Prop Issue or Slipping Saildrive?

[UFO]

I have a SD50 with Max Prop 3 Blade Easy Prop.


I have recently noticed on diving the hull that the prop no longer easily feathers and is Very hard to maneuver around by hand.


I also very recently had no propulsion on that engine a couple of times when I engaged forward - It revs up normally, but that's it.



When i take the revs up to around 2000 you can feel the drive engage and all runs as it should.


I obviously have an issue with the prop, but is it this causing the lack of propulsion or do I have a slipping cone clutch as well?

[tkeithlu]

Parsimony. The description you give could be accounted for by the prop not coming out of feather, and you already know that it is stiff. I suggest that you adopt that hypothesis (accounts for the phenomenon while assuming the least), and exhaust it as the cause before tearing up the tranny.

[fstbttms]

When was the prop lubricated last?

[donradcliffe]

The maxprop should be very easy to feather and unfeather by hand. If it has not been maintained, that explains all your symptoms. You can do it in the water, but it should definitely be done on every haulout.

https://www.p2marine.com/max-prop-gr...kaAnuvEALw_wcB

[Stewie12]

Definitely sounds like a maintenance job to me.

[jmschmidt]

Sail drives should be outlawed for all but racing boats which are haulout after each use. Sailors will learn this after a few more expensive years of babying these high maintence unreliable contraptions.

[ggray]

Certainly SDs have issues that need to be understood and managed. But they also have some advantages.

Same goes for shaft installations.

We have enough laws already....

[Cadence]

Originally Posted by tkeithlu

Parsimony. The description you give could be accounted for by the prop not coming out of feather, and you already know that it is stiff. I suggest that you adopt that hypothesis (accounts for the phenomenon while assuming the least), and exhaust it as the cause before tearing up the tranny.

[UFO]

Originally Posted by fstbttms

When was the prop lubricated last?

May 2021 - About 200 Hours of use ago

[ChrisseH]

Originally Posted by UFO

I also very recently had no propulsion on that engine a couple of times when I engaged forward - It revs up normally, but that's it.

When i take the revs up to around 2000 you can feel the drive engage and all runs as it should.

I obviously have an issue with the prop, but is it this causing the lack of propulsion or do I have a slipping cone clutch as well?

Sounds definitely like the cone clutch in the sail drive is slipping. I had the same symptoms in my SD50 some years ago. Disassembled the clutch assy and lapped the cone surfaces myself and the sail drive has thereafter worked well for 700 additional hours.

So I would take care of the slipping problem first and wouldn't be surprised if the slipping is the only problem. Please note that there are at least three threads on CF related to the SD50 cone slippage.

Br,
Christer

[stormalong]

Originally Posted by donradcliffe

The maxprop should be very easy to feather and unfeather by hand. If it has not been maintained, that explains all your symptoms. You can do it in the water, but it should definitely be done on every haulout.

+1


My Maxprop has never been difficult to operate by hand. It may have been serviced wrong. You may also have a clutch problem but it is obvious that you have a Maxprop problem.

[fstbttms]

Originally Posted by UFO

May 2021 - About 200 Hours of use ago

Well, the simplest initial fix attempt would likely be to lube the prop again. It's a 15 minute job underwater.

https://youtu.be/EiGowIK-GGI

[UFO]

Originally Posted by fstbttms

Well, the simplest initial fix attempt would likely be to lube the prop again. It's a 15 minute job underwater.

https://youtu.be/EiGowIK-GGI

Yeah - I might leave that one for you to come over and do - Currently in a Major Salt Water Crocodile area, so diving on the props is not high on my list of things to do - Once we move to a safer place I'll get on to it.

[chasfgr]

I've had a Brunton Autoprop, similar to the Maxprop but self-pitching.
If I ever had a problem, in the 33 years of use it was of the cone-clutch in the gearbox slipping - betokened by ample reverse drive but anaemic forward drive.
The Autoprop is totally self lubricating, the only problem was barnacle build-up, if the boat was left for long in estuarine waters.

[Jim Cate]

I've had a Brunton Autoprop, similar to the Maxprop but self-pitching.

Exactly how are these rather different props similar? To me they are radically different...

Jim