Prop Shaft Rebuild CD 36

[Skylark]

I'm starting as new thread on this topic because I have searched without finding answers. I need specific information and photos of the CD 36 prop shaft log. I believe the broker who sold me this boat hacked the installation of the Cutlass bearing. Now after about 200 hours of motoring on the ICW I'm looking at my options.

1. Skylark's Cutlass is contained in a bronze fitting that is bolted to the exterior of the hull. I believe this is original.
2. The shaft packing is attached to the bronze fitting with a rubber tube.
3. Hose clamps secure the hose to the packing housing. The hose is in need of replacement.
4. No hose clamps are visible holding the hose to the exterior bronze fitting. It looks like epoxy was used.
5. The prop shaft is in need of replacement. It shows significant wear at the packing.
6. I am interested in a Max Prop 15" diameter set for a 14" pitch underway. Does the existing aperture require modification?

Please post all responses on this thread (no private messages)

Thanks

[Steve Laume]

4. No hose clamps are visible holding the hose to the exterior bronze fitting. It looks like epoxy was used.

Visible is the key word here. There are definitely hose clamps buried under that mess. You will need to chop it away and cut the band clamps to get the hose off. It is also great fun getting new ones back on.

When I pulled the shaft on Raven there was some wear at the packing as well. I took the shaft to a reputable prop shop and they didn't think it was a major issue, They recommended I alter the length of the hose to change the wear location and keep running the original bronze shaft. This not only saves the cost of a new shaft but also the cost and trouble of machining the transmission flange.

since you have everything apart and are going to have to realign the engine, this would also be a good time to consider replacing your engine mounts. 30 year old rubber just doesn't do the job like a nice fresh set of mounts do.

One things always leads to another, Steve.

[Skylark]

Thanks Steve, It sure looks like I would be digging into the fiberglass deadwood and still looking for those clamps.

A not to scale drawing.

IMG_1829.JPG (2 MiB) Viewed 1734 times

[Skylark]

And, here's a good picture from outside.

[Steve Laume]

Raven has exactly the same set up. Your drawing it close. The stuffing box hose does have hose clamps on the stuffing box side. On the end that is buried in the mismash, you are probably going to find band clamps, which are put on with a crimping tool. You also drew two bolts with nuts, holding in the shaft log. On Raven there is a bolt on the top with the grounding wire but the bottom fastener was just a large screw. I had to chop away a bunch of the mess to cut off the band clamps and then recreated it all with epoxy and filler once I had the new hose in place. I had the engine out at the time but it was still not an easy job, Steve.

[Skylark]

Oh my! So, Cape Dory had no intension of building boats that could be maintained. That hose is 30 years old.

So, the upper screw is a machine screw and, and lower is a lag. I suspected that. Glassed into place with the hose attached? Geez, and I have to basically cut it out to replace the hose.

Well, at least I have a better understanding of what it will take. I'm afraid I will have to put this off till next year and I don't trust that hose.

I've also been talking to Spartan Marine. I was hopping they would have some drawings. They don't and they also say the bronze casting for the cutlass is not one of theirs. Any idea where this may have come from?

[John Stevenson]

We did this project 2 years ago. It involved removing the shaft log with the rear half of the hose still attached. This meant removing enough material around the shaft log (perhaps 1/16") to allow for the greater OD of the hose to be pulled back through the opening. In preparation for reattaching the shaft log, the yard mechanic used West system epoxy and plenty of mold release to pre-fabricate the mounting position. We do not have pictures of the procedure but can report it worked very well. There was no need to re-align the shaft.

As it turned out, the hardest part of the procedure was to remove the forward hose clamp (cut it with a Dremul carbide bit) and the visable part of the hose.

[Skylark]

I can see why CD went out of business. They say that some were made with the hose permanently clamped to bronze fitting and was not meant to be serviced / replaced. This is not the only problem area I've found on this boat.

I will most likely replace the bronze fitting with a fiberglass shaft log. A longer tube would allow me to clamp the stuffing box hose inside the boat. However, there is very little space to work with. My CD 36 does not have the 404A flex coupling noted in the owner's manual. That coupling takes up an additional 1" and I could barely repack the stuffing box last fall.

[David van den Burgh]

In the FWIW department, our CD36, hull #7, has a bronze shaft log that the stuffing box threads onto. There's no hose at all in our arrangement. Not sure why the differences between the CDs, especially when it would appear that they started out doing it right. Sorry I don't have a picture.

Good luck!

[Skylark]

Thanks for the info everyone.
I think it would be great to start adding linked pages at http://www.capedory.org/specs/cd36.htm to make this type of information more accessible.
Or perhaps adding a wiki for this site so members could provide updates...

David,
I thought about that solution. Spartan sells something like that as a rudder port. However, I image this results in a short life for the packing due to vibration. This could be reason it was changed. It is unfortunate how limited the space is.

Myles

[David van den Burgh]

David,
I thought about that solution. Spartan sells something like that as a rudder port. However, I image this results in a short life for the packing due to vibration. This could be reason it was changed. It is unfortunate how limited the space is.

Myles

Myles,

I'm not so sure about that. I've not noticed any unusual wear on the stuffing due to the setup. It seems to be a very reliable arrangement.

David

[John Ring]

[quote="Skylark"... However, there is very little space to work with. My CD 36 does not have the 404A flex coupling noted in the owner's manual. That coupling takes up an additional 1" and I could barely repack the stuffing box last fall.[/quote]



Yep, mighty tight back there with the 404A Drive Saver flex coupling in the mix. I don't know what diesels were available in the early 1980s, but the Perkins 4.108 is just too big physically to be in that space. That Drive Saver gotta come out to make the stuffing box serviceable on Tiara (1985 CD36).

John

[Dave and Kathy]

We're restoring Grayce Avery, our 1984 CD28. We too had a stuffing box hose with the aft end buried in the mish-mash, like many others. After looking things over from outside the boat, it looked to me like there was filler beneath the upper half of the external stern tube flange. I removed the large screw below the prop shaft and the bolt above it. I then broke away the filler beneath the flange on the half above the prop shaft. Starting above the shaft opening (shaft was removed before I started), I used narrow wedges driven in simultaneously from port and starboard. Working carefully, it became apparent that the stern tube flange was moving aft. Once in a while, I'd stop to 'wiggle' it around by hand and then go back to the wedges. Eventually the stern tube fitting came out aft and left the hose and the banding inside. With the stern tube separated from it, it was then easy to go back inside the engine bay and extract the hose/band. No damage to the hull and it took about 20-30 minutes to complete. After evaluating options going forward, I am eliminating the problem by having Port Townsend Foundry, here in Washington, make a bronze duplicate of the original stern tube fitting that will penetrate 2" farther forward so I can always get to the aft hose clamps. I just talked to them this morning and plan to pick up the finished part, with cutlass bearing installed, the Monday after Christmas. (Thank you Santa!) I'll try to post a picture and let the membership know how it works out.

[Skylark]

"It became apparent that the stern tube flange was moving aft."

Sounds like there is hope. Plan to start this task in the fall. Having a new shaft log cast is probably a good option. In that case I would extent the tube and have the inside end machined and threaded to accept a packing nut. From an earlier post is seems that some of the early CD36's were setup this way. I've also found a flex coupling that appears to be more effective and takes up slightly less space. The brand name is Bullflex sold by Fetus.

[Skylark]

Found some new information.