Off season project: prop replacement

[wikakaru]

That’s a groove in the shaft log to accept a safety wire to ensure the set screws for the cutlass bearing can’t back out.

Glad it's not a problem. I've never seen it done like that before.

--Jim

[fmueller]

Hey Jim,

When we put a feathering prop on my 27 we had to grind back the rudder side opening just a little ... I posted pictures in earlier threads. I went with Featherstream because it was the only 12" feathering prop I could find. The OEM opening in your 31 looks lots bigger proportionally, but just the same: its in the feathered position at extreme rudder angles where you might (surprisingly) find there is interference. I was surprised by this on my boat. Just mentioning this even though I assume you've vetted this, but just in case. We put the feathering prop on a dummy shaft to figure this out. Partly it's that most feathering props have more "body" forward of the center of the prop blades - add the "swing" of the feathering and you find you need to pull the prop forward in the aperture to clear the rudder at all angles.

Also, after the fact, because I now have tight clearance between the deadwood of the hull and the prop body, I had to get the custom prop puller that Featherstream sells because all the usual general purpose pullers don't slip in between my prop and the deadwood.

https://www.darglow.co.uk/product/feath ... ller-fstp/

https://www.darglow.co.uk/featherstream/

Did I notice a speed difference ?? Because we really did a nice job with the bottom paint and because my rig was finally expertly tuned, when Jerezana first got back in the water with the new prop she was just faster. It was obvious. How much to attribute to the prop is hard to say. But I think you'll notice it on light days. Its not huge, maybe 3.5 knots on a light day where you'd previously been going 3.1 or 3.2 ?? But I went from a two bladed fixed, so maybe you'll get more bang for your boat dollars ...

Cheers

[Jim Walsh]

Hey Jim,

When we put a feathering prop on my 27 we had to grind back the rudder side opening just a little ... I posted pictures in earlier threads. I went with Featherstream because it was the only 12" feathering prop I could find. The OEM opening in your 31 looks lots bigger proportionally, but just the same: its in the feathered position at extreme rudder angles where you might (surprisingly) find there is interference. I was surprised by this on my boat. Just mentioning this even though I assume you've vetted this, but just in case. We put the feathering prop on a dummy shaft to figure this out. Partly it's that most feathering props have more "body" forward of the center of the prop blades - add the "swing" of the feathering and you find you need to pull the prop forward in the aperture to clear the rudder at all angles.

Also, after the fact, because I now have tight clearance between the deadwood of the hull and the prop body, I had to get the custom prop puller that Featherstream sells because all the usual general purpose pullers don't slip in between my prop and the deadwood.

https://www.darglow.co.uk/product/feath ... ller-fstp/

https://www.darglow.co.uk/featherstream/

Did I notice a speed difference ?? Because we really did a nice job with the bottom paint and because my rig was finally expertly tuned, when Jerezana first got back in the water with the new prop she was just faster. It was obvious. How much to attribute to the prop is hard to say. But I think you'll notice it on light days. Its not huge, maybe 3.5 knots on a light day where you'd previously been going 3.1 or 3.2 ?? But I went from a two bladed fixed, so maybe you'll get more bang for your boat dollars ...

Cheers

Thanks for sharing your experiences and thoughts. It looks as though I will not have any clearance issues but the proof will be when the trimmed shaft returns from the prop shop and the prop is in its final position. Fingers crossed.
I’ll be the first to admit this is a vanity project. My return on investment will be negligible but I’ll attribute any perceived increase in speed to my improved hydrodynamics……

[Jim Walsh]

This project is completed. The shaft was shortened, balanced, faced to fit flush with the coupling, and the shaft was relieved to accept the coupling set screws. The prop hub and shaft were lapped for a precise fit and the keyway broached to accept a slightly longer shaft key. The PSS shaft seal was replaced with a PSS Pro Shaft seal, the latest iteration of the product. My original was about a dozen years old. The cutlass bearing was also replaced.

[Jim Walsh]

A couple more photos..

[wikakaru]

Pretty! Shiny! You're going to love the feathering prop.

Tip: Right after you launch the boat, find a spot of flat water with no current and log your speed through the water under power at 100 RPM intervals from idle speed to wide open throttle. You can use that information as backup "knotmeter" for speed under power should instruments fail, and also later on as a benchmark for how bad your underwater fouling has become to spur you to clean the bottom and prop as necessary. Also, compare your maximum RPM at wide open throttle to the engine manufacturer's specs to help determine if the prop is pitched correctly.

