After finally being able to remove my prop shaft on my Hunter 54. I noticed that my Federal Flex Coupling was pretty much shot. In fact when it was assembled I noticed the shaft seemed to be bent. I have yet to test the shaft with a dial indicator so I do not know if it was bent or if the coupling was causing it. Online I found a new Federal Flex coupling to replace my existing unit. But I also found the PYI R&D flex coupling that looks interesting as possible replacement. In My Opinion, Federal Coupling Pros. 1) It looks like a tried and true method of allowing the shaft to flex a little. In My Opinion, Federal Coupling Cons. 1) More expensive than a new Algonquin coupler with a PYI flex coupler. 2) My old one was made of Iron, rust city, the center section was about 20% gone. 3) Who ever installed it used iron bolts which became one with the coupler (yuk!) 4) The design could lead to a misalignment after many years. In My Opinion, PYI Coupling Pros. 1) Cost is more reasonable 2) I think it has a better design in case you hit something. 3) I think it will be in-spec longer than the federal unit given the same age and wear. In My Opinion, PYI Coupling Cons. I can't see any, does anyone else have input on this issue!
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PYI
I just installed the PYI on my Passage 42. I had previously had one on my H34. You will find the coupler to be of the highest quality. It is cast or cut so that it mimics the flange to flange joint exactly. On the 42 the prop shaft flange has a shoulder that fits inside the transmission flange to keep the shaft centered on the transmission. The PYI coupler has the inset on the prop shaft side to accomodate the shaft flange, and has the shoulder on the transmission side to fit the transmission. It come with all eight stainless steel bolts with Nylock nuts. I shopped around and found the best price by far to be on the Boat US web store. It was about 60% of the catalog price.
I just installed the PYI on my Passage 42. I had previously had one on my H34. You will find the coupler to be of the highest quality. It is cast or cut so that it mimics the flange to flange joint exactly. On the 42 the prop shaft flange has a shoulder that fits inside the transmission flange to keep the shaft centered on the transmission. The PYI coupler has the inset on the prop shaft side to accomodate the shaft flange, and has the shoulder on the transmission side to fit the transmission. It come with all eight stainless steel bolts with Nylock nuts. I shopped around and found the best price by far to be on the Boat US web store. It was about 60% of the catalog price.
One Year With PYI RandD Coupling
We've been using the RandD coupling for a year now and it reduced vibration significantly. However, I have not shortened my shaft yet - wanted to make sure it worked okay first. Possible con: If the prop hits something hard the coupling will fail - as it's designed to do to protect the transmission and drive trane. Unfortunately, if the shaft is shortened there will be limited alternatives to limp back to a port. Since the original iron couplings are still there if one had a spacer (in my case, 1.25 ins long to make up for the RandD) it could be inserted and one could keep going and order a new coupling in the mean time. What are your thoughts about grounding? Should one have a grounding strap across the RandD coupling so the zincs protect the engine? My engine is freshwater cooled so the only contact with salt is via the heat exchanger. I just have a piece of copper wire joining the two sides of the coupling until I get a good answer.
We've been using the RandD coupling for a year now and it reduced vibration significantly. However, I have not shortened my shaft yet - wanted to make sure it worked okay first. Possible con: If the prop hits something hard the coupling will fail - as it's designed to do to protect the transmission and drive trane. Unfortunately, if the shaft is shortened there will be limited alternatives to limp back to a port. Since the original iron couplings are still there if one had a spacer (in my case, 1.25 ins long to make up for the RandD) it could be inserted and one could keep going and order a new coupling in the mean time. What are your thoughts about grounding? Should one have a grounding strap across the RandD coupling so the zincs protect the engine? My engine is freshwater cooled so the only contact with salt is via the heat exchanger. I just have a piece of copper wire joining the two sides of the coupling until I get a good answer.
Hey, John..
If I remember correctly you have a Legend 35.5 or 37.7. They had fresh water cooled Yanmars. The heat exchanger is insulated from the rest of the engine via gaskets. Hence the reason they do not need zincs. Don't know if this answers your question completely. Pat
If I remember correctly you have a Legend 35.5 or 37.7. They had fresh water cooled Yanmars. The heat exchanger is insulated from the rest of the engine via gaskets. Hence the reason they do not need zincs. Don't know if this answers your question completely. Pat
Rich, PYI Model Number
Rich, could you provide the part number of the PYI product you used on your P42 ? Was the installation straight forward ? Thanks.
Rich, could you provide the part number of the PYI product you used on your P42 ? Was the installation straight forward ? Thanks.
Victor, I don't know the part number....
but the shaft is 1 1/4 inches and the outside of my shaft log was 2 7/16 inches. I ordered the model that was 1 1/4 for the shaft and 2 1/2 for the log. It went right on. The easiest access (THATS A MISNOMER) on the P42 is to take the lower battery out, tray and all. That gives access to the area. You will still be working at arms length. It took about 4 hours to get the flange off. Nothing went wrong but it is in such a horrible location. One bit of advice...tape off all the hose clamps in the area. It will reduce the number of divits that get taken out of your hands and arms. The one thing that makes the job tolerable is the fact that once you have the flange off, you can pull the prop shaft out of the boat. That lets you clean up the end of the shaft and make it possible to get the flange back on during assembly without a fight. One other suggestion, since the place is so difficult to get to, I went ahead and put in one of the shaft saver disks at the same time. No sense in going back into that area any more times than necessary.
but the shaft is 1 1/4 inches and the outside of my shaft log was 2 7/16 inches. I ordered the model that was 1 1/4 for the shaft and 2 1/2 for the log. It went right on. The easiest access (THATS A MISNOMER) on the P42 is to take the lower battery out, tray and all. That gives access to the area. You will still be working at arms length. It took about 4 hours to get the flange off. Nothing went wrong but it is in such a horrible location. One bit of advice...tape off all the hose clamps in the area. It will reduce the number of divits that get taken out of your hands and arms. The one thing that makes the job tolerable is the fact that once you have the flange off, you can pull the prop shaft out of the boat. That lets you clean up the end of the shaft and make it possible to get the flange back on during assembly without a fight. One other suggestion, since the place is so difficult to get to, I went ahead and put in one of the shaft saver disks at the same time. No sense in going back into that area any more times than necessary.
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