Max prop and shaft brake?

[mlydon]

I have a velvet drive, so can’t lock the shaft with reverse. I just picked up a max prop - I’ve seen discussions where folks argue that getting a feathering prop eliminates the need for a brake, and others stating that feathering props won’t feather without a brake. PYI says it will feather....

As I am also planning on changing out the stuffing box for a dripless, now’s the time if I do need one. I’d hate to do all that work, splash the boat next spring, and still have it spinning all season.

What’s your experience?

TIA,
Matt

[TheOffice]

I shift into reverse for a few seconds to be sure the max prop feathers.

[mlydon]

Engine running? With the velvet drive, shifting does nothing if it’s not....

Matt

[Mediator]

Once I've turned off the engine, I also shift into reverse to feather my Max prop (with my ZF 15 gearbox). Otherwise it'll spin all day long.

[evm1024]

I have a velvet drive and maxprop. I've not put a shaft brake on the prop shaft but was thinking along the lines of putting a zinc on the shaft inside the boat, drilling a hole in the zinc and inserting a shear pin in the zinc and then an arm goes over the shear pin and prevents the shaft from turning.

With the arm in place the shaft does not rotate and should I space it and forget to take the arm off the shear pin would break when placed in gear.

Of course it may not be required...

Just a thought.

[HankOnthewater]

Switch engine off when gearbox is in gear, going forwards. The prop will then feather.
On my boat, after that, when the engine is not running, does not matter if I put the gearbox in reverse, neutral or leave it in forward gear, as the prop is feathered and shaft won't turn. However normally I put it in neutral 5-10 seconds (depending on the speed I am doing under sail, after I switch the engine off, so when I start the engine next time I won't be caught with the engine in gear.

Just a note, if the shaft is not spinning when under sail could mean 2 things: prop is feathered or shaft is locked by gearbox.

[stormalong]

Don't shift into reverse to with the engine running. That prevents it from feathering. Read your manual. That is the method to use if you have a shaft generator.

All you have to do to make it feather is to stop the shaft from turning momentarily - after the transmission was in forward last time it was engaged. If your transmission cannot stop the shaft from turning with the engine off you probably need a shaft brake. The good news is that you only need to use the shaft brake for a moment so a good habit would be to use it and release it a moment later so you won't forget it is set and engage the transmission.

[bradandnatalie]

I have just recently swapped out my worn Maxi Props for fixed. The manual states to turn the engine off whilst in forward gear to allow the blades to feather. Then put the gear into reverse. If your gear box shouldn't be in gear whilst you're underway (that is you should be on neutral) then you're going to have a problem. If the shaft is allowed to spin it can rotate in the boss and knock the blades into an open or semi open position. You will need to stop your shaft shaft from rotating. If you can install a shaft brake so much the better but allowing your shaft to rotate may well negate the advantageous of having feathering props. Good luck.

[jamhass]

A friend with that setup tells me he really wishes he had a shaft lock for exactly the reasons stated, and says that if you have a convenient opportunity to install one, go for it, as it adds a lot of convenience if nothing else.

[4palmer]

I have a 4 blade. The only negatives of the max prop and other folding props is the requirement to replace zinc on the cap every 6 months as well as lube. There are very few divers that can do that.

[macman4190]

I shut down engine in gear. Prop feathers quickly, then I put transmission in neutral. Shaft doesn’t spin after blades are feathered. Not even after several days of sailing.

[svspirited]

With a max prop you kill the engine while it is still in forward gear, that will feather the prop and you then put the transmission into neutral. You will not have to lock it with a brake or shift into reverse. This is how PYI recommends getting them to feather properly and once feathered the shaft should not spin.

[Mediator]

From the PYI FAQs page:

"The best way to feather the propeller is:

Power at 2 to 3 knots in forward.
Kill the engine while still engaged in forward.

If your propeller has been greased properly it will feather in a fraction of a second as soon as you stop the shaft from freewheeling. DO NOT kill the engine while in reverse. In this case the blades will be held in the reverse position by the flow of the water and cannot feather. Modern transmissions are either mechanical or hydraulic. With a mechanical transmission, the best way to stop the shaft freewheeling is to engage the transmission in reverse (WARNING: engage the reverse only after the engine has stopped completely). With a hydraulic transmission you must shut off the engine while still engaged in forward. The remaining hydraulic pressure will in effect stop the shaft for a few moments, enough for the Max-Prop to feather."

https://www.pyiinc.com/max-prop.html#faq

[tml]

We had a 3 blade max prop on a velvet drive for 20 years. Never needed any sort of shaft brake. stop the engine with the transmission in forward. You will hear the shaft spin and then stop.Best if speed was 5kts or better when the engine was killed.
Tom

[fstbttms]

Originally Posted by 4palmer

I have a 4 blade. The only negatives of the max prop and other folding props is the requirement to replace zinc on the cap every 6 months as well as lube. There are very few divers that can do that.

1.- Max Prop is not a folding prop

2.- There is no requirement to replace the anode or lubricate the prop every six months

3.- Even if there was, both anode replacement and lubrication are exceedingly easy and if your diver is incapable, find a new diver