Smooth sailing,

Jim

[Jim Walsh]

Good info, thanks. One of the features that sold me on this prop is how easy it is to change the pitch. All I have to do is remove one set screw and replace one pitch adjustment screw for another, reinstall the set screw and it’s done. It came with several pitch screws so it’s easy find the one which delivers the performance you desire. Can’t wait test it…..only weeks from today.

[John Stone]

Hi Jim,

In order to replace the PSS Seal on my boat last Winter I removed the shaft from the flange on the transmission myself (after some very helpful tips from this forum). It is tight getting under the cockpit but the PSS Seal replacement was pretty easy after that. Hope that your project goes well.

I was going to have my prop balanced and the shaft and flange machined but I couldn't get the prop off.
How did you get the old prop off?

Heated it with a MAPP torch. It helped that it was about 35° that morning. Three whacks with a four pound sledge against an aluminum drift, so as not to damage the prop or shaft.

Good progress for the wx your dealing with in NE. Spring will be there before you know it. Look forward to hearing about Orion's sailing performance with the max prop.

[Jim Walsh]

Hi Jim,

In order to replace the PSS Seal on my boat last Winter I removed the shaft from the flange on the transmission myself (after some very helpful tips from this forum). It is tight getting under the cockpit but the PSS Seal replacement was pretty easy after that. Hope that your project goes well.

I was going to have my prop balanced and the shaft and flange machined but I couldn't get the prop off.
How did you get the old prop off?

Heated it with a MAPP torch. It helped that it was about 35° that morning. Three whacks with a four pound sledge against an aluminum drift, so as not to damage the prop or shaft.

Good progress for the wx your dealing with in NE. Spring will be there before you know it. Look forward to hearing about Orion's sailing performance with the max prop.

Hoping to see an increase of a fraction of a knot….if I’m lucky. This is a vanity project but I knew that going in. All the little things do add up though. If my average days run increases I’ll have to credit the feathering prop since my sails are the same and the bottom still gets sanded every year before antifouling application in the spring.

[Jim Walsh]

Just a short update. Tested the new prop ten days ago. Amazing in forward and reverse but I was only able to attain 2,500RPM at wide open throttle. It’s easy to change the pitch as you simply remove one set screw, remove one pitch adjustment screw and swap it for the pitch adjustment screw of your choice, then replace the set screw….done. It could easily be accomplished in the water but it’s way too cold up here so I had a “lunchtime” short haul and did it then. Just tried it out today and the performance in forward and reverse is still great and I can now hit 2,750 at wide open throttle, which is much closer to the engine manufacturers specs.
As stated previously I know it’s a vanity project but the performance under power has certainly increased and I’ll get to see what difference the feathering prop makes under sail in a few days.

[wikakaru]

It's nice that it is so easy to re-pitch that prop. Prop pitch affects so much, from the obvious benefit of speed under power to much less obvious things like avoiding transom moustache and avoiding long-term engine or transmission damage.

I know I said it before, but you're going to love the feathering feature while sailing.

This prop isn't vanity, it's optimizing performance under both power and sail. It's not like you are gilding the faucets or anything...Now that would be vanity.

Smooth sailing,

Jim

[Steve Laume]

In this case I believe it is vanity.

Orion, is probably the most tricked out CD-31 in existence. Jim is now having a hard time thinking of any improvement he could possibly make to his boat. If anyone has any ideas, it would be good to submit them well before the winter layup so he can order parts.

I can see where those mushroom type, through hull fittings are definitely costing some hundredths of a knot. It might be time to change them out for some flush models. I know there are other people in our marina who would agree with me, that this is indeed a necessary and will be noticeably effective.

Seriously, that is a mighty slick looking prop. It's like you aren't going to be towing a bucket in front of your rudder.

Nice job.

[John Stone]

Nah. Not vanity. A commitment to helping a boat perform to her maximum sailing capabilities. Very cool. Max props are nice. It's what I would have if I had an aperture and could not use the folding prob I have on the FR. And yeah, all four of my through hulls are flush mounted. I suspect yours will be too one day. LOL.

[Tom Keevil]

When we bought Rover 20 years ago, it was our first boat with an engine. We had it in the boatyard, where we were living on it, replacing the engine mounts, cutless bearing and prop. We read up on removing props, and learned that we should put a prop puller on it, and if necessary heat it and hit it with a hammer. We borrowed a puller, but it wouldn’t budge, so we went at it with Jean’s hair dryer and a ball peen hammer. The boat next to us was a grizzled old commercial tuna fisherman, who came over to watch. He shook his head in disbelief, walked away and returned with a huge propane torch and a sledge hammer, and popped it right off. It was very educational.