fine and normal for this transmission. I do find it a bit annoying b/c I can hear the shaft turning on quiet sailing days.

Mike...I think you'll find allowing little healthy growth on the prop will increase your quiet sailing days by at least a kt or so... :whistling:

jreiter190 13-09-2015 10:17

Re: Shaft turning while sailing, Perkins PRIMA 50M
 
Mike, you must stop the shaft from spinning while the engine is off if you have a hydraulic Velvet Drive, due to the fact that the tranny only gets lubricant when the engine is running. So, install a shaft brake and remember to release it before putting the transmission in gear or run the engine for several minutes every four hours or so to lubricate the transmission. I've seen many velvet drives burned out because of freewheeling, though, to my knowledge, no one ever knew how long it takes to damage the transmission. Play it safe and have a shaft brake installed.when the engine is off, you have no hydraulic pressure, so it is useless putting into any gear.

BentP 13-09-2015 10:36

Re: Shaft turning while sailing, Perkins PRIMA 50M
 
If you want to engage the gear to avoid the shaft from turning when under sail, it is normally recommended to put it in REVERSE. This is to avoid damage on the gearbox, which is not designed to have an axial trust pulling the shaft backwards, when in forward position. There is simply no trust bearing in the gear box for that.

chris95040 13-09-2015 11:05

Re: Shaft turning while sailing, Perkins PRIMA 50M
 
This seems to be a controversial issue for some (dumb) people.

Different transmissions, with dfferent designs, have different ideal operating conditions. Read your manual and do what it says.

Some folks should leave it spinning, or immobilize it externally. Some folks should put it in gear (maybe fwd, maybe reverse. RTFM.).

Some folks claim to know 'the answer' for you even if they don't know your transmission. Those folks should be ignored.

Chris151e 13-09-2015 11:05

Re: Shaft turning while sailing, Perkins PRIMA 50M
 
Hi Shane and Tracy,
My boat is a 36' Islander Freeport with a three-blade prop, Perkins 4-108 engine, and a Hurth transmission. These are the tags re the Hurth transmission that came with the boat in 1979. https://s23.postimg.org/ae0ayws9n/tra...nd_sticker.jpg
